Eagle Bluff
Alternative Energy for the Future
Design report
Project Number
May 04-10
Client
Eagle Bluff Environmental Learning Center
Joe Deden, Executive Director
1991 Brightsdale Road
Route 2 Box 156A
Lanesboro, MN 55949
Faculty Advisors
Dr. James McCalley
Dr. Mani Venkata
Dr.Delly Oliveira
Team Members
Abdul Kader Abou Ardate
Darko Brokovic
Daniel M. Disenhouse
Lucas J Kirkpatrick
REPORT DISCLAIMER NOTICE
DISCLAIMER: This document was developed as a part of the requirements of an electrical and computer
engineering course at Iowa State University, Ames, Iowa. This document does not constitute a professional
engineering design or a professional land surveying document. Although the information is intended to be
accurate, the associated students, faculty, and Iowa State University make no claims, promises, or
guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of this
document shall ensure that any such use does not violate any laws with regard to professional licensing and
certification requirements. This use includes any work resulting from this student-prepared document that
is required to be under the responsible charge of a licensed engineer or surveyor. This document is
copyrighted by the students who produced this document and the associated faculty advisors. No part may
be reproduced without the written permission of the senior design course coordinator.
May 5, 2004
Table of Contents
List of Figures and Charts ...................................................................................... LOF-1
List of Tables ............................................................................................................ LOT-1
List of Symbols ......................................................................................................... LOS-1
List of Definitions ..................................................................................................... LOD-1
Introductory Materials ..................................................................................................... 1
Executive Summary ...................................................................................................... 1
Recommendation ........................................................................................................ 2
Acknowledgment ........................................................................................................... 3
Problem Statement........................................................................................................ 4
General Problem Statement ............................................................................................ 4
General Solution Approach............................................................................................. 4
Operating Environment ............................................................................................... 4
Intended Users ............................................................................................................... 4
Intended Uses ................................................................................................................ 5
Assumptions................................................................................................................... 5
Limitations ..................................................................................................................... 5
Expected End Product and Other Deliverables ......................................................... 6
Approach and Design ....................................................................................................... 7
A.
Design Objectives .................................................................................................. 7
B.
Functional requirements ...................................................................................... 7
LOF-1
C.
Resultant Design Constraints............................................................................... 7
WIND .......................................................................................................................... 8
Biothermal................................................................................................................. 13
Solar .......................................................................................................................... 15
Fuel Cells .................................................................................................................. 20
Hydro ........................................................................................................................ 22
Microturbine ............................................................................................................. 24
Load Management .................................................................................................... 27
E. Recommended Design Approach .......................................................................... 34
F. Detailed Design ....................................................................................................... 35
Current System.......................................................................................................... 35
Technical Specifications of the Proposed Design ..................................................... 38
Final Plan .................................................................................................................. 43
Recommendation ...................................................................................................... 48
Resource and Schedules ................................................................................................. 49
Resource Requirements .............................................................................................. 49
Schedules...................................................................................................................... 53
Closure Material ............................................................................................................. 55
Project Evaluation ...................................................................................................... 55
Recommendations for Additional Work................................................................... 55
Lessons Learned .......................................................................................................... 55
Risk and Risk Management ....................................................................................... 55
TOC-2
Project Team Information ......................................................................................... 56
Closing Summary ........................................................................................................ 58
References .................................................................................................................... 59
Appendix A – Wind Data ............................................................................................. 1
Appendix B – Load Data .............................................................................................. 1
Appendix C – Hydro Data ............................................................................................ 1
TOC-3
List of Figures and Charts
Figure 1: An Example of Energy Supplied by Multiple Sources ...................................... 6
Figure 2: Wind capture ....................................................................................................... 9
Figure 3: Betz Limit .......................................................................................................... 10
Figure 4: BioMax generator .............................................................................................. 14
Figure 5: Typical solar roof design ................................................................................... 16
Figure 6: Components of the solar electric system. .......................................................... 17
Figure 7: Solar Application ............................................................................................... 19
Figure 8: Fuel Cell ............................................................................................................ 20
Figure 9: A single fuel cell membrane electrode ............................................................. 21
Figure 10: Typical Hydro Design ..................................................................................... 23
Figure 11: Water Fall of a Hydro Plant ............................................................................ 23
Figure 12: Flow system for a microturbine....................................................................... 26
Figure 13: Microturbine system ........................................................................................ 27
Figure 14: Geothermal Pumps .......................................................................................... 31
Figure 15: Installed Cost ................................................................................................... 33
Figure 16: One-line diagram of the current system .......................................................... 36
Figure 17: One-line diagram of biothermal unit and the inter-tie ..................................... 45
Figure 18: One-line diagram of wind turbine unit and the inter-tie .................................. 45
Figure 19: One-line diagram of final plan ........................................................................ 46
Figure 20: Shifted wind curves for 2001 wind profile ...................................................... 47
Figure 21: Yearly power output of the wind turbines with shifted wind profile for 2001 47
Figure 22: Chart of Original Effort ................................................................................... 51
LOF-1
Figure 23: Chart of Updated Effort ................................................................................... 51
Figure 24: Actual Time Spent ........................................................................................... 52
Figure 25: Gant Chart of Projects and Deliverables ......................................................... 54
LOF-2
List of Tables
Table 1: Wind Bins Sample ................................................................................................ 9
Table 2: Average Electric kWh/year................................................................................. 11
Table 3: Economic Analysis ............................................................................................. 12
Table 4: Biothermal costs and generation ......................................................................... 15
Table 5: Hydro facts.......................................................................................................... 24
Table 6: Microturbine facts ............................................................................................... 26
Table 7: Single Lamp Relamp .......................................................................................... 29
Table 8: 4 vs. 3-Lamp ....................................................................................................... 30
Table 9: Efficiency of different approaches...................................................................... 32
Table 10: Fuel Costs ......................................................................................................... 33
Table 11: Campus electrical energy facts ......................................................................... 37
Table 12: House electrical energy facts ............................................................................ 37
Table 13: Shiitake electrical energy facts ......................................................................... 37
Table 14: Schroeder electrical energy facts ...................................................................... 38
Table 15: Entire Facility electrical energy facts ............................................................... 38
Table 16: Wind generation costs....................................................................................... 38
Table 17: Biothermal generation costs ............................................................................. 39
Table 18: Insurance compared to other states ................................................................... 40
Table 19: Generation Interconnection summary............................................................... 41
Table 20: Combined generation costs ............................................................................... 46
Table 21: Personnel Effort Requirements ......................................................................... 49
Table 22: Revised Personnel Effort Requirements ........................................................... 50
LOT-1
Table 23: Final Individual Effort Requirements ............................................................... 50
Table 24: Estimated Financial Cost .................................................................................. 52
Table 25: Revised Financial Cost ..................................................................................... 53
Table 26: Actual Estimated Project Cost .......................................................................... 53
LOT-2
List of Symbols
KW:
KV:
MV:
MW:
kg:
Kilo (103) Watts
Kilo (103) Volts
Mega (106) Volts
Mega (106) Watts
Kilo (103) Grams
LOS-1
List of Definitions
Biothermal – The use of biodegradable products such as wood and corn stalks to create
electrical energy.
Grid – The transmission network that connects all power lines and nodes
Interconnection – The point of connection between a power source and the utilities
distribution or transmission system.
IPP – Independent Power Producer
NEC – National Electric Code
NESC – National Electric Safety Code
LOD-1
Introductory Materials
Executive Summary
Eagle Bluff Environmental Learning Center requested that a study be performed to
evaluate possible renewable energy resources. The following describes the project’s
needs, activities, final result and the project’s recommendation.
Project Need
Eagle Bluff’s goal is to fulfill their energy needs using cost effective renewable
resources. In-order to determine the available energy resources and the feasibility of the
project, a study was required. The study needed to examine the available technologies,
technical requirements as well as economic feasibility.
Activities
There were number of activities involved in performing the study. These activities
included research and investigation of the following technologies:
 Wind
 Biothermal
 Solar
 Fuel Cells
 Hydro
 Microturbines
 Load Management
After these technologies were researched, Eagle Bluff was presented with the economics
of each resource. Eagle Bluff then requested that an in-depth plan combining wind and
biothermal technologies be developed. This plan was developed by studying several wind
turbines and biothermal units. A variety of wind turbines with different characteristics
were discovered. However, there were few biothermal units that fit Eagle Bluff’s energy
requirements.
Final Result
The final result was a plan which connected two wind turbines and a biothermal unit to
the utility’s distribution system. The power produced would be delivered to Eagle Bluff
over Tri-County Electric’s distribution lines. The final plan detailed the major
components of the interconnection and presented an economic analysis. The figure below
shows a one-line diagram of the final plan.
1
Wind
Turbine
Inter-tie
Peterson Circuit 4
5250 kVa
Transformer
Inter-tie
3 miles of Overhead 1/0 ACSR
Bio
Thermal
1 mile of
Underground 1/0
Aluminum
Eagle Bluff Facilites
The facilites have 4 transfomers
Overhead 1/0 ACSR
1-300kVA
1-15kVA
Underground 1/0 Aluminum
1-150kVA
1-25kVA
Transfomer
The economic analysis showed that 2 turbines would be the cheapest with a project
present worth cost of $634,566 for a 25 year span. With the addition of a back-up thermal
unit, the cost rises to $883,458. These costs where compared with the present worth of
Eagle Bluff’s usage for the next 25 years. This resulting cost known as the break-even
project cost is $403,136.
Recommendation
The research and consultations with Eagle Bluff concluded that a wind turbine and a
biothermal resource was the best approach. However, an economic analysis showed that
the developed plan would be more than the break-even cost. As a result, this study
concluded that alternative energy would only be an economically viable solution if
government grants and outside donations were received.
2
Acknowledgment
Eagle Bluff has been very helpful in the initial consultations. They were able to identify
their specific zone of interest and were more then willing to supply the necessary
information for demand calculations. They provided the team with monthly electric bills
and blueprints. The clients were also very cooperative and took the team on a tour
through the buildings showing their main load demands. Also, Eagle Bluff initiated the
collection of local wind measurements and briefed the team on the facility’s bio-energy
resources.
Bob Spartz of Tri-County Electric gave access to detailed information that was received
from Tom Nigon of PowerPlus Engineering. Tom provided our team with a transmission
layout, as well as the services that Eagle Bluff receives.
Jerod Smeenk from Iowa State University Department of Mechanical Engineering
provided the team with cost estimates and information regarding renewable resources.
Dr. James McCalley, Dr. Mani Venkata, and Dr.Delly Oliveira have provided many
suggestions and expertise in guiding the team through the project. They have spent
numerous extra hours in developing the project.
3
Problem Statement
General Problem Statement
Eagle Bluff is a residential environmental learning center located in southeast Minnesota.
Its maximum energy consumption is 300 KW. The center would like to become energy
self-sufficient and remove itself from the electrical grid, except for backup purposes. The
center is looking for a solution that is environmentally friendly, reliable, economically
feasible and cost effective. A plan that meets these criteria should provide a number of
energy sources, necessary electric designs, economic analysis, and a cost analysis.
General Solution Approach
In order to provide Eagle Bluff with the required plan, a variety of energy sources and
storage devices were investigated. These sources included wind generation, hydrogen
production, solar cells, fuel cells, and biothermal. The electric layout needs were
investigated and a proper system was designed. All governmental and industrial
regulations that apply to Eagle Bluffs situation were investigated and the results were
reflected in any design. At the end of the research, recommendations were given to Eagle
Bluff on what systems they should implement according to their finances, location and
the available resources. The expected end product is a report that includes: (1) system
requirements and environment, (2) options considered and descriptions, (3) prioritized
options and reasons for prioritization, (4) a detailed system design and (5) economic
analysis of investment cost and future operating cost.
Operating Environment
Minnesota weather is known to range from hot to cold. Any system designed for Eagle
Bluff will need to withstand wind, snow, ice, and low and high temperatures. Because of
the latitude, summer daylight hours are long while winter daylight hours are short. These
factors were considered when deciding on particular types of equipment for power
generation. In the case of solar, wind or fuel cells, they need to be placed in particular
location to best optimize the sun, wind, and temperature. Using Minnesota wind
demographics as well as average solar exposures for the area needs were taken into
account when performing energy calculations.
Intended Users
The plans created by the design team are intended to be used by Eagle Bluff in selecting
new energy sources. The plans will allow Eagle Bluff to determine what forms and
amounts of energy sources they would like to install. Also the plans will allow money to
be raised to install the new generation and electrical systems. The plans will be used by
potential sponsors in determining if Eagle Bluff meets the donation requirements.
Visitors to the center will benefit from the implementation of the design. They will be
able to view renewable resources and see energy production as it happens.
4
Intended Uses
Expected uses are separated into two categories:
1. The project will be used to give Eagle Bluff and understanding of the possible
energy solutions. Also the project will be used to determine the best plans for
producing electric energy in the most economical and environmentally
friendly way. The ultimate goal of having some form of the plans
implemented.
2. This project should increase education opportunities in the Eagle Bluff
learning community and open awareness of energy conservation and clean
energy production.
Assumptions
There are seven assumptions listed for this project:
1. The total power needed will not exceed 1 MW.
2. The protective system used will be accepted by the local utility.
3. Project provides reliability of the system and its actual dependency on the
electrical grid.
4. The wind shear factor equals 0.2; a value of 0.1 for roughness length was
estimated.
5. The utility’s avoided cost is $0.022/kW
6. Tax breaks and government grants are not included in the current cost
analysis.
7. The monthly billing from Tri-County will be the net difference of power
produced and power used plus all standard connection fees.
Limitations
There are six limitations listed for this project:
1. Alternative energy resources must be environmentally friendly.
2. The project must include a protective system, that consists of a proven
technology and applicable for Eagle Bluff.
3. The project results are to be understandable by persons not familiar with
energy production and distribution. It needs to be understandable so it can
be used as an educational material for students visiting the Eagle Bluff
learning center.
4. Limited access to wind and sunlight due to geographical location and
unpredictable weather.
5. Generation size must satisfy local utilities’ interconnection requirements.
6. Wind speed data must be economically viable for wind turbines
5
Expected End Product and Other Deliverables
The expected end product is an in-depth plan which uses a combination of wind and
biothermal. All considered resources will be discussed with reasons provided for the
chosen solution. A solar unit will also be considered for educational purposes. Eagle
Bluff should be able to use the plans to raise money and support for the goal of becoming
energy self-sufficient. The goal of the project does not include delivering any hardware or
software product to Eagle Bluff.
Wind
Generator
Bio-Thermal
Unit
Legend
Electrical Lines
Energy Sources
Facilities
Utility Connection, Transformers
and Protection Equipment
Figure 1: An Example of Energy Supplied by Multiple Sources
6
Approach and Design
A. Design Objectives
The following is a list of the design objectives:
1. Minimum size of 300kW – This is Eagle Bluff’s maximum demand.
2. Renewable energy sources – This falls under the environmental friendly
purposes of Eagle Bluff.
3. Final detailed plan using wind and biothermal – They fall into the guidelines
of being cost affective and environmentally friendly.
4. Other options considered – A discussion on why some of the other options
considered and reasons will be given for not further developing them.
B. Functional requirements
The following is a list of the functional requirements:
1. Meeting the demand power consumption of Eagle Bluff – The combination of
power resources that Eagle Bluff can use must meet the demand needed to
fully maintain their facility.
2. Minimum impact on the environment – Being an environmental friendly place
with the least amount of impact on the environment.
3. Upgradeable system design – The design would allow the facility to upgrade
the system to generate more power in regard to their needs and expansions.
4. Staying connected to the electrical grid and selling any excess power – The
design would help to offset the costs associated with new generator as well as
helping to lower costs of daily activities.
5. Back-up generator on standby – This will help if main source becomes
unusable for a period of time
6. Educational use – To have the ability to show visiting people the alternative
methods of power production
C. Resultant Design Constraints
The following is a list of the project constraints:
1. Weather resistant – extreme temperatures; wind, rain, and snow that may limit
wind and solar power generation – Wind and solar are not constant which
would limit their use and increase the use of backup power supply.
2. Cost – Cost of implementing the plan and cost of maintenance as well as the
possible fuel supply and storage for certain types of generation should be
equal to or less than the current costs.
3. Resources – Land availability and location of generator
4. Reliability of Generation –How reliable is the source of generation
7
5. Maintenance requirements – The amount of maintenance required and the
lifespan of the generation equipment
6. Interconnection limitations – Generation should not exceed 1MW due to grid
connections requirements.
7. Minimum size of 300kW – This is Eagle Bluff’s maximum demand.
D. Technical approach considerations
There are a number of energy technologies that have been investigated as possible
solutions to Eagle Bluff’s needs:
 Wind
 Biothermal
 Solar
 Fuel Cells
 Hydro
 Microturbines
 Load Management
These technologies are discussed below.
WIND
The first step taken to study the possibility of having a wind turbine up at Eagle Bluff
was to determine the wind profile for that specific area. Wind measurements for Eagle
Bluff were available online at “Minnesota Wind Sites”. The device up at that particular
site has a sensor height at 20, 29 and 30 meters and recorded wind speed and direction
from 10/14/2000 to 8/4/2003 as ten minute averages (Samples of wind speed statistics are
provided in Appendix A). All the wind speeds were put into spreadsheets and the time of
the year each wind speed blows was calculated. Table 1 below shows the speed of the
wind and the time of the year in hours this particular speed is blowing (frequency) at 30
meters height. The total number of hours for all the wind speeds sums up to 8760 hours
which is exactly the number of hours in one full year.
After finding the wind speed measurements, the challenge was to calculate how much
electrical energy capability such a site holds. For that, many factors of wind were
introduced; roughness length, shear, Betz limit, density, elevation, height and many
others that are not directly related to the wind. To fully understand the final numbers
accompanied with these measurements, a simple yet clear explanation of some of the
factors that had a significant influence on the calculations are presented.
8
Table 1: Wind Bins Sample
Wind Shear:
The fact that wind speed decreases when moving closer to ground level
is often called wind shear; more height means faster wind. This factor
was introduced to the wind calculations because the wind measurements
available were at 30 meters height. The wind shear formula presented
below provides wind speed at any desired height
v
= vref * ln(z/z0 )/(ln(z ref /z0 )) ...(equation1)
v
= wind speed at height z above ground level.
vref
= reference speed; known wind speed at height z ref .
ln
=
the
natural
logarithm
function.
z
= height above ground level for the desired velocity, v
z0
= roughness length (explained in the next section)
z ref
= reference height; known height at the exact wind speed vref
assuming
z
= 70 meters
z ref
= 30 meters
z0
= 0.1
v/vref = ln(z/z0 )/(ln(z ref /z0 )) = ln(70/0.1 )/(ln(30 /0.1 ))
this is equal to 1.149
mph
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Hours/year
518.28
329.32
297.67
396.17
530.97
675.85
721.2
703.77
703.97
647.04
559.17
464.46
400.73
358.07
308.8
246.45
216.99
176.57
128.27
98.291
74.691
Roughness Length:
Is defined as the height above ground level where the wind speed is theoretically zero.
This factor is important because it directly related to wind speed; the more roughness of
earth surface there is, the more likely that wind will be slowed down. Since the particular
site at Eagle Bluff is an open agricultural area without fences and hedgerows and very
scattered buildings, a value of 0.1 for roughness length was estimated. This places the site
at roughness class 2 (this is only an estimated value, a more accurate roughness length
will be determined later). This value was used in equation one to determine wind speed at
any desired height.
Betz Law (limit):
Betz Law simply states that a wind turbine can only convert
59% of the wind kinetic energy of the wind into mechanical
energy. Assuming that one can capture 100% of the wind
striking the rotors of the wind turbine, the move-away air
would have a zero speed (v2=0); rotors will not rotate. On
the other hand, if we capture none of the wind (v1=0), rotors
will not turn either. However, there is a way
Figure
2:
Wind
http://www.windpower.org
9
capture
in-between the two extremes to capture the maximum
possible amount of wind energy.
Using Newton’s second law:
P = (1/2)*m*(v12- v22) = (1/2)*( *A*(v 1 + v 2 )/2)*(v12- v22)…(equation2)
P = the power extracted from the unit by the rotor
m = the mass of the air streaming through the rotor during one second
= the density of the air (1.2 Kg/m3)
A = the wind turbine blade area
v1 = wind speed in front of rotor
v2 = wind speed behind rotor
P0 = ( /2)* v 1 3 *A…(equation3)
Where P0 is power from the wind through the same area with no rotor to block the wind
Now Cp = P/ P0 = (1/2)*(1 - (v2 / v1 ) 2 ) (1 + (v2 / v1 ))…(equation4)
Plotting Cp verses v2/v1 shows that Cp reaches its maximum value of 59%when the ratio
v2/v1 is 1/3.
From here, it is obvious that the effectiveness of any
wind turbine is measured by the power coefficient Cp
which is defined as the power delivered by the rotor
divided by the power in the wind striking the area swept
by the rotor.
Figure 3: Betz Limit
Wind Turbines:
Wind turbines vary in sizes and shapes, one aspect of wind turbines that is very helpful in
determining the electrical energy output of a wind turbine is the power curve. A power
curve of a wind turbine determines how much power in Watts (W) is produced at a
certain speed (mph or m/s).
Extensive research has been done on wind turbines to describe the best turbine to meet
Eagle Bluff needs; electrical and economic wise.
The shear coefficient is estimated from equation1 to be about 0.2. This coefficient
provides a conversion between the annual generation of power at reference height to the
annual generation of power at desired height
G2 = G1*(z/z ref)^(shear coefficient) = G1*(z/z ref)^(0.2)…equation5
10
Calculations for the power output for several wind turbines are conducted provided using
the following calculated and given numbers:
a. The power curve of the wind turbine to be considered (see Appendix A)
b. The frequency of wind at Eagle Bluff (see Table 1)
The power output corresponding to each wind speed is multiplied by the hours per years
that particular speed is blowing which gives: kW*hours/year = kWh/year. This Total
generation of electric power is assumed at air density of 1.225 kg/m3.
Wind turbines considered and their outputs
Four generators have been considered and analyzed last semester. However, closer
look at the wind profile of Eagle Bluff shows that wind is between .25 and 24, with an
average of 8.22 mph for the major amount of time in the year. This gave the team an
indication that a wind turbine that can reach its rated capacity at low wind speeds would
be more efficient for the location at Eagle Bluff. The best wind turbine found by the
group is Suzlon 1 MW rated capacity. The five wind turbines considered were
1. Fuhrlander 250kW 30m rotor
2. Vestas 660kW 47m rotor
3. Micon 750kW 48m rotor
4. Mitsubishi 1000kW 56m rotor
5. Suzlon 1 MW 64m rotor
Using the power curves provided in the appendix, the annual power generation for
each wind turbine was calculated for 2001 and 2002 (calculations for 2003 were not
possible due to the lack of wind speeds after 8/5/2003). The values initial obtained were
actually at the reference height z ref = 30 meters. Using equation5 with the estimated
shear coefficient of 0.2, the desired output was calculated at the desired height z = 70
meters. The annual kWh generations for years 2001 and 2002 are presented in the table
below
Table 2: Average Electric kWh/year
2 Fuhrlander
Vestas
250kW 30m
660kW 47m
rotor (kWh)
rotor (kWh)
2001
429,040
447,923
2002
505,125
539,792
Micon
750kW 48m
rotor (kWh)
568,320
673,630
Mitsubishi
1000kW 56m
rotor (kWh)
704,144
839,001
Suzlon
1000kW 64m
rotor (kWh)
1,064,065
1,251,174
Since a 250 kW wind turbine is actually less than the average instantaneous consumption of
electricity at Eagle Bluff, two 250 kW wind turbines are considered. This step actually has a very
important reliability advantage. In case one of the turbines should stop functioning, the second
turbine would, the facility would still be getting half the initial power. This is a very important
point that Eagle Bluff personal should consider.
Costs and Economic Analysis
The prices of wind turbines have decreased by 80% in the past 20 years. And the
11
wind market of production of energy increases by 30% each year. With the new
regulations, the wind energy is growing so fast that NERC is already making changes in
the distribution of energy throughout the whole nation.
Prices of wind turbines vary in-relation to the power rating of each of them, the blades
diameter and also the tower height. But the average cost of turbines is about $2000/kW.
Adding installation costs and maintenance costs raises the price up to about $2250/kW.
Operation costs of wind turbines are very low of about $0.01/kW.
Economic analysis is conducted for a life span of 25 years, which is the expected
operational time of the wind turbines and the biothermal unit. The salvage values of all
machines are estimated at 10% of the capital cost. The net present worth (NPW) and the
internal rate of return for investments (IRR) is calculated for all the different options and
combinations of wind turbines and the biothermal unit as well as the increased cost over
the $0.06/kWh that Eagle Bluff is currently paying.
Table 3: Economic Analysis
Machine Used
Capital
Cost
NPW (6%)
IRR %
Increased Cost
$/kWh
2 Fuhrlander 250kW 30m rotor
$1,000,000
-$ 634,566
-2%
$ 0.051
Biothermal
$ 60,000
-$ 68,680
-15%
$ 0.010
Vestas 660 kW 47m rotor
$1,320,000
-$ 918,667
-3%
$ 0.069
Micon 750 kW 48m rotor
$1,500,000
-$ 1,065,550
-3%
$ 0.064
Suzlun 1 MW 64 m rotor
$2,000,000
-$ 1,429,063
-9%
$ 0.046
2 Fuhrlander 250kW 30m rotor + Biothermal
$1,060,000
-$ 883,458
-5%
$ 0.046
Vestas 660 kW 47m rotor + Biothermal
$1,380,000
-$ 1,188,915
-6%
$ 0.060
Micon 750 kW 48m rotor + Biothermal
$1,560,000
-$ 1,335,799
-6%
$ 0.058
Suzlun 1 MW 64 m rotor + Biothermal
$2,060,000
-$ 1,699,311
-5%
$ 0.045
Break- even
In Table 3 above, the present worth of each combination of machines is calculated. These
values represent the present worth of the cost for the project with a 25 year life span.
These values can be compared with the present worth of what Eagle Bluff would pay the
utility over the next 25 years given its present usage assuming a 6% return on investment.
The present worth of Eagle Bluffs bill for the next 25 years is as follows:
 Average kWh usage per year = 525,600 @ $0.06 per kWh = $31,536
 The NPW (6%) = $403,136
12
From these values, we can see that the NPW Break-even investment cost is $403,136
So, the less costly option is the 2 Fuhrlander 250kW wind turbines that have a NPW of the
cost after 25 years of $634,566.
Disadvantages of wind turbines
There are a few disadvantages accompanied with the wind turbines.
 Neighbors don’t like them because they are noisy, the blades constantly
make noise when rotating
 They take a lot of land space to install, this is a major concern especially
to farmers because they prefer to use that land space for agricultural
purposes
Biothermal
Biothermal is one of the many technologies that are being considered as an energy source
for Eagle Bluff. As with all sources of energy, there are a number of factors that must be
examined:
 Fuel source
 Types of technologies
 Power output
 Installation cost
 Operating cost
 Equivalent annual cost
Each of these factors is briefly discussed below and the biothermal technology that is
currently being considered for Eagle Bluff is presented.
Fuel Source
Biothermal energy is energy that is obtained from biodegradable products.
technology covers a wide territory and includes a number of fuels:





This
Wood
Switch grass
Rice hulls
Manure
Corn
These sources can be burned to obtain heat directly or the heat can be use to produce
electricity by using a turbine. As discussed in technologies, some devices use some of
the energy as direct heat and the rest produces electricity. This is system is used to
increase total efficiency
13
Types of Technologies
There is quite of variety of technologies that come under the heading of biothermal.
Some systems burn the fuel source directly to produce heat while others gasify the fuel
and then burn the gas to produce heat. Another method is used in the case of manure.
The methane from the manure waste is collected, cleaned and burned. In all of these
cases, the energy output is either used to directly produce heat or the heat is used to
produce electricity. Under a co-generation system, both heat and electricity are collect
and used from the output.
Power Output
Biothermal generating units vary in size from a 5kW to 20MW. The larger units tend to
be co-generation systems that act much like a typical coal plant; the burned fuel is used to
operate a steam generator. Small generation units are often used to produce heat for
room or a small building. As a result of some government sponsored studies, some
generating units that produce 10kW to 30kW are being developed. Some of these units
are gasifying fuel such as wood to produce heat. Currently there does not appear to be
many technologies that produce electricity in the 100kW to 500kW range.
Costs
There are a number of costs that must be examined when studying biothermal units. The
technologies that produce electricity have an investment cost of $2,000 per kW. The
annual operating and maintenance cost are estimated to be $.08 to $.12 per kW if fuel
costs are not included. Combining investment costs and operational cost, an estimated
equivalent annual cost of $.20 per kW is obtained. These are rough industry estimates
and subject to the technology type and tax breaks.
Figure 4: BioMax generator
14
Technology Considered for Eagle Bluff
Based on the discussed factors, the unit that is currently being examined which will help
stratify Eagle Bluff’s needs is a 30kW BioMax generator produced by Community Power
Corporation. This device is a self contained unit that gasifies wood to produce electricity.
While the unit does not meet all of Eagle Bluffs peak demand, it will supply energy for
the small buildings and a series of them can be used to produce more power. The
BioMax system power output and cost currently follow the industry trend. However, as
more units are produced these costs will come down.
Table 4: Biothermal costs and generation
Biothermal Plan(assuming no fuel cost)
Size(kW):
Lifetime (years):
Installation Cost:
Operation and Maintenance ($/kW)
Yearly kWh output
Annual Cost (6% interest)
Cost ($/kWh)
(Cost if installation not considered($/kWh)
30
30
$60,000.00
$0.085
262800
$26,696.93
$0.19
$0.085
Solar
Solar generation technology does not date way back like the other energy generation
technologies. It has been in experimenting and developing phases since 1970’s. However
it is just recently technological advancement in the field of solar power allowed more
solar system usage than ever before. This trend is growing and solar systems are
becoming more and more popular and widely available every year now.
Major obstacle to faster development of the solar energy production was and still is the
cost of the equipment. This cost is rapidly decreasing, with increased efficiency and
better standards that are in use in the solar systems today. However, solar energy is still
not able to seriously compete with cost and amount of conventional power produced from
hydro, coal or nuclear power plants. Nonetheless, solar power is the power of the future,
with constantly increasing efficiency, generating capacity and rapidly decreasing costs.
Solar energy is widely used in the nature for a long time. Plants use it for the process of
photosynthesis; some of the animal species use it for the managing body temperature. It
is a natural way of providing light to earth.
Idea behind the conversion of the energy from the sun to the electricity is simple one.
Light waves from the sun are captured by solar panels where electric current is produced.
Process is as follows:
15
Light comes in the form waves from the sun to the earth. Waves are constructed out of
the tiny particles, called photons. Since they are moving in the waves and traveling
towards earth, photons carry kinetic energy and when they hit the solar panels they
transfer their energy to the valance electrons. Energy absorbed by the electrons make
them to move and soon after, valance electrons are leaving their positions, creating flow
of the current.
However, size wise, a photon is much smaller than an electron. Therefore, a much larger
number of photons is needed to move the electron from its valance position. Simplified,
this means that the panel needs to be in good sunlight and angle of the impact needs to be
as close to the ninety degrees as possible for the best efficiency. If there is no sun light,
during night or cloudy day, there will be no electricity produced from solar system.
Figure 5: Typical solar roof design
The solar panel position is very important. Good sun tracking monitor that positions
panel towards the sun all the time greatly improves efficiency, but this device also adds to
the price. A solar panel that has been positioned at 15 degrees inclined towards south by
latitude in the fixed position will produce as much as 30% more energy than the
horizontally flat fixed panel and about 20% less than the panel with a sun tracking device.
Installation of such additional devices such as sun tracking device do increase the
efficiency and capacity of produced energy, but they also add to the price and the
complexity of the system. The economic wisdom of installing a sun tracking device will
be determined by comparing cost of device over the energy gained with it over life time
of the system. However, complexity of the system is more important aspect. Fixed
systems without tracking devices are usually more dependable and maintenance free.
They can withstand greater storms and winds up to 120 miles per hour. Therefore, almost
all of the systems installed today are fixed horizontal systems with certain degree of
inclination. Angle of inclination will depend on the geographical position. At the equator
there will be no angle and plate should be absolutely flat, which makes exactly 90
degrees, and best efficiency.
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Currently produced in the solar panel is the direct current, and to be used in the home, for
example, it needs to be converted to the alternating current. Inverter does this, which is
the next component in the solar system. There are different kinds of inverters offered on
the market today and they range in the price, relative to its size, capacity and efficiency.
Size of the inverter is determined by the amount of the energy that is produced by the
solar panels. If the panels are not able to produce rated value of the inverter, it is waste of
money to buy bigger inverter. Bigger area needs to be covered by solar panels or their
inclination needs to be adjusted. Efficiency of the inverter is very important since not
much energy is produced by solar panels and it needs to be conserved as much as
possible.
However, the sun does not shine 24 hours a day. Depending on the part of the year,
location, sun radiation and cloud index, approximations of solar energy can be made.
During a night or cloudy days, solar panels do not output any energy. To sustain the
needs, one more component is necessary in the solar system. That component is a battery,
and not just one, banks of the batteries. Again, depending on the size of the solar system,
appropriate size of the battery bank can be determined.
Figure 6: Components of the solar electric system.
Battery banks add extra cost to the already expensive system. They also add complexity
and maintenance cost over the period of time. This option is not absolutely necessary, but
is preferable to collect any excess energy produced by the solar panels during a day when
usage is not big and production exceeds the demand. If electrical power is not used
instantly, it is lost. This process of matching generation with demand is a load balance.
During a night and clouds there is no energy produced. By installing battery banks,
overall reliability of the system and operational time are greatly improved and any excess
energy produced can be used in time of need, such as during a night or longer periods of
the cloudy days.
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By adding all of the necessary components, system greatly suffers on the efficiency side.
It is important to state that in recent years advance of technology made solar systems
possible to at least effectively use, but still, overall efficiency of the system is somewhere
in the neighborhood of 10-15 %. This is constantly improving but it is still low to be
adequately competitive with other alternative or conventional sources.
However, no matter how much system is effective and how much it can save, one thing is
important. It is absolutely necessary to conserve energy. It is up to Eagle Bluff,
consumers, to use energy wisely and not waste it. Installation of the energy efficient loads
is one way to conserve. Use natural gas heating instead if electric heating. Do not use
electric heating and other heavy motor loads at the same time. Improve lightning
efficiency, by using more efficient neon lamps instead of conventional light bulbs.
In recent years awareness of the global warming prompted development of the alternative
sources in U.S. Now there are loans and certain government subsidizes to help and ease
the cost of the solar power. Over a million households around the U.S have installed solar
systems on their roofs and that number is growing every day. Due to deregulation, power
companies are obligated to by any excess energy produced form alternative sources, back
to the grid.
Still with all of the advancement, solar energy is still most the expensive. Cost of electric
energy produced by the solar system is around 25 cents per kilo Watt-hour which is about
3 times higher than the cost for conventional energy on national average. Of course this is
installation cost divided by the expectancy of life of the solar system. Maintenance and
running costs are almost zero, but initial investments are usually higher that average total
return over lifetime of the system which is usually around 20-25 years.
Installation cost is about 8-12 dollars per Watt, which is $8000-$12000 per kWh.
Government subsidizes for about 2-4 dollars per Watt on the installation cost but still
even with this help, for the decent 2.5 kW system installed in the home ballpark of
$20,000 needs to be devoted. System as this one installed in the Midwest, for example,
will save around 300 dollars per year in the energy cost. It is easy to see that in 20 years,
solar system is not even able to pay for itself.
However, solar energy is a way of investing into the future. It is good to have system like
this in case of power outage. With battery banks it makes truly remarkable back-up
system in case of emergency and it generates certain revenues.
It is more than evident that solar energy is the energy way of the future. Its impact that is
already done may not be so obvious, but people do depend on this kind of power. Cell
phones, GPS, satellite television is transmitted over satellites. However, satellites that
orbit around earth and are powered by the solar energy, because it is the best solution for
the situation. It is secure and constant source of the energy as long as the full view of the
sun is possible.
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Figure 7: Solar Application
Finding and implementing the ideas for the alternative energy sources for the Eagle Bluff
learning center in Minnesota, solar energy was one of the options. However, by studying
the load curve and average usage it become obvious that solar energy regarding for the
moment its cost, will not play any vital role in the energy needs of the learning center.
Wind and bio-thermal will have impact on the bills, and solar would do almost not
noticeable impact.
In the southern Minnesota sun radiation index is on yearly average about 4kWh/m^2/day,
taking that national average is about 6-7kWh/m^2/day, and in southern parts of U.S is
even close to 10kWh/m^2/day. This means that solar energy in this part of the country is
not very applicable, but it is possible. Cloud index is also above national. This means less
sunny days than on the national average. Winters are longer farther north from the
equator, the incident angle is getting smaller than 90 degrees which added to already low
efficiency of the system, and it makes clear why there are not many solar panels on the
Midwest roofs. All of those factors combined limit possibilities for the solar generation in
that area, and initial costs prevents any bigger developments.
However, solar energy generation is not entirely impossible at the Eagle Bluff learning
center site. As the mater of fact, there would be even better opportunity by displaying this
system as a learning objective than in generation purposes. Whole site would benefit
tremendously from the impact that students and teachers would have as the display of
value for the renewable energy. This would ignite students to think appreciate and
conserve energy. It would also increase awareness to the students of how hard is to
produce renewable energy.
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Eagle Bluff would benefit from additional power it gets but most of the credit would be
ability to show and explain to the students something that other schools are not able to.
After all this is the environmental learning center. Therefore, as a displaying purpose,
solar system should be used at the Eagle Bluff.
One thing is certain, renewable alternative energy is here to stay. It is the energy of the
future. Just the matter of time is before science and technology further increase capacity
and efficiency of the solar energy conversion. Prices will most certainly rapidly to
decrease just as they did in the past decades. All of those factors will contribute to fact
that solar energy will take us to the limits of our universe and on the other side provide
lightning and other needs in the future. It is clean, sufficient energy source. It does not
add to the green house gasses and global warming. The best of all, after installation costs,
it is absolutely free, with minimum close to zero maintenance requirements.
Fuel Cells
A fuel cell operates at an efficiency of 40-50%, significantly higher than conventional
power generators. A steam power plant is typically 35% efficient, while the efficiency of
an internal combustion engine in most vehicles is only about 15%. The Proton Exchange
Membrane (PEM) type fuel cell would be best suited for Eagle bluff. PEM fuel cells are
compact and produce a powerful electric current relative to their size. They operate at a
lower temperature (less than 100 degrees Celsius or 212 degrees Fahrenheit) which
allows for faster start-up and rapid response to changes in the demand for power (load
following).
Figure 8: Fuel Cell
20
The core of a PEM fuel cell consists of a membrane electrode assembly (MEA), which is
placed between two flow-field plates. The MEA consists of two electrodes, the anode
and the cathode, which are each coated on one side with a thin catalyst layer and
separated by a proton exchange membrane (PEM). The flow-field plates direct hydrogen
to the anode and oxygen (from air) to the cathode. When hydrogen reaches the catalyst
layer, it separates into protons (hydrogen ions) and electrons.
The free electrons, produced at the anode, are conducted in the form of a usable electric
current through the external circuit. At the cathode, oxygen from the air, electrons from
the external circuit and protons combine to form water and heat. PEM fuel cells use a
solid polymer membrane (a thin plastic film) as an electrolyte as opposed to a liquid or
high-temperature ceramic.
Figure 9: A single fuel cell membrane electrode
Hydrogen
Hydrogen flows through channels in flow field plates to the anode where the platinum
catalyst promotes its separation into protons and electrons. Hydrogen can be supplied to a
fuel cell directly or may be obtained from natural gas, methanol or petroleum using a fuel
processor, which converts the hydrocarbons into hydrogen and carbon dioxide through a
catalytic chemical reaction. This will obviously not be environmentally friendly, but at
the same time will be more cost-effective than the current system in use.
Membrane Electrode Assembly
Each membrane electrode assembly consists of two electrodes (the anode and the
cathode) with a very thin layer of catalyst, bonded to either side of a proton exchange
membrane.
Air
Air flows through the channels in flow field plates to the cathode. The hydrogen protons
that migrate through the proton exchange membrane combine with oxygen in air and
electrons returning from the external circuit to form pure water and heat. The air stream
also removes the water created as a by-product of the electrochemical process.
21
Flow Field Plates
Gases (hydrogen and air) are supplied to the electrodes of the membrane electrode
assembly through channels formed in flow field plates.
Fuel Cell Stack
In order to obtain the desired amount of electrical power, individual fuel cells are
combined to form a fuel cell stack. By increasing the number of cells in a stack will
increase the voltage, while increasing the surface area of the cells increases the current.
Amount of fuel used will depend on how many times they go to the back-up system per
year; this will depend on the wind speeds throughout the year.
Hydro
The hydro system that would most fit the Eagle Bluff need is a run-of-the-river hydro
project, in which a portion of a river's water is diverted to a channel, pipeline, or
pressurized pipeline (penstock) that delivers it to a waterwheel or turbine. The moving
water rotates the wheel or turbine, which spins a shaft. The motion of the shaft can be
used for mechanical processes, such as pumping water, or it can be used to power an
alternator or generator to generate electricity.
The amount of electricity a hydropower plant produces depends on two factors:
How Far the Water Falls
The farther the water falls, the more power it has. Generally, the distance that the water
falls depends on the size of the dam. The higher the dam, the farther the water falls and
the more power it has. Scientists would say that the power of falling water is "directly
proportional" to the distance it falls. In other words, water falling twice as far, has twice
the energy.
Amount of Water Falling.
More water falling through the turbine will produce more power. The amount of water
available depends on the amount of water flowing down the river. Bigger rivers have
more flowing water and can produce more energy. Power is also "directly proportional"
to river flow. A river with twice the amount of flowing water as another river can
produce twice as much energy.
A simple diagram of the system will look like this
22
Figure 10: Typical Hydro Design
Figure 11: Water Fall of a Hydro Plant
23
In order to calculate the amount of electricity the Root River can produce they need to
obtain the elevation drop (head) from the entry of the penstock to the exit. In addition we
needed to find the average river flow at spot in the river or one closest upstream and
extrapolate the data to that spot. The Root River data is shown in Appendix C. The
equation that engineers use to calculate the power generated is shown as the following
Power = (Height of drop in river elevation) x (River Flow) x (Efficiency) / 11.8
Table 5: Hydro facts
The electric power in kilowatts (one kilowatt equals 1,000 watts).
Power
Height of Dam The distance the water falls measured in feet.
The amount of water flowing in the river measured in cubic feet per
second. This data was extrapolated from Pilot Mound and found to be a
River Flow
yearly average of 162.5 cubic feet per second
How well the turbine and generator convert the power of falling water
into electric power. For older, poorly maintained hydro plants this might
Efficiency
be 60% (0.60) while for newer, well operated plants this might be as
high as 90% (0.90).
Converts units of feet and seconds into kilowatts.
11.8
For the Root River in the Eagle Bluff area, assuming they buy a turbine and generator
with an efficiency of 85%. Then the power for the river will be:
Average Power = (20 feet) x (162.5 cubic feet per second) x (0.85) / 11.8 = 234.11 KW
Peak Power = (20 feet) x (203.3 cubic feet per second) x (0.85) / 11.8 = 292.88 KW
The approximate costs involved with this project are as follows given the following
assumptions:
Capital cost $/kW: $1700-2300/kW cap.
Operation cost/kWh: (0.4¢)
Maintenance cost/kWh: 2 (0.3¢)
Total cost/kWh: (2.4¢)
Operating life: 50+ years
There is no water storage required because it is a run-of-the-river hydro plant
Microturbine
Microturbine generators can be divided in two general classes:
1) Recuperated microturbines, which recover the heat from the exhaust gas to boost
the temperature of combustion and increase the efficiency,
24
2) Unrecuperated (or simple cycle) microturbines, which have lower efficiencies, but
also lower capital costs.
The average microturbine costs $650-1000/kW
Most microturbines are considered not environmentally friendly because of the use of
non-renewable fuels
The benefits of the Micro Turbine are:
Extreme low emissions
The MicroTurbine has the lowest emissions of any non-catalyzed fossil fuel combustion
system: the NOx emissions (on natural gas) are as low as 9 ppm (about 10 gr/GJ)
Virtually maintenance-free
The MicroTurbine has only one rotating part, using innovative air bearing technology. So
the unit does not need an oil system or a liquid coolant system, so reducing drastically the
maintenance necessary.
Plug-and-play
Using smart power electronics the unit is ready to run when you connect the fuel line and
the power cables: no synchronization equipment, no electronic safety devices, no
transformer are needed! The unit can also be remotely monitored and controlled.
Compact and light
The Microturbine is about the size of a refrigerator and weighs roughly 500 kg.
Fuel diversity
The Microturbine can handle a wide range of fuels: natural gas, biogas, flare gas, wet gas,
propane, diesel, kerosene, etc.
Multi-pack capability
The product range consists of a 30 kW unit and a 60 kW unit. But the MicroTurbine has a
multi-pack capability (up to 10-pack units): so a 10-pack 30 kW system acts as one 300
kW unit.
Various applications
Applications like electricity (grid connected or standalone), power quality, resource
recovery (like waste gas to electricity), cogeneration, cooling, drying processes, direct
CO2 fertilization, hybrid electric vehicles (like busses), marine (like yachts), rental, etc.
With only one rotating part and no liquids for cooling or lubrication, the Microturbine
requires very little maintenance: the unit basically requires service once every 8.000
hours, so at continuous operation once a year. At the first service interval it's only
required to change-out the air and gas filter: this is a job of about 15 minutes. This makes
the microturbine a reliable power source, requesting little attention and causing very
limited down time.
25
Table 6: Microturbine facts
Microturbine Overview
Commercially
Available
Yes (Limited)
Size Range
25 ñ 500 kW
Fuel
Natural gas, hydrogen, propane, diesel
Efficiency
20-30% (Recuperated)
Environmental
Low (<9-50 ppm) NOx
Other Features
Cogen (50-80°C water)
Commercial Status
Small volume production, commercial prototypes
now.
Investment costs
650-1000 dollars/KW
Operational costs
.05-.08 KW/hr
Figure 12: Flow system for a microturbine
26
Figure 13: Microturbine system
Load Management
When considering different options for alternative energy sources for Eagle Bluff, there
must be a focus on the demand side of energy replacement as well. These options can be
a less costly way of lowering energy costs. Eagle Bluff is currently averaging about 7-8
cents per kWh. Under the current Tri County Electric Coop, Eagle Bluff has a program
called dual fuel. One way to take advantage of this program is through load control.
Load management is used during periods of peak load. Typically, Tri-County Electric’s
highest demand is on the coldest days of winter and the hottest days of summer when
electricity is used more for heating and cooling purposes. Dairyland Power Cooperative,
Tri-County Electric’s wholesale power supplier, operates a network of radio transmitters
which send out load-control signals. These signals are received by a special load control
receiver installed at a member’s home or business. The load management system is
flexible to allow for the most efficient use of the electrical system. For example, electric
water heaters can be controlled during morning and evening peak energy periods to
conserve energy. Rather than starting up a power plant for a short period of time or
purchasing more expensive power from another utility, electrical demand is reduced by
controlling water heaters. These energy efficient water heaters are large enough to
provide the customer with hot water during the control period. Participation of Eagle
Bluff in the load management programs will reveal future savings by reducing energy
costs, and rebates are available for energy efficient water heaters. They are also helping
to reduce future energy costs by deferring construction of costly new power plants.
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The duel fuel heating system provides cost savings and comfort. With dual fuel, electric
heat is combined with a fossil fuel or storage heating system. The electric heat source is
used as the primary source to heat the customer’s home. During peak use periods, a load
management receiver switches the system to the backup fuel system automatically. When
the peak period is over, the system is automatically switched back to the less expensive
electric heating. In order to participate in the dual fuel program, the functional backup
heating system must be automatic and capable of heating the entire house or structure
during load control periods. The backup heating system should also have an adequate
supply of fuel during these periods. Electric heat can be interrupted at anytime during the
day or night to manage the system peaks.
There are several options that Eagle Bluff can choose from if they decide to install a dual
fuel system. With a forced air system, they can add an electric plenum heater or an air
source heat pump. Hot water systems can be converted by adding an electric boiler. There
are several options and many types of equipment that could qualify them for low dual
fuel rates. There are some additional up front costs with the installation of dual fuel, but
being able to take advantage of the off-peak electric rates will quickly make up for the
additional costs. Benefits include cost savings of as much as 40% or more, reliability and
heating system choice.
With the market instability of fossil fuels, many electric consumers are installing electric
heating equipment that is separately metered and has an automatic backup system of fuel
source or heat storage qualifies for the dual fuel rate. A dual fuel heating system
provides cost savings and comfort. With dual fuel Eagle Bluff can combine their electric
heat with a fuel heating system such as propane, fuel oil or natural gas. The electric heat
is used as the primary source for heat. Tri-County Electric Cooperative's winter dual fuel
rate is currently at 3.5 cents per kWh. If Eagle Bluff installs a dual fuel system, not only
will they save on their heating costs, but also save on their water heating and central air
conditioning costs. If Eagle Bluff participates in the dual fuel program with an approved
system, they can witness reduced electric water heating costs of almost 50% during the
winter. In the summer months the dual fuel rate is 5 cents per kWh, which allows them to
take advantage of a 35% reduction in air conditioning and water heating.
Lighting
Controlling the light quality and quantity is also a factor in dealing with load
management. The standard for lighting in tube lighting at Eagle Bluff is tube fluorescent
lighting. By changing the type of light bulbs used, load for lighting can be reduced, as
well a fewer bulbs used for the same amount of lighting. The following chart will serve
as a cross reference for some calculations for replacing the current T8 with a General
Electric F30T8/WM
Example: Office building at Eagle Bluff
• 200 (3-lamp) fixtures with typical ballast
• 8¢ kWh
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• 4500 operating hours/year
Strategy: Relamp T8 fixtures with Extra Life (XL)
T8/WM lamp
Calculation: 200 x 3 lamps x $ 0.72 (4500 hours at $0.08)
$432.00 energy saved annually
$2,400 energy saved over lamp life per lamp
(25,000 hours)
Table 7: Single Lamp Relamp
The GE F32T8 is a High Lumen lamp has 9% more lumens vs. the standard T8 (3100 vs.
2850). By increasing the ballast factor or choosing a more efficient fixture, it is possible
to remove one lamp per fixture at Eagle Bluff. That’s 32 W per fixture. This will allow
Eagle Bluff to use one less light bulb per fixture. This will involve improving the above
General Electric F30T8/WM with the GE F32T8. The difference in this model is the
need for a ballast upgrade, which will increase initial costs. The following is a
calculation used for the costs after initial costs by using a 3-lamp F32T8 (N) High Lumen
instead of a 4-Lamp F32T8 (L)
Example: Office building at Eagle Bluff
• 200 fixtures
• 8¢ kWh
• 4,500 operating hours/year
Strategy: Reduce energy costs by choosing a High Lumen 3-lamp fixture vs. a standard
4-lamp F32T8
Calculation: 200 x 3-lamps x $5.40 (4500hrs@$.08)
Outcome: 9% less lumens than an F32T8 (L-ballast)
$3240 energy saved annually
$20,880 energy saved over lamp life
(29,000 hours)
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Table 8: 4 vs. 3-Lamp
All of these cost saving are done by just changing to different light bulbs or the second
process of changing the light bulbs and the ballast.
Heat Pumps
The third main way of load management is heat pump implementation. Three terms are in
use to describe the technology in general: geothermal heat pump (GHP), geo-exchange
(GX) and ground-source heat pump (GSHP). The first two are typically used by
individuals in marketing and government, and GSHP by engineering and technical types.
The terms appearing in bold in the figure to the right will be the ones used throughout
this text. Ground-coupled systems have been widely used since the mid-1980s. Currently,
horizontal systems constitute about half of the installations, vertical 35%, and pond and
"other" approximately 15% (Kavanaugh, 1995). Groundwater systems have been used
for somewhat longer than ground-coupled systems, and have been popular since the early
1970s. One system type not shown in the figure is the standing column system, an
alternative type of open loop system. In this system, water is pumped from a well, passed
through the heat pump and returned to the same well. These systems have been widely
used in New England and were developed for areas in which the well will not produce
enough water for a conventional open- loop system. Sometimes a small flow of water
must be "bled" off to waste to keep the well temperature from getting too high or low.
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Figure 14: Geothermal Pumps
Heat naturally flows "downhill", from higher to lower temperatures. A heat pump is a
machine which causes the heat to flow in a direction opposite to its natural tendency or
"uphill" in terms of temperature. Because work must be done (energy consumed) to
accomplish this, the name heat "pump" is used to describe the device. In reality, a heat
pump is nothing more than a refrigeration unit. Any refrigeration device (window air
conditioner, refrigerator, freezer, etc.) moves heat from a space (to keep it cool) and
discharges that heat at higher temperatures. The only difference between a heat pump and
a refrigeration unit is the desired effect--cooling for the refrigeration unit and heating for
the heat pump. A second distinguishing factor of many heat pumps is that they are
reversible and can provide either heating or cooling to the space.
One of the most important characteristics of heat pumps, particularly in the context of
home heating/cooling, is that the efficiency of the unit and the energy required to operate
31
it are directly related to the temperatures between which it operates. In heat pump
terminology, the difference between the temperatures where the heat is absorbed (the
"source") and the temperature where the heat is delivered (the "sink") is called the "lift."
The larger the lift, the greater the power input required by the heat pump. This is
important because it forms the basis for the efficiency advantage of the geothermal heat
pumps over air-source heat pumps. An air-source heat pump must remove heat from cold
outside air in the winter and deliver heat to hot outside air in the summer. In contrast, the
GHP retrieves heat from relatively warm soil (or groundwater) in the winter and delivers
heat to the same relatively cool soil (or groundwater) in the summer.
As a result, geothermal heat pump, regardless of the season is always pumping the heat
over a shorter temperature distance than the air-source heat pump. This leads to higher
efficiency and lower energy use.
The cost that is saved with using a heat pump can amount to the following
Commonly used heating fuels have the following approximate heating content:
Fuel oil - 138,000 Btu/gal
Propane - 90,000 Btu/gal
Natural gas - 100,000 Btu/therm (1,000 Btu/ft3)
Electricity - 3,413 Btu/kWh
A common index of the cost of heat is "$ per 1,000,000 Btu of useful heat." In order to
calculate useful heat (heat actually delivered to the house), it's necessary to adjust for the
efficiency of the heating device and the cost of the fuel. The following equations can be
used for this purpose:
Table 9: Efficiency of different approaches
Fuel oil
7.25 x $/gallon
efficiency
Propane
11.1 x $/gallon
efficiency
10.0 x $/therm
efficiency
293 x $/kWh
Natural gas
Electric
resistance
ASHP
293 x $/kWh
COP
GHP
293 x $/kWh
COP
32
Efficiency
Old - 0.65
New std. - 0.78
Moderate - 0.84
High - 0.92
COP
Warm climate - 2.5
Cold Climate - 1.8
COP
Warm climate - 3.9
Cold Climate - 3.1
For example, let's look at Eagle Bluff which has a moderately cold climate when the fuel
costs are as follows, these costs are approximate, since the heating amount for Eagle
Bluff was not known at this time and costs vary at different times so the following costs
were chosen. Electricity at $0.07/kWh, fuel oil at $1.05/gal, propane at $1.20/gal, and
natural gas at $0.60/therm. This would result in the following useful heat costs:
Table 10: Fuel Costs
$ per Million Btu
9.06
15.86
7.14
20.51
9.54 (2.15 COP)
5.86 (3.5 COP)
Fuel oil
Propane
Natural gas
Electric resistance
ASHP
GHP
The typical installation costs range for different climates below is a chart showing the
installed cost for Minnesota’s area $/ton for a ground loop ground loop portion of the
system. For groundwater systems, the costs shown include the cost of a larger well pump,
tank, piping to and from the house, and a 50 ft disposal well. For ground-coupled
systems, the costs include the trenching or boring, pipe installation and headers up to the
home. This could be considered the "outside" the home costs for the system.
Figure 15: Installed Cost
33
The initial costs in the installation of any type of load management device will be higher
than the normal installation cost, but in the long run Eagle Bluff will benefit for
considering any load management tool in their future consideration for alternative energy.
E. Recommended Design Approach
After careful study of the previously described resources, it is recommend that a
detailed plan be developed which uses wind turbines and biothermal generators in
with a grid backup, to supply Eagle Bluff’s energy needs. All of the other
investigated resources should be noted in the final report with an explanation
concerning why they do not meet Eagle Bluff’s needs. There are number of
reasons for this recommendation
Reasons for wind and biothermal
The following is the reason for wind and biothermal:

Wind should be investigated further because initial calculations have
shown that will be able to produce enough energy to meet Eagle Bluffs
needs. Also investment costs are low compared to many of the other
sources.

Biothermal should be considered because a steady backup is needed so
that energy can be supplied when the wind is not blowing. Also the
investment costs are low when compared to the alternatives.
Reasons for Ending further development of the other sources
The following are reasons for ending development of the other resources:

Hydro is not politically feasible because the existing plan is an historical
land mark and the water tunnel contains rare bats. The investment cost of
developing a new site and tunnel are too high.

Solar would be quite useful as a renewable demonstration but the
investment cost needed to make solar a substantial energy sources is to
high.

Fuel cells require a high investment cost and they would only be useful for
energy storage. This causes the cost per kW to be quite high.
34

Micoturbines are highly efficient and would be useful as a replacement for
Eagle Bluffs’ gas fired generator. However, the turbine must be discarded
as a possible solution because it does not meet the criteria of being a
renewable energy source.
F. Detailed Design
A design must be developed that uses wind as the primary design and biothermal as the
best alternative back-up. In creating this design there are a number of points that must be
considered:






Current system
Break-even cost
Technical specifications of the proposed design
The complete system
Data uncertainty
Team recommendation
Each of these points will be examined and the results of a wind and biothermal combined
plan will be shown. Also, recommendations which consider the studies findings will be
considered.
Current System
The current system includes the utility’s system configuration and Eagle Bluff’s electric
usage. These issues are discussed in further details below
Current Utility Configuration
Data concerning the current utility configuration was provided by Tom Nigon of
PowerPlus Engineering. The system which serves Eagle Bluff has 3.9 miles 1/0 ACSR
3-phase overhead followed by 1.0 miles 1/0 Aluminum underground 3-phase cable.
Currently the maximum load on the 3-phase line is 2200 kW. For purposes of this study,
it is safe to assume that the system can handle up to 1 MW of added generation.
The current system meets Eagle Bluff needs using 4 transformers. The transformer sizes
are:
 1 – 3 phase 208Y/120 volts 300 kVA
 1 – 3 phase 208Y/120 volts 150 kVA
 1 – 1 phase 240/120 volt transformers rated 15 kVA
 1 – 1 phase 240/120 volt transformers rated 25 kVA
Figure 16 shows a one-line diagram of the current system
35
Peterson Circuit 4
5250 kVa
Transformer
3 miles of Overhead 1/0 ACSR
1 mile of
Underground 1/0
Aluminum
Eagle Bluff Facilites
The facilites have 4 transfomers
Overhead 1/0 ACSR
1-300kVA
1-15kVA
Underground 1/0 Aluminum
1-150kVA
1-25kVA
Transfomer
Figure 16: One-line diagram of the current system
Current Load Usage and Billing
Eagle Bluff’s billing data spanning from 11/10/01 to 8/10/03 were collect and studied so
that an understanding of the facilities usage could be obtained. For each month, bills
from four different meters were examined: the House’s meter, the Shiitake building’s
meter, the Campus’s meter, and Schroeder building’s meter. These bills were examined
for a number of values:
 Base cost
 Cost per kWh with the base cost
 Cost per kWh without the base
 Average kW usage, max usage
 Average yearly cost.
From these usages and costs, averages where obtained which were used to estimate total
yearly costs and usages. The billing information for each meter is summarized below.
The complete billing information can be found in Appendix B.
Campus Building
The Campus accounts for 80% of the total load and 71% of the yearly bill. Because of
the campus’s high usage the utility Tri-County Electric Cooperative, has installed a
demand meter. This meter is useful because it allowed the load factor of the Campus to
be calculated. This load factor was calculated to be an average of 38.4%. The monthly
campus load factor was applied the entire facility to obtain an estimate of Eagle Bluff’s
peak usage.
36
Table 11: Campus electrical energy facts
Average
kW
50.52
Peak kW
229
Campus
Base
$/kW with Base
Cost
Cost
$225.00
$0.053
$/kW w/o Base
Cost
$0.047
House Building
The House accounts for 2.8% of the load and 4.2% of the yearly bill. Three of the bills
examined had recalculated numbers. This meant the utility did not take a reading for that
month but calculated it from previous year’s usages. In this situation, the usage was
determined by using the calculated cost per kWh for the surrounding months and
applying it to the utilities calculated cost. Because of the House’s low usage this estimate
was satisfactory. The peak load of the house was obtained using the load factor obtained
for the Campus.
Table 12: House electrical energy facts
House
Average
kW
1.74
Estimate
Peak kW
9
Base
Cost
$18.70
$/kW with Base Cost
$0.089
$/kW w/o Base
Cost
$0.074
Shitake Building
The Shitake accounts for 1.2% of the load and 2% of the yearly bill. Four of the bills
where missing. For calculations involving these bills, a estimate of 500kWhs was used.
This was based on the fact that Shitakes average monthly usage is 472kW with out these
bills. As in the case of the House, the peak load was obtained using the Campus’s load
factor.
Table 13: Shiitake electrical energy facts
Shiitake
Average
kW
0.65
Estimated
Peak kW
4
Base
Cost
$18.70
$/kW with Base Cost
$0.116
$/kW w/o Base
Cost
$0.077
Schroeder Building
Next to the Campus, Schroeder is the largest consumer of power. The Schroeder meter
accounts for 16% of the load and 22.8% of the yearly bill. As in the case of the House
and the Shitake, the peak demand was calculated using the Campus load factor.
37
Table 14: Schroeder electrical energy facts
Schroeder
Average
kW
9.97
Estimated
Peak kW
49
Base
Cost
$120.50
$/kW with Base Cost
$0.086
$/kW w/o Base
Cost
$0.069
Total Facility
Using the bills from each building and the calculations a set of values where obtained that
would usage yearly usage estimates to be made.
Table 15: Entire Facility electrical energy facts
Est Avg
kW Usage
60
Est Yearly
Usage (kWh)
525600
Entire Facility
Est Yearly
Monthly
Cost
Base cost
$31,536.00
$382.90
Yearly
Base cost
$4,594.80
Avg $/kW
w/o base
$0.052
Avg $/kW
with base
$0.06
Technical Specifications of the Proposed Design
In-order to provide Eagle Bluff with alternative energy resources, a number of physical
components that need to be presented. These components fall within two areas:
 Generation
 Interconnection
Generation
The cost and power output capabilities of the chosen wind and biothermal generating
resources determine what the cost of producing energy will be with the new design. The
investment and operational costs along with the power outputs for the Fuhrlander 250kW
wind turbine and for the BioMax biothermal generator are discussed in the tables below.
The investment costs include all the necessary utility interconnect costs.
Table 16: Wind generation costs
Wind
Size (2-250kW turbines):
Lifetime (years):
Installation Cost:
Operation and Maintenance ($/kWh)
Yearly kWh output
Annual Cost (6% interest)
Cost ($/kWh)
500
25
$1,000,000.00
$0.01
500,503
$77,653.94
$0.17
38
Table 17: Biothermal generation costs
Biothermal (assuming no fuel cost)
Size(kW):
Lifetime (years):
Installation Cost:
Operation and Maintenance ($/kWh)
Yearly kWh output
Annual Cost (6% interest)
Cost ($/kWh)
30
25
$60,000.00
$0.085
262800
$26,696.93
$0.19
Interconnection
The interconnection between the utility and the generation is critical. There are number of
rules, regulations and costs involved in the inter-tie system. These costs are included in
the total installation cost estimates for each generation resource previously discussed. The
discussion of the interconnection includes the following:
 Legal Regulations and Insurance
 Technical Guidelines and Equipment
Legal Regulations
Interconnection of the electrical grid is a complicated issue, with technical standards that
need to be followed. This includes a proposed interconnection process for distributed
generation. It is necessary to stress that some of these issues are not completely resolved
yet, but are still very critical to the system.
Insurance
In general, many utilities believe that some sort of the insurance coverage should be
included in the proposed interconnection agreement. As to what extent of the insurance
coverage is part of the premises is not completely resolved. For the system that is less
that 250 kW and bigger than 40 kW, liability of one million dollars should be sufficient.
For larger systems greater than 250 kW, two million or more is an acceptable amount of
liability per occurrence. These are the current industry standards with no solid regulations
enacted. Such general liability insurance shall include some coverage against claims for
damages from bodily injury, including wrongful death and property damage arising from
the operating of the generation system.
Proof of the insurance policy should be presented at the time of submitting application for
the interconnection, as well as any time that is asked from the applicant for proof to be
provided. Insurance should be provided at least 30 days prior to the start of initial
operation.
39
Table 18: Insurance compared to other states
The most important factor prior to any operation is the safety. To ensure proper levels of
safety, an applicant must get some sort of pre-certification. This means that
interconnection; wiring and all other elements that are part of this project must be
certified and then double-checked to ensure proper operational functionality. They also
have to comply with local and federal regulations and standards. When everything is up
to code then the operation of the generation facilities should proceed.
Required documents for the interconnection regulation
Documents will vary depending on the size and type of generation site, and whether there
will be sale of excess energy to the utility.
The table below shows necessary documents for the different types of interconnection.
40
Table 19: Generation Interconnection summary
1. Interconnection Process = “State of Minnesota Interconnection Process for
Distributed Generation Systems.”
2. State of Minnesota Distributed Generation Interconnection Requirements
3. Generation Interconnection Application
4. Engineering Data Submittal = The Engineering Data Form/Agreement.
5. Interconnection Agreement = “Minnesota State Interconnection Agreement for the
Interconnection of Extended Parallel Distributed Generation Systems with Electric
Utilities”
This document may also include:
MISO = Midwest Independent System Operator, www.midwestiso.org
FERC = Federal Energy Regulatory Commission, www.ferc.gov
PPA = Power Purchase Agreement.
Interconnection Technical Guidelines
Minnesota and Federal laws allow for individuals, companies, and private organizations
to install and connect private power generators to the power transmission system. If the
generating unit is less the 40kW in size the utility to which the generator is connected to
is required to pay the average selling price which is close to $0.06 per kWh. For units
over 40kW the utility is required to pay the avoided cost which is currently $0.022 per
kWh for Tri County Electric. Each Independent Power Producer (IPP) is required to
meet the utilities guidelines as long as they fall under the State and Federal laws. The
following summarizes Tri County’s interconnection guidelines:
 Feasibility Study
41
 Pre-Parallel Inspection
 Interconnection Setup
 Power Factor
 Metering
The complete guidelines can be found in appendix D
Feasibility Study
Eagle Bluff will be required to pay for a feasibility study to be performed according to
the utilities request. This study will examine the current distribution system to see if any
upgrades will need to be made in order to handle the new generation capacity. It will
look at the circuit capacity, loading, and the capacity of local lines and transformers. In
conjunction with this feasibility study a pre-parallel inspection will need to take place
before any generator is connected.
Pre-Parallel Inspection
The pre-parallel inspection will test all of the interconnection breakers and relays to make
sure the protection equipment operates according to operation specification given by TriCounty Electric. The utility must be notified of this inspection two weeks before it takes
place (see appendix D for more detail)
Interconnection Setup
Federal and state law approves of the connection of independent power producers to local
utilities. However when problems such as power outages occur with the utility’s system
serious damage can result to the utility equipment and to the IPP. Because of the
problems that can develop, the Institute of Electronics and Electrical Engineers in
conjunction with the industry standards is recommending that the customer owned
generation be disconnected from the utility. This generator must be disconnected as soon
as a problem occurs with either the utilities system near the generator or with the
customers system. In accordance with these recommendations, Tri-County requires the
generator to be disconnected immediately. The rules governing this disconnect are found
in appendix D in the guide for interconnection requirements. In order to protect the
generator and to meet their requirements the following equipment must be installed:


Manual Disconnect
Relay /Breaker
Manual Disconnect
The generator should have a manual disconnect which will manually and permanently
disconnect the generator from the utility. If the transformer is owned by the utility then
the disconnect will be between the transformer and the generator. If the transformer is
owned by Eagle Bluff then the disconnect should be between the utility and the
transformer.
Relay/Breaker
42
A relay is a device that will sense when the utility or generator is having problems and
will take the appropriate action. The relay will disconnect and reconnect the generator to
the system. There are a number of types of sensing that must occur in order to effectively
disconnect the generator for all problems. The relay should be able to act for
unacceptable changes in voltage and frequency. If the voltage become to high or low it
will damage the generator, protective equipment and other customers on the system.
Also, changes in frequency will cause clocks to be off and can damage motors and other
electronics. Along with acting for changes in voltage and frequency, the relays should be
able to help detect when the generator synchronized so that it can be connected to the
utility’s system. In the past these functions required many different types of relays but
new technology allows this to be performed by one unit. On such recommend unit it the
M-3410A inter-tie/generator protection relay from Beckwith Electric (see references for
more information regarding this relay). It costs $1,200 and it will meet all of TriCounties requirements and it will protect the generator. Two of these units should be
installed for each inter-tie connection in order to insure operation. If one unit fails the
second will back it up.
Power Factor issues
Tri-County Electric requires any generator over 50kW to operate close to unity power
factor. In order to meet this requirement, Eagle Bluff may need to install capacitor banks.
The cost of these banks will depend on the amount of correction needed. The system
study will be able to determine the amount of correction needed.
Metering
Tri-County requires two meters to be installed. One meter will measure the power
produced and the second meter will measure the power delivered to Eagle Bluff facilities.
The difference between the meters will be the power bought by Eagle Bluff from the
utility. The excess power produced will be sold back at the utility’s avoid cost of $0.022
per kWh. Eagle Bluff will need at least one meter for the wind turbine and one meter for
the biothermal unit. It is unclear if the meters currently measuring Eagle Bluff’s usage
will need to be replaced.
Final Plan
The following description of the final plan includes a 2 wind turbines with a biothermal
generator for back-up. The main components are summarized, their place in the final
plan is shown, and the overall costs are laid out.
Main Components
There are several components that will be included in the final plan. The main ones are as
follows:
 Generators
 Transformers
43
 Relays
 Manual Disconnect
 Meters
The location of these components in relation to the interconnection can be seen in Figures
17 and 18 below.
Generators
There are several options for generation sources. The least cost option considered is the 2
Fuhrlander 250kW 30m rotor. As requested by Eagle Bluff, the second option includes 2 wind
turbines with a biothermal back-up. The details of each resource can be found previously in the
report.
Transformers
The wind turbines will share a single transformer of 500 kVA. The biothermal unit will
need a transformer of 50 kVA Because of the high cost of transformers in general, this
report recommends that Eagle Bluff allow the utility to purchase and own the
transformer. The voltage levels fore each type of generation were not found in the
researched specifications.
Relays
Each generating resource will need a relay. Because of costs it is recommended that
digital relays be used. As stated previously, the M-3410A inter-tie/generator protection
relay from Beckwith Electric fulfills Tri-County’s requirements and is recommended for
use. The wind turbines will need two relays each and the biothermal unit will need two
relays. The second relay on each unit provides for backup incase on unit fails. The M3410 cost $1,200 each. These costs are included in the installation cost estimates for the
turbine and biothermal generator.
Manual Disconnect
Each interconnect point will require a manual disconnect to separate the generator from
the system. The size of these must meet the utility’s specifications.
Meters
Meters will be needed to measure the power produced as well as the power used. The
meter currently used may remain in place. However two additional meters will need to
be installed at each generation site.
44
Tri-County
Electric
Generator / Inter-tie
Protection Relay
Transformer
Meter
BioThermal
Manual
Disconnect
Switch
50 kVA
12.5/7.2 kV Primary
Secondary voltage
unknown. Generator
voltage level not
given by the
manufacturer.
Figure 17: One-line diagram of biothermal unit and the inter-tie
Tri-County
Electric
Generator / Inter-tie
Protection Relay
Transformer
Meter
Wind
Turbine
Manual
Disconnect
Switch
300 kVA
12.5/7.2 kV Primary
Transformer and
voltages sizes will
depend on the turbine
selected
Figure 18: One-line diagram of wind turbine unit and the inter-tie
45
Finalized Design
The finalized system will connect the generation resources directly to the utility through
the interconnection points. The facilities at Eagle Bluff will remained unchanged with
the power being delivered to the building from Tri-Counties distribution. Figure 19
Shows the finalize plan.
Wind
Turbine
Inter-tie
Peterson Circuit 4
5250 kVa
Transformer
Inter-tie
3 miles of Overhead 1/0 ACSR
Bio
Thermal
1 mile of
Underground 1/0
Aluminum
Eagle Bluff Facilites
The facilites have 4 transfomers
Overhead 1/0 ACSR
1-300kVA
1-15kVA
Underground 1/0 Aluminum
1-150kVA
1-25kVA
Transfomer
Figure 19: One-line diagram of final plan
Costs of the Final Plan
The following table demonstrates the expected outputs that will be gained from using a
combination of wind turbines with a biothermal generator. These estimates will be
revised as the details of the plan are further investigated. It appears that such a plan will
have an investment cost of $1,060,000 which will be spread out over a 25 year period.
The cost of the equipment will be offset by selling back the excess power at $.022 per
kWh. The income is low compared to the overall cost and will not play a large factor in
reducing the cost.
Table 20: Combined generation costs
Wind, Biothermal, and grid back up
Excess Power Sold Back(kWh)
Selling income ($.022/kWh)
Cost of being connect to the Utility
Total Annual Cost (includes investment costs)
Total Cost ($/kWh)
237,703
$4,754.06
$4,594.80
$104,191.62
$0.14
46
Data uncertainty
Because of time limitations, this study focused on the most probable wind conditions for
the area. However, a slight change of the current wind profile would have a significant
effect on the total power produced by the wind turbines. To give an idea of how the
yearly power output would change with the shift of wind, the current wind profile was
increased and decreased by 2 mph. The results are shown in the graphs below.
Wind speed vs. hours/year
800.0
700.0
600.0
Hours/year
500.0
400.0
300.0
200.0
100.0
0.0
-100.0
0
10
20
30
40
50
60
Wind speed, mph
Current wind profile for 2001
Wind profile shifted to the right by 2mph
wind profile shifted to the left by 2 mph
Figure 20: Shifted wind curves for 2001 wind profile
Yearly power output for each wind speed
30000
Yearly power output, kWh
25000
20000
15000
10000
5000
0
0
10
20
30
40
50
60
-5000
Wind Speed, mph
Yearly kWh for current wind profile
Yearly kWh for shifted to the right by 2mph
Yearly kWh for shifted to the left by 2mph
Figure 21: Yearly power output of the wind turbines with shifted wind profile for 2001
47
Discussion of Data
The plan shows that Eagle Bluff will be paying more for power than their current costs.
Eagle Bluff will be paying $0.14 per kWh verse the current cost of $.06 per kWh. The
cost per kW does not truly reflect the total costs. The power produce with proposed plan
is 763,303kWh verses the expected usage of 525,600kWh. However, the costs in the
plan do not include government grants, tax breaks, and donations. The estimates show
what the costs are if no aid is provided. However, with some wind change, the power
output would largely change. The following is a comparison of the Total net present
worth cost of the different wind profiles compared to the break even cost.
NPW break-even investment cost
=
$403,136
Net present worth cost (Current)
=
$634,566.24
Net present worth cost (Shifted to the right) =
$124,401.59
Net present worth cost (Shifted to the left) =
$905,130.99
As seen from the above data, the wind has a major role in determining whether the
project would be economically feasible or not.
Recommendation
After careful study of Eagle Bluff options with the current profile and load projections, it
is determined that the wind turbine was the best solution with a possible biothermal backup. If an alternative energy resource to be installed, 2 turbines would be the cheapest
with a project present worth cost of $634,566 for a 25 year span. With the addition of a
back-up thermal unit, the cost rises to $883,458. In order for these plans to be
economically competitive, they need to be less than or equal to Eagle Bluff’s break-even
cost of $403,136. Based on the fact that each plan will be more than the break-even cost,
this study concludes that alternative energy will only be economically viable solution if
government grants and outside donations are received. From the data presented above,
the project could become economically feasible if there was a better wind profile. The
team recommends that further wind studies be performed at optimal heights and locations
for the wind turbines placement. Such a study shows that alternative wind energy could
be a cost effective solution to Eagle Bluff energy needs.
48
Resource and Schedules
Resource Requirements
The resources to be used on this report are the gas money spent to make trips up to Eagle
Bluff. The other thing is the dollars spent on paperwork and copy materials. Weather
charts will be provided from the Minnesota state department as well as the wind tests
from the Eagle Bluff center itself. The team has a budget of $150.00 that the team will
not exceed in any circumstances. Table 14 and Table 15 show the estimated and actual
personal effort requirements. Chart 13 and 14 show estimated and actual hours spent by
each member of the group. The tasks in the Tables are as follows:





Task 1 – Problem definition
Task 2 – Technical implementation and considerations
Task 3 – System design
Task 4 – End product demonstration
Task 5 – Project reporting
Table 21: Personnel Effort Requirements
Original Individual Effort Requirements
Personnel Name
Abou Ardate, Abdul
Kader
Brokovic, Darko
Disenhouse, Daniel
Kirkpatrick, Lucas
Totals
Task
1
Task
2
Task
3
Task
4
Task
5
12
11
8
9
40
35
34
37
38
144
36
37
36
35
144
14
15
16
15
60
20
20
25
30
95
49
Totals
117
117
122
127
473
Table 22: Revised Personnel Effort Requirements
Revised Individual Effort Requirements
Personnel Name
Abou Ardate, Abdul
Kader
Brokovic, Darko
Disenhouse, Daniel
Kirkpatrick, Lucas
Totals
Task 1
Task
2
Task
3
12
11
10
12
45
57
49
54
60
220
36
37
36
35
144
Task 4
Task 5
Totals
14
15
16
15
60
20
20
25
30
95
139
132
141
152
564
Table 23: Final Individual Effort Requirements
Final Individual Effort Requirements
Personnel
Name
Abou Ardate,
Abdul Kader
Brokovic,
Darko
Disenhouse,
Daniel
Kirkpatrick,
Lucas
Task 1
Totals
Task 2
Task
3
Task 4
Task
5
Totals
12
57
40
17
20
146
11
49
35
9
20
124
10
54
33
9
25
131
12
60
34
10
25
141
45
220
142
45
90
542
50
Individual Estimated Time spent in Hours
117
127
Abdul Kader Abou Ardate
Darko Brokovic
Daniel Disenhouse
Lucas Kirkpatrick
117
122
Figure 22: Chart of Original Effort
Actual Time Spent in hours on Tasks 1,2,5
74
83
Abdul Kader Abou Ardate
Darko Brokovic
Daniel Disenhouse
Lucas Kirkpatrick
65
74
Figure 23: Chart of Updated Effort
51
Actual Time Spent(hours) on Tasks 1,2,3,4,5
140.75, 26%
145.6666667, 27%
KIRKPATRICK LUCAS J
DISENHOUSE DANIEL
BORKOVIC DARKO
ABOU-ARDATE ABDUL KADER
131.3333333, 24%
124.3333333, 23%
Figure 24: Actual Time Spent
Table 24: Estimated Financial Cost
Revised Estimated Financial Cost
Item
W/O LABOR
Material and Resources
a. Poster & misc
b. Trip Costs
Subtotal
WITH LABOR
$52.00
$50.00
$102.00
$52.00
$1,080.00
$1,132.00
$102.00
$1,431.70
$1,359.60
$1,452.30
$1,565.60
$5,809.20
$6,941.20
Labor at $10.30 per hour (separate from trip labor)
a.
b.
c.
e.
Abou Ardate, Abdul Kader
Brokovic, Darko
Disenhouse, Daniel
Kirkpatrick, Lucas
Subtotal
Total
52
Table 25: Revised Financial Cost
Estimated Financial Cost
Item
W/O LABOR
Material and
Resources
a. Poster & misc
b. Trip Costs
Subtotal
WITH LABOR
$65.00
$100.00
$165.00
$65.00
$2,160.00
$2,225.00
$165.00
$1,205.10
$1,205.10
$1,256.60
$1,308.10
$4,974.90
$7,199.90
Labor at $10.30 per hour (separate from trip labor)
a.
b.
c.
e.
Abou Ardate, Abdul Kader
Brokovic, Darko
Disenhouse, Daniel
Kirkpatrick, Lucas
Subtotal
Total
Table 26: Actual Estimated Project Cost
Actual Estimated Project Cost
Item
W/O LABOR
Material and Resources
a. Poster & misc
b. Trip Costs
Subtotal
WITH LABOR
$52.00
$50.00
$52.00
$1,080.00
$102.00
$1,132.00
Labor at $10.30 per hour (separate from trip labor)
a.
b.
c.
e.
Abou Ardate, Abdul Kader
Brokovic, Darko
Disenhouse, Daniel
Kirkpatrick, Lucas
$1,503.80
$1,277.20
$1,349.30
$1,452.30
Subtotal
$5,582.60
Total
$102.00
$6,714.60
Schedules
The technology investigated consumed more than the expected time that was originally
assigned, but the team was able to deliver results on schedule. It appears that the team is
53
on task for next semester. However, it is thought that the detailed project design will take
longer than expected.
Figure 25: Gant Chart of Projects and Deliverables
The breaks in the chart represent the following breaks in order Thanksgiving break,
winter break, and spring break. During these times there will be no deliverables
scheduled
Project EvaluationThe evaluation phase consists of meeting the project on time and at or under budget.
These were completed as per a successful project. More to be added later
54
Closure Material
Closing material of this project includes the following:
 Project Evaluation
 Recommendations
 Lessons Learned
 Risk and Risk Management
 Project Team Information
 Project Summary
 References
 Appendices
Project Evaluation
All research was completed. In evaluating the success of this project, it was determined
that all research was completed and a final plan was developed. The depth of the plan
was minimized when the time considerations were evaluated. All basic milestones were
met, all is left to be competed is the presentation to the review panel and the delivery of
the final report to Eagle Bluff.
Recommendations for Additional Work
Based on the findings of the report, it has been determined that future development by
other senior design teams should not continue. However, Eagle Bluff should investigate
their financial resources and consider further studies by consulting firms.
Lessons Learned
There were number of lessons learned throughout this study. Some of the areas in which
lessons were learned are:
 Alternative resources
 Load studies and load management
 Interconnection requirements and regulations
 Complexity of wind patterns
 Types of economic evaluation
 Team work and time management
It is not reasonable to describe all the knowledge gained in these areas. However, a
careful examination of the report will reveal the information learned.
Risk and Risk Management
The risks involved in this project were minimal the following is a list of some risks
involved
• Project scope
• Loss of team members
55
•
•
Loss of an advisor
Collection of information
The management of these risks can be balanced by the following
• Constant contact with advisors
• Bring in another advisor
• Collect information ahead of need date
Project Team Information
The following is a list of the contact information for the client, advisors and team.
1. Client Information
The following is the client’s contact information:

Eagle Bluff Environmental Learning Center
Executive Director: Jerome "Joe" Deden
1991 Brightsdale Road
Route 2, Box 156A
Lanesboro, MN 55949
Telephone number: 888-800-9558 (in Minnesota, Iowa, and Wisconsin)
Fax: (507) 467-3583
Email: director@eagle-bluff.org
2. Faculty Advisor Information
The following is the advisor’s contact information:

VENKATA S S
Office Address: 2211 COOVER
City/State: Ames, IA 50011
Office Phone: 515-294-3459
Home Phone: 515-292-3632
Fax: 515-294-3637
Email: venkata@iastate.edu

MCCALLEY JAMES D
Office Address: 2210 COOVER
City/State: Ames, IA 50011
Office Phone: 515-294-4844
Home Phone: 515-233-0280
Fax: 515-294-4263
Email: jdm@iastate.edu
56

DELLY OLIVEIRA
Visiting Professor in Power Engineering
Office Address: 1113 COOVER
City/State: Ames, IA 50011
Office Phone: 515-294-2072
Home Phone: 515-292-6262
Fax: 515-294-8432
Email: delly@iastate.edu
3. Student Team Information
The following is the team’s contact information:

ABOU-ARDATE ABDUL KADER F
Major: Electrical Engineering
Univ Address: 102 OAK BLVD #308
City/State: HUXLEY IA 50124
Phone: 515-460-0857
Email: aboudi@iastate.edu

BORKOVIC DARKO
Major: Electrical Engineering
Univ Address: 3730 SKYLINE CIRCLE
City/State: DES MOINES IA 50310
Phone: 515-277-0383
Email: darko@iastate.edu

DISENHOUSE DANIEL MARK
Major: Electrical Engineering
Univ Address: 402 N MAIN ST BOX 185
City/State: ROLAND IA 50236
Phone: 515-388-4109
Email: daniel@iastate.edu

KIRKPATRICK LUCAS J
Major: Electrical Engineering
Univ Address: 1316 South Duff Trailer 11
City/State: AMES IA 50010
Phone: 712-420-1195
Email: lucask@iastate.edu
57
Closing Summary
It is important with the guidelines of Eagle Bluff that renewable energy resources be
considered. However, because of financial constraints, any energy plan must be
economically feasible. With these values in mind, all reasonable energy solutions were
investigated, and the most practical and economically viable solution was developed.
This solution determined that alternative energy would not be feasible without
government grants or donations. It was also discovered that if a small improvement in
the wind profile occurred, the project would become cost effective. These conclusions
show that the study has been beneficial both in the lessons learned by the design team and
the information provided to Eagle Bluff regarding their situation.
58
References
A. Hunter Fanney, Kenneth R. Henderson and Eric R. Weise. “Measured 35kW system
performance”, 2003
<http://www.bfrl.nist.gov/863/bipv/documents/35kw_HI.pdf>
American Wind Energy Association.
<http://www.awea.org/default.htm>
Arthur R. Bergen and Vijay Vittal. Power Systems Analysis. Prentice Hall: 1986, 2000.
Ballard Power Systems
<http://www.ballard.com/default.asp?pgid=1&dbid=1>
Beckwith Electric Co.
<http://www.beckwithelectric.com/relays/m3410/m3410a.htm>
Community Power Cooperation
11/18/03. <http://www.gocpc.com/default1.htm>
EE 303 Course Notes. Iowa State University, Department of Electrical and Computer
Engineering, Spring 2002.
Element 1 power systems
<http://e1ps.tripod.com/E1PSwebsite/id3.html>
Energy Research Center
<http://www.humboldt.edu/~serc/fc.html>
GE lightning, North America
<http://www.gelighting.com/na/institute/index.html>
Geo-Heat Center
<http://geoheat.oit.edu/>
Geveke Power Systems
<http://www.microturbine.nl/cases/casestudy.asp?caseid=8>
How A Hydroelectric Project Can Affect A River. Foundation for water and Energy
Education.
<http://www.fwee.org/hpar.html#ecosystem>
Inside Wind Turbines
<http://www.jxj.com/magsandj/rew/2003_01/inside_wind.html>
Isolation index by geographical location
59
<http://www.solarseller.com/solar_insolation_maps_and_chart_.htm>
Jarod Smeenk ISU Researcher. Personal Interview. 10/16/03
Larry Flowers. Wind Energy: Technology, Markets, Wind Energy: Technology, Markets,
Economics and Stakeholders, November 2003.
<http://www,windpoweringamerica.gov>
Links to solar related homepages
<http://www.montanagreenpower.com/solar/solarlinks.html>
ME3 - Sustainable Minnesota - Wind Energy Information.
<http://www.me3.org/issues/wind/>
Mozina, Charles. “Interconnect Protection of IPP Generators Using Digital Technology”,
Beckwith Electric Co.
Michael A. Klemen. AWH-FAQ Perfect Turbine, 2001.
<http://www.ndsu.nodak.edu/ndsu/klemen/Perfect_Turbine.htm>
Microturbines. California Energy Commission
<http://www.energy.ca.gov/distgen/equipment/microturbines/microturbines.html>
Minnesota Wind Sites.
<http://wind.undeerc.org/wind/MNwindsites.asp>
Monthly Streamflow Statistics for Minnesota
<http://nwis.waterdata.usgs.gov/mn/nwis/monthly/?site_no=05385000&agency_cd=USG
S>
National Renewable Energy Laboratory.
<http://www.nrel.gov/gis/wind_maps.html>
Prices on the costs and approximations of the costs for alternative energy sources
<http://www.jatsgreenpower.com/wpt-wind-generator.html>
Solar energy and how it works
<http://www.eia.doe.gov/kids/renewable/solar.html>
Solar radiation index by geographical location
<http://www.oksolar.com/technical/daiy_solar_radiation.html>
Sunshine Sensor type BF3
<http://www.delta-t.co.uk/frame/submenu/bf3.html>
60
Small Hydropower Systems, published in July 2001
<http://www.nrel.gov/docs/fy01osti/29065.pdf>
Ted Kjos of Tri County Electric. Phone interview. 11/3/03
Tri County Electric Cooperative
<http://www.tec.coop/services/incentives.shtml>
US Department of Energy. Energy Efficiency and Renewable Energy.
< http://www.eere.energy.gov/>
Wind Energy Manual.
<http://www.windpower.org/en/core.htm>
Wind Energy Manual, Iowa Energy Center, 2000
<http://www.energy.iastate.edu/renewable/wind/wem-index.html>
Wind Powering America
<http://www.eere.energy.gov/windpoweringamerica/pioneers_clark.html>
Wind turbines as distributed generation Energy. Wise News Issue 65, March 2000.
<http://www.eeca.govt.nz/content/EW_news/65mar00/65irl-wind.htm>
61
Appendix A – Wind Data
kW
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
31.0
32.0
33.0
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
45.0
46.0
47.0
48.0
49.0
50.0
0.0
0.0
0.0
0.0
0.0
0.0
0.5
2.1
4.8
8.6
16.8
25.0
29.5
34.1
43.7
54.6
67.7
82.3
97.5
113.9
130.3
145.0
160.0
173.6
187.3
200.2
212.9
220.7
225.3
229.8
234.4
239.0
244.0
249.0
251.7
301.4
69.5
170.5
269.9
273.1
277.7
284.5
290.8
294.9
299.0
299.5
299.9
296.7
292.6
289.1
285.9
Fuhrlaender 250 kW Wind Turbine Power Curve
Rotor: 30 Meters
350.0
Power Generated kW
mph
300.0
250.0
200.0
150.0
100.0
50.0
0.0
0.0
10.0
20.0
30.0
Wind Speed mph
A1
40.0
50.0
Vestas 660 kW Wind Turbine Power Curve
Rotor: 47 Meters
kW
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
31.0
32.0
33.0
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
45.0
46.0
47.0
48.0
49.0
50.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.3
3.6
19.7
35.7
56.2
76.6
102.0
128.6
159.2
192.4
227.7
265.9
304.0
346.3
387.9
427.9
467.9
503.1
537.1
565.5
590.2
610.6
624.7
637.5
644.7
652.0
654.3
656.8
657.7
658.6
659.5
660.0
660.0
660.0
660.0
660.0
660.0
660.0
660.0
660.0
660.0
660.0
660.0
700.0
Power Generated, kW
mph
600.0
500.0
400.0
300.0
200.0
100.0
0.0
0.0
10.0
20.0
30.0
40.0
Wind Speed, mph
50.0
60.0
Micron 750 kW Wind Turbine Power Curve
Rotor: 48 Meters
kW
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
31.0
32.0
33.0
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
45.0
46.0
47.0
48.0
49.0
50.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.5
12.4
22.6
37.8
53.1
73.2
93.4
118.5
144.8
179.7
220.2
263.6
311.2
358.7
410.8
462.2
508.7
555.1
592.1
626.7
655.7
681.1
702.4
717.6
731.2
738.4
745.5
747.5
750.5
748.0
745.6
741.9
737.5
732.7
727.3
722.0
716.9
711.9
707.1
702.4
698.8
695.6
693.9
693.2
800.0
Power Generated,kW
mph
700.0
600.0
500.0
400.0
300.0
200.0
100.0
0.0
0.0
10.0
20.0
30.0
40.0
Wind Speed,mph
50.0
60.0
Mitsubishi 1000 kW Wind Turbine Power Curve
Rotor: 56 Meters
kW
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
31.0
32.0
33.0
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
45.0
46.0
47.0
48.0
49.0
50.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
4.2
14.6
26.2
42.1
58.0
85.3
112.5
145.3
179.4
224.4
276.6
333.1
395.8
458.5
527.3
595.0
664.5
734.1
793.8
851.1
901.8
948.2
980.4
991.3
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1200.0
Power Generated,kW
mph
1000.0
800.0
600.0
400.0
200.0
0.0
0.0
10.0
20.0
30.0
Wind Speed,mph
40.0
50.0
kW
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
18.0
19.0
20.0
21.0
22.0
23.0
24.0
25.0
26.0
27.0
28.0
29.0
30.0
31.0
32.0
33.0
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
45.0
46.0
47.0
48.0
49.0
50.0
0.0
0.0
0.0
0.0
0.0
0.0
7.3
19.8
29.4
42.7
71.4
100.0
136.8
173.6
219.5
267.7
332.0
407.0
487.1
574.8
662.5
762.8
861.0
924.2
987.4
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
1000.0
Suzlon 1 MW Wind Turbine Power Curve
Rotor 64 Meters
1200.0
Power Generated,kW
mph
1000.0
800.0
600.0
400.0
200.0
0.0
0.0
10.0
20.0
30.0
Wind Speed,mph
40.0
50.0
Sample of Wind Speed Statistics: 7/4/2003 - 8/4/2003
Description
Average
Max | Min
WS30W
mph
7.19
24.73 | 0.22
Minnesota Wind Sites
Sample of Wind Speed Statistics: 1/1/2001 - 4/1/2001
Description
Average
Max | Min
WS30W
mph
8.22
24.04 | 0.25
Minnesota Wind Sites
Appendix B – Load Data
B1
Appendix C – Hydro Data
The following table is monthly downstream monthly data used to get a yearly average
upstream
387 451 1,015 1,344 2,279 989 844 959 685 555 1,440 1,671
1991
1992
770 692 2,140 2,062 1,179
844
785
640
1993
569 448
1994
602 740 1,321 1,271 1,100
857
773 1,082
1995
305 538 1,348 1,702 1,179
961
817
1996
439 697 1,700
627 1,260
1997
446 481 2,415 1,331
933
1998
461 982 1,129 1,482
1999
2000
885 655 1,079
920 4,325 1,960 2,665 2,112 2,257 1,303 922
767
798
737
726 798
657
471
763
639 586
564
455
685
498
439 416
475
484
687 1,221
864
700 691
550
480
870 1,584 1,589 1,061
710 793
897
631
610 852
881 2,520 1,876 1,239 1,840 1,722
941 732
655
564
492 856
798
987
760
667
576 521
520
435
849
601 1,403 4,389 2,658
90 year
Mean of
414 501 1,395 1,201
monthly
streamflows
845
948
C-1
834
Appendix D – Tri-County Interconnection Guidelines
TRI-COUNTY ELECTRIC COOPERATIVE
GUIDE FOR INTERCONNECTION REQUIREMENTS AND
PARALLEL OPERATION OF CUSTOMER-OWNED GENERATION
1.0
Technical and Protection Interconnection Requirements
This standard provides the technical and protection specifications and requirements for
the interconnection of electrical generation facilities, owned and operated by Qualifying
Facilities and small power producers (QFs), to Tri-County Electric Cooperative’s
(TEC’s) distribution system. These requirements apply to QFs with an aggregate
capacity greater than 40 kW and less than 1,000 kW. Additional technical requirements
may be necessary for some limited situations.
1.1
Feasibility Study
Depending on the size of the generator and the qualities of the local distribution
feeder near the interconnection point, a feasibility study may be necessary to review
the impact the proposed interconnection will have on TEC’s system. The generator
manufacturer’s data sheets and protective device characteristics must be made
available to review the affect the facility will have on the distribution system.
1.1.1
Special Facilities
The feasibility study will identify if any additions or modifications to the distribution
system will be necessary. These special facilities could include a line extension to the
generator site, existing line reinforcement, protective device modifications, and
regulator setting modifications. The QF will be responsible to pay TEC the installed
cost of any special facilities provided in advance. This charge may be amortized over
a period and at an interest rate to be determined on an individual basis.
1.1.2
Metering
Two meters will be required, one to measure the net generation output from the QF
and one to measure the power delivered by TEC to all other load on the QFs
premises. The QF will shall pay for the meter to measure net generation as special
D-1
facilities and shall provide, install, own, and maintain all mounting structures,
conduits, meter sockets, and meter socket enclosures for both meters.
1.2
Operating Limits
In order to minimize adverse operating conditions of electric service provided to other
TEC customers, the QF’s generation operating in parallel with TEC’s distribution
system shall meet the following operating criteria:
1.2.1
Voltage
The QF shall not degrade the voltage provided to other TEC customers to service
voltages outside the limits (low = 114 volts, high = 126 volts on a 120 volt base) of
ANSI C84.1, Range A. The generator shall also be capable of tolerating steady-state
voltage fluctuations of +/- 5% of the nominal voltage. The QF can use automatic
voltage regulation when such regulation can be accomplished without detriment to
the TEC system.
1.2.1.1 Voltage Disturbances
The protection function of the over/under voltage relay shall measure the RMS
voltage of each phase to ground and disconnect the generator from the TEC
distribution system within the clearing time indicated below. Clearing time is the
time from the start of the abnormal condition and the breaker operation that will
separate the QF’s generator from the distribution system. The voltage set points will
be field adjustable.
QF System Response to Abnormal Voltages (120 V base) *
Voltage Range (Volts)
Clearing Time (sec.)
V<60
0.16
60≤V<106
1
132<V<144
1
144≤V
0.16
* The TEC system operator can specify different voltage settings or Trip Times to accommodate
system requirements.
1.2.2
Flicker
The QF shall not produce objectionable flicker levels to neighboring TEC customers.
The QF shall be responsible for corrections if their generator produces such flicker.
1.2.3
Frequency
Over and under frequency protection is important in the prevention of islanding
the QF’s generation.
Frequency
QF Separation Time
> 60.5 Hz
0.16 sec.
59.3 – 57.0 Hz
Time Delayed *
<57.0 Hz
0.16 sec.
*The default for this frequency range shall be 0.16 seconds but can be adjusted at
the request of the TEC operator.
1.2.4
Power Factor
The QF shall operate as close to unity power factor as possible. For QFs with a rated
capacity over 50 kW, TEC shall reserve the right to require the QF to correct their
power factor to unity or reimburse TEC for its cost to install the necessary kVARs.
1.2.5
Synchronization
The QF shall provide tests to verify that the interconnection system shall not connect
the generator to the utility unless the following conditions are satisfied.
Synchronization Parameter Limits for Synchronous Generator
Aggregate Rating
of QF Units
Frequency
Difference
Voltage
Difference
Phase Angle
Difference
(kVA)
(Δf, Hz)
(ΔV, %)
(ΔΦ, °)
0 – 500
0.3
10
20
500 - 1000
0.2
5
15
Self-excited induction generators shall be tested as per above table. Other
induction generators shall be tested for startup current using the Locked-Rotor
Method test procedure defined in NEMA MG-1 (manufacturers data is
acceptable, if available).
1.2.6
Overcurrent
The QF shall automatically disconnect itself from TEC’s system when faults occur on
the feeder it is connected to.
Protective Devices
1.3.1
Disconnect
The QF shall supply a readily accessible, lockable, visible-break, gang operated, loadbreak isolation device located such that the generator and all protective devices and
control apparatus can be disconnected entirely from the utility system.
1.3.2
Relays
Protective relays that sense over/under voltage, over/under frequency, and phase and
neutral overcurrent conditions and will cause the interrupting device to isolate the
QF’s generator from the distribution system shall be installed. If the QF will not be
selling power to TEC, a reverse power relay will need to be installed. Test reports on
each component shall be provided to TEC. These tests may be performed in the
factory, at a testing laboratory, or with testing equipment in the field.
1.3.3
Breaker
The QF shall have an interrupting device, sized to meet all applicable local, state, and
federal codes, that will initiate a disconnect sequence as the set points defined above
are reached.
A failure of the QF’s interconnection protection equipment, including loss of
control power, shall open the interrupting device to disconnect the generator from
TEC’s system.
1.3.4
Single Phase Devices
The circuit protection on the distribution line that the QF interconnects to may be
performed by single phase devises. Their operation due to fault conditions could
result in one or more of the phases becoming de-energized. This requires that the QF
install voltage, frequency and phase overcurrent relays on all three phases so they
sense abnormal conditions when they occur on a single phase and provide a
disconnection signal to the interrupting device.
Automatic Reclosing
Experience has shown that 70 to 90 percent of line faults are temporary in nature
if the faulted line is quickly disconnected from the system. The single phase
protection covered in 1.3.4. takes advantage of this occurrence by going into a
trip-reclose sequence to restore service if the fault is no longer present. For radial
feeders the initial attempt is followed by one to three more time-delayed attempts
before locking out. The time delay between between tripping and the initial
reclose attempt by the substation breaker or line recloser can range from 0.25
seconds (15 cycles) to several seconds. For most TEC protective devices the
reclosing time is 1 to 1.5 seconds. The undervoltage relay of the QF has to
recognize that the feeder has tripped and isolate the generator from the system
before the initial reclosing takes place. Otherwise, the QF generator may have
lost synchronism with the system at the first reclose possibly resulting in damage
to either system. This accounts for the undervoltage response times listed in
Section 1.2.1.1.
The QF must remain isolated from the distribution system for 5 minutes to allow
the system protective devices to reset after tripping.
1.4
Monitoring
If the QF has a unit of 250 kVA or larger, or an aggregate of 250 kVA or more at a
single interconnection point, provisions for monitoring selected operating parameters
at the point of interconnection may be required.
1.5
Pre-Parallel Inspection
Prior to the actual operation of the QF generator in parallel with TEC’s
distribution system, the QF shall provide factory tests of all protective devices at
their desired settings or perform field tests at these settings by secondary injection
or applied waveforms to assure proper operation.
All interconnection protective devices shall be trip tested to prove that the
appropriate interrupting device open when the protective device operates. An
inspection shall be performed to verify:

that all protective relays are at their required settings.

that proper voltages and currents are applied to the protective devices.

that the synchronizing equipment functions properly.
The voltage flicker at the interconnection point shall be measured and recorded
during interconnection.
TEC must be provided a two week notice before these tests and inspection is
performed. They will have the option of having a representative attend to witness
the preparallel inspection.
Once the QF is interconnected, TEC shall have the right to inspect or have
additional tests run if the facility is suspected of causing adverse operational
effects to its distribution system.