Common Sense Approaches to
Saving Energy and Money
Conrad Meyer
Technical Manager - WRP
Improving Energy Management
• Tracking and Understanding Energy Use
– Electric Utilities Terms & Rates
– Energy Baselines
– Benchmarking Energy Use and Performance
• Energy Assessments
– Energy Use by Area
– Common opportunity Areas
– Technical & Financial Analysis
– Help and Resources
Benefits of Tracking Energy Use
• Identify Opportunities for Energy Savings
• Provides a Baseline for Measuring
Improvements in Performance
• Trending Energy Performance Over Time
Reveals Operating Alternatives
• Uncovering Best Practices for Superior Energy
Performance – Equipment and Technology
Comparisons
Energy Measurements
• Electrical - Demand and consumption.
– Demand – kilowatts (kw) – think of as rated
connected horsepower – how much horsepower
for given speed, rate of flow?
– Consumption – kilowatt hours (kwh) – use of
connected horsepower over time – how fast will it
go and how long traveled at given speed?
• Energy benchmark – kwh/MG how many miles
per gallon at a given speed?
Energy Measurements - Kw & kwh
•
•
•
•
Lights – watts or watts/1000 = kw
Motors – horsepower x 0.746 = kw
Direct Heat/Hot Water = kw
Plug Ins – computers, printers, heaters – watts or
watts/1000 = kw
• Quality Control Instruments = watts
• Btus/hr x 0.000293 = kw x 1 hr = 1 kwh
• 1000 watts = 1 kw x 1 hr = 1 kwh
How Much Does It Cost?
Are you on the right rate schedule?
Example: Billing Information
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•
•
•
•
•
Given: 1.5 MGD WT/WWT Plant
Billing Demand – 250 kw, Contract Demand 350 kw
Consumption – 130,000 kwh/month, 3Ø, PF > 0.85
Re-Sale Power - Rate Schedule
Customer Charge - $ 50
Demand Charge - $17.15/kw x (250-50)kw = $3,430
Energy Charge – 15,000 kwh x 11.719¢/kwh + (130,000
– 15,000) x 6.696¢/kwh = $9,458.25
Month’s Electricity Cost - $12,938.25 + 2.83 % tax
Have you calculated your energy cost?
Demand Reduction Savings
• Most Significant Means
1. Operation Control and
2. Time of Use Contracting
Requires :
– Inventory of Large Motors
– Time of Use Operational Flexibility
– Knowledge of Utility Opportunity Windows
• Receive Double Dip Savings – Consumption
and Demand Savings
Time of Use (TOU) Contracting
• Electricity Cost Based Upon Reduced Rates for:
– Time of the Year
– Time of the Week
– Time of the Day
• Can Daily, Weekly, and Seasonal Operation be
Controlled by Process Flexibility with Varying
Throughputs? Storage Buffers Exist? Catch Up
Capacity Good? Knowledge Indicators in Place?
Windows of Opportunity - TOU
Demand Shifting Example
• 300 kw with 50 kw Shifted to TOU Window
Service
SGS Utility B
< 1000 Kw
SGS Utility B
TOU
Customer
Charge $
$21
$21
Demand
Kw $
Energy
Kwh $
130,000 kwh x
$4.89 x 300 kw $0.0703/kwh =
= $1,467
$9,139
$7.48/kw x 250
kw + 300 kw x
$1/kw = $2,170
Total
$/Month
$10,606
On Peak 42,900
kwh x $0.0606 +
Off Peak 87,100
kwh x $0.0485 =
$6,824
$9,034
Savings
$1,572/Mo
Effective Energy Management
• Conduct an Energy Survey
• Calculate the Demand and Consumption of the
Largest Motors
• 100 Hp Motor May Cost $50,000/yr To Run
Continuously
• Use Motor Master® if More Than 10 Large Motors
– Free program download - US Dept. of Energy
– http://www1.eere.energy.gov/manufacturing/tech_assistan
ce/software_motormaster.html
Motor Master® Software 4.01
Repair vs. Replace Decision Basis
Energy Benchmarking
• EPA Energy Star® Portfolio Manager Water/Wastewater Treatment Plants
• Rating System – 1 to 100
• http://www.energystar.gov/index.cfm?c=water.w
astewater_drinking_water
Energy Star® Benchmarking
• Compares energy intensity of a single facility with
similar facilities nationwide
• Kbtus/GPD = Total annual source energy/avg. GPD
• Input Data – Zip code, avg. influent and effluent flow,
avg. influent and effluent BOD5 facility design flow,
Processes Present – Nutrient removal, trickle
filtration, etc.
• Performance = Actual source energy use
intensity(EUI)/energy intensity predicted by Energy
Star Model Number 1 to 100
Pump Size vs. Efficiency
• Impeller Sized for Best Efficiency
Point (BEP) Head & GPM?
• Are You in the Zone?
• Single 1,000 gpm Pump @ 400 ft.
Head Cost $66,000 Annually At
$0.07/kwh at 70% Pump Efficiency
and $61,600 at 75% Efficiency
Pumping – Best Efficiency Point (BEP)
BEP
Where You Operate Is Important!
Costly
Cost Of Throttling Design Capacity
• BEP design flow range @ 83% efficiency, 60 Bhp
– Min. flow – 1050 gpm @ 175’ head
– Max. flow – 1250 gpm @ 160’ head
• Throttle capacity back to 600 gpm, what does it cost?
• Bhp = 600 gpm x 190’/3960 x 0.70 eff. = 41 x 0.746
kw/bhp = 30.6 kw x 8760 hrs/yr = 267,833 kwh x
$0.07/kwh = $18,775
• Pump design has 60 Bhp motor that costs $27,446/yr
to operate but needs only 40 Bhp motor so throttling
is costing $27,446 - $18,775 = $8,692/yr about $1/hr
Energy Use By Water Treatment Process
10 MGD - Per Cent Energy Use
0.2
2.1
11.1
Raw Water Pumping
0.4
4.7 1.4
Coagulation Feed
0.3
3
8.6
Polymer Feed
Rapid Mixing
0.3
Floculation
Sedmentation
Gravity Filtration
67
0.4
Surface Wash
In Plant Pumping
Hypo Feed
Fin. Water Pumping
Admin, Lab, Maint.
Cherokee Water Treatment Plant
Intake Pump House Upgrade
Existing
• 2 – 130 HP premium efficiency
• Certified Pump curve
operating Point 80% efficiency
@ 2100 gpm @160 ft head
• Operating one pump at a time
• Average Actual Pumping 972
GPM
• Flow controlled by throttling
the discharge of the pump
Proposed Upgrade
• Retrofit the two pumps with
MagnaDrive - adjustable
speed control
• Cost Savings $33,000 annual
($0.072/kWh)
• Installed cost $30,000 for
both motors (under
construction)
• Considering broader
solutions ($800k)
Town of Valdese WWTP
Influent Pump Upgrades, 2011
Existing
• Designed for 7.5 MGD
• Operating Average 2.0 MGD
• 2- 200 HP pumps w/1st
generation variable
frequency drives (VFD)
• Energy use: 300,906 kWh/yr
• Energy demand:132 kW
peak
• Significant maintenance
issues due to oversize
Upgrade
• 2 – 75 HP with VFD
• Energy Use: 213,113 kWh/yr
• Energy Demand: 50.2 kW
peak
Savings:
• Greatly reduced maintenance
issues and costs
• 87,793 kWh/year
• $7,900/year
• Project Cost: $120,000
Town of Mars Hill
Plant Facility Upgrades W&WWTP
Description: Upgrades 2012
• Lighting: T-8 upgrade
• HVAC Mini split systems
replace with single Heat Pump
• Electric to Gas fired IR Heaters
• Overhead door: R8 Insulation
with seals
• Hot water system 80 gal to 40
• 1,500 sf WWTP
• 2,780 sf WTP – lab and tank
room
Energy Savings
• 5350 kWh/year WTP
• 51 MMBTU Propane
• 601 kWh hot water
• 7.5 MMBTU – WWTP
• All energy savings projects
were bundled together and
scoped at 3.5 year payback
Other Energy Savings Opportunities
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•
•
•
•
•
•
Lighting – T12’s to T8’s, LED Yard Lighting
IR Heating vs. Unit Propane Heaters
Heat Pumps – SEER > 14
Solar – Hot Water
Programmable Thermostats
Occupancy Sensors
Central Controls
Recap -Energy Savings Result From:
• Understanding Process Potential – Energy
Assessment of Operations and Equipment
• Comparing to Best Practices – Benchmarking
• Life Cycle Analysis of Cost with Efficiency Gains
• Establishing Best Operating Points
• Evaluating Utility Rate Schedule Options with
Demands and Consumption Processes
• Tracking Energy Use and Comparing to Target
Performance Criteria
Know your state resources
WASTE REDUCTION PARTNERS
• Providers of Water, Energy, and Solid Waste Assessments
• Evaluations and Audits for Industrial, Commercial and
Institutional Customers
• Generally no cost, confidential, and non-regulatory
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•
•
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Technical Assistance
Contracted Services
Statewide Staffing
www.wastereductionpartners.org
Partnership Program with NC Div. of Environmental
Assistance and Outreach
Commercial / Industrial Water Assessments
• Waste Reduction Partners (WRP) conducts CII water audits in the state of
North Carolina
• Auditors go on site to use customer information to generate historical
performance patterns and recommend practical efficiency solutions
• Retired team of volunteer Engineers, Scientists and Executives keeps
costs low, experience high
• WRP can work with Water Utilities or end customers
• Report supplied to customer and utility outlines water use history,
effective recommendations, and financial pay back
Annual Results Comparing Two
Demand-Side Strategies
Strategy Type
Utility Cost
Annual Gallons
Saved
Cost Per
CCF Saved
High Efficiency Toilet Rebate @
$30
$15,000
4,315,662
$2.60 / CCF
Waste Reduction Partners I.C.I.
Audit Program
$15,000
7,480,500
$1.50 / CCF
Identifying Opportunities:
Basics of Conducting an Energy Audit
• Scope
• Energy/utility bill review – Before site visit
•
•
•
Plot the usage data – does it make sense?
Check rate schedule – other “add ons”
Benchmarking
• Have the right people on the team
• Data collection – on site
• Target Energy Uses
•
Process/motors, HVAC, lighting
• Getting the questions answered
• Recommendations
• Financial analysis – cost, savings, payback
USI Checklist
Site:
Building: (Name,
year built)
Site Contact -Title
Name:
Phone:
E-mail:
County:
Use (Office, etc.)
Floor Area: (GSF)
Street Address:
Mailing Address:
City:
State:
Zip Code:
Surveyor Name:
Team:
Survey Date:
Survey Time:
Administration and Energy Conservation Measures (ECM) Survey
# of floors
# of occupants
Hrs. occupied per week
Utilities supplied to bldg. (Enter 1 if
present, 2 if present and metered):
Electric
Dom cold water
Natural gas
Oil
Propane
Steam
Heating hot water
Chilled water
Dom hot water
Client - Please complete the top
of this page and pages 2 and 3
The section below is completed by WRP assessor.
Baseline Energy Data (See Annual Energy Consumption Worksheet):
Total energy consumed:
0 Million BTUs of energy per year
Total energy index:
#DIV/0!
kBTU/sq. ft. per year
Total energy costs:
$0.00 Per year
Total energy cost index:
#DIV/0!
Total Energy Cost
Total water use:
0 Gallons per year
Water/sewer cost:
$0.00 Per year
Gallons per Occupant:
#DIV/0!
Gallons / sf
#DIV/0!
After-hours usage/year After-hours usage/year -
ANNUAL ENERGY AND WATER CONSUMPTION
Month
Year
July
August
September
October
November
December
January
February
March
April
May
June
12-month total
Electricity
Usage
Cost
KWH
$
Other Fuels
Water
Cost
$
Usage
Units
H2O / Sewer
Cost
$
Usage
Gallons
2008
2008
2008
2008
2008
2008
2009
2009
2009
2009
2009
2009
0
0
0
$0.00
0
CONVERSION TO BTU EQUIVALENTS
Square footage:
Fuel totals
Electricity -kWh
Fuel oil - gallons
Natural gas - Therms
Propane -
Natural Gas
Cost
Therms
$
Usage
0
0
0
0
x
x
x
x
3,413 BTU/kWh
140,000 BTU/GAL.
100,000 BTU/THERM
92,000 BTU/GAL.
0
0
0
0
0
Total energy use
Cost per million BTU
Total Energy Index
Total Cost Index
0
#DIV/0!
#DIV/0!
#DIV/0!
Million BTU's
Million BTU's
Million BTU's
Million BTU's
Million BTU's
Million BTU's
kBTU/SF
Per Sq. Ft.
0
Average Electricity Usage and Demand
2,500
200
2,232
180
2,119
178
177
172
1,955
2,000
162
2,036
174
180
1,960
165
160
1,774
137
1,475
124
1,476
126
134
1,426
126
1,401
kWh/Day
1,500
140
1,644
120
100
1,000
80
60
500
40
20
0
0
Jul-11 Aug-11 Sep-11 Oct-11 Nov-11 Dec-11 Jan-12 Feb-12 Mar-12 Apr-12 May-12 Jun-12
kWh/Day
KW Demand
Actual KW
1,705
B. Building Envelope
Roof type
(check one)
Roof color
(check one)
B1.
B2.
B3.
B4.
B5.
B6.
B7.
Metal
Composite
Light
Dark
Membrane
Other
Is roof insulated?
Are thermal windows used? Low-e?
Are overhangs present on east west facing windows?
Is weather stripping on windows and doors present and maintained?
Are interior shades present and adjusted to allow daylight and reject solar heat gain?
Are windows kept closed in conditioned spaces?
C. Lighting and Electrical Systems
C1.
C2.
C3.
C4.
C5.
C6.
C7.
C8.
C9.
C10.
C11.
C12.
C13.
Can lighting be controlled in perimeter rooms to make use of day light?
Have T-12 fluorescent lamps been replaced with T-8?
Are occupancy sensors utilized?
Are computers using power-save feature?
Have all incandescent lamps been replaced by CFL's?
Are all electric exit lights of LED type?
Do exterior lights turn off during daylight hours?
Have space heaters been eliminated?
Have beverage and snack machine lights been removed?
Are procedures in place to purchase the most energy efficient equipment?
Is fluorescent task lighting used to minimize background lighting?
Has High-Bay T-5 lighting been evaluated for use in high ceiling areas (warehouses, gyms, auditoriums, etc.)?
Ha ve energy cons erva tion deca l s been pl a ced on l i ght s wi tches ?
K. Recommendations
List top ECM recommendations (include estimated potential savings when possible). Indicate if building is a candidate for
performance contracting.
K1.
1
Annual potential savings:
Cost to implement:
Simple payback:
2
Annual potential savings:
Cost to implement:
Simple payback:
3
Annual potential savings:
Cost to implement:
Simple payback:
4
Annual potential savings:
Cost to implement:
Simple payback:
Detailed Assessment Report – Example Summary
Recommendation
Cost Savings
Investment Cost
Payback Period
Set back, Set Forward Temperature Controls
$5,257
$3,000
6.8 months
Variable Speed Air Handler Fan Drives
$1,721
$3,175
1.8 years
$9/lamp/yr
0
Immediate
Motion Sensors
$396
$1,231
3.1 years
Metal Halide Lamps
$2,645
$1,922
8.7 months
LED Exit Lights
$176
$70
4.7 months
T-12 Light Replacement
$192
$700
3.6 Years
$3,825
0
Immediate
$14,212
$10,098
9.2 months
HVAC/Building Envelope
Lighting
Reduced Lighting Levels
Computers
Sleep/Hibernate Controls
Totals
Detailed Assessment Report - Examples
Savings – Switching of hallway lights
Estimated hours lights could be switched off: Weekends hrs = 10 hrs/day X 2
days X 52 weeks = 1,040 hrs. Schools out hours = 10 hrs/day X 5 days X 10
weeks = 500 hrs. Total hours = 1,040 + 500 = 1,540 hrs.
Cost Savings = 3 hallways X 23 fixtures X 75% switched off X .112 kwd/fixture
X 1,540 hrs/year = 8,926 kWh X $.084 kWh = $750 Yr.
Costs
Costs = TBD. A very rough estimate is $400 per hallway, or $800.
Payback Period = $800/$750 = 13 months
Estimated Annual Energy Savings, $/yr
Energy, Water & SW Savings
Energy Savings
MMBTU / year
kWh/yr
$4,459
119.96
32,500
Est. Annual Emissions Reductions, lbs/yr
Carbon Dioxide (CO2)
1.19#CO2/kWh * 32,500kWh/yr =
Nitrogen Oxides ()
0.00293#/kWh * 32,500kWh/yr =
Sulfur Oxides (SOX)
0.00761#SOX * 32,500kWh/yr =
38,675
95
247
Summary of Energy Benchmarks
Total Energy Consumed
Total Energy Index
Total Energy Cost:
Total Energy Cost Index:
1,597 Million Btu / yr
51.5 kBtu / sq ft / yr
$33,615 / yr
$1.08 / sq ft / yr
WRP Contacts
WRP - Land-of-Sky Regional Council
339 New Leicester Hwy, Suite 140
Asheville, NC 28806
828-251-6622 wrp@landofsky.org
Russ Jordan, WRP Energy Manager
Terry Albrecht, WRP State Director
WRP - Triangle J Council of Governments
PO Box 12276
Research Triangle Park, NC 27703
919-558-2702 wrp@tjcog.org
Conrad Meyer, Technical Manager
Christal Perkins, Program Administrator
www. wastereductionpartners.org
Backup Slides
Savings Opportunities
• Large Motor Efficiency – 85% to 95%
• Centrifugal Pumps – Operating Points
• Capacity Control – Throttling vs. Variable
Frequency Drives
• Treatment Optimization – Aeration, DO
• Recirculation / Processing Volume Reduction
• Demand Control
Motors Cost of Operation
• The Energy Policy Act (EPACT) of 1992 mandates that motors
up to 200 hp, 3Ø, General Purpose service manufactured after
Oct. 24, 1997 must meet minimum efficiency levels.
• Cost to Operate at $0.07/kwh and 8760 hrs/yr
Motor
50 hp
Efficiency
Pre
$24,497
EPACT
75 hp
100 hp
200 hp
$36,266
$48,244
$95,565
EPACT
$23,891
$35,418
$47,224
$93,553
NEMA
PREM.
$23,512
$35,082
$46,480
$92,772
Getting to the Pump’s
Best Efficiency Point
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•
•
•
•
Impeller Trimming
Control Valve Throttling
Jockey Pumping
Variable Speed Drive – Steep Pump Curve Only
Pump Software for Analysis
http://www1.eere.energy.gov/industry/bestpractices/software_psat.html
• Does Operation Require Catch-up and Slow-down
Capacity? How Often?
• Yes – VFD on Smaller Pump
• No – Impeller Trimming to Meet BEP