DIMACS Workshop on Algorithmic Decision
Theory for the Smart Grid
Challenges of Generation from
Renewable Energy on
Transmission and Distribution
Operations
James T. Reilly
Consultant
October 25, 2010
Evolution of Smart Grid
• IntelliGrid Architecture
Integration of the power and energy delivery system
and the information system (communication,
networks, and intelligence equipment) that controls it.
• Demand Response / Smart Meters
Customers reduction or shift in use during peak periods
in response to price signals or other types of
incentives.
Smart meters with two way communications
• Integration of Renewable Energy
Renewable Portfolio Standards
IntelliGrid
(2000)
Electrical
Infrastructure
Intelligence
Infrastructure
Integrated Energy and Communications System Architecture – 2001
Rev 0 Architecture – 2004
IntelliGrid Vision
Power System of the Future
 A power system made up of numerous automated
transmission and distribution systems, all operating in a
coordinated, efficient and reliable manner.
 A power system that handles emergency conditions with
‘self-healing’ actions and is responsive to energy-market
and utility business-enterprise needs.
 A power system that serves millions of customers and
has an intelligent communications infrastructure enabling
the timely, secure and adaptable information flow
needed to provide reliable and economic power to the
evolving digital economy.
Smart Grid Domains
(2010)
Source: NIST Smart Grid Framework 1.0,
September 2009
Direction of Smart Grid
To date, the smart grid in the United States
has been dominated by smart metering
and as an enabler for demand
management.
Now, the direction is turning towards being
an enabler for the integration of
renewables into distribution networks and
the bulk power system.
US Electric Power Industry
Net Generation (2008)
Sources: U.S. Energy Information Administration, Form EIA-923, "Power Plant Operations Report.”
Renewable Portfolio Standards
WA: 15% x 2020*
MN: 25% x 2025
MT: 15% x 2015
(Xcel: 30% x 2020)
(large utilities)*
5% - 10% x 2025 (smaller utilities)
IA: 105 MW
CO: 30% by 2020
UT: 20% by 2025*
MA: 22.1% x 2020
KS: 20% x 2020
New RE: 15% x 2020
(+1% annually thereafter)
RI: 16% x 2020
NY: 29% x 2015
CT: 23% x 2020
OH: 25% x 2025†
(IOUs)
10% by 2020 (co-ops & large munis)*
CA: 33% x 2020
NH: 23.8% x 2025
x 2015*
SD: 10% x 2015 WI: Varies by utility;
10% x 2015 statewide
NV: 25% x 2025*
New RE: 10% x 2017
MI: 10% + 1,100 MW
ND: 10% x 2015
OR: 25% x 2025
ME: 30% x 2000
VT: (1) RE meets any increase
in retail sales x 2012;
(2) 20% RE & CHP x 2017
IL: 25% x 2025
PA: ~18% x 2021†
WV: 25% x 2025*†
NJ: 22.5% x 2021
VA: 15% x 2025*
MD: 20% x 2022
MO: 15% x 2021
AZ: 15% x 2025
DE: 20% x 2020*
NC: 12.5% x 2021
(IOUs)
10% x 2018 (co-ops & munis)
NM: 20% x 2020 (IOUs)
DC
DC: 20% x 2020
10% x 2020 (co-ops)
TX: 5,880 MW x 2015
HI: 40% x 2030
State renewable portfolio standard
Minimum solar or customer-sited requirement
State renewable portfolio goal
Extra credit for solar or customer-sited renewables
Solar water heating eligible
*†
Includes non-renewable alternative resources
Source: Interstate Renewable Energy Council (June 2010)
29 states +
DC have an RPS
(6 states have goals)
8
Variable Generation Impact on Bulk Power System
Dispatch – No Renewables
Study Area Dispatch – Week of April 10th – No Renewables
Variable Generation Impact on Bulk Power System
Dispatch – 10% Renewables
Study Area Dispatch – Week of April 10th – 10% R
Variable Generation Impact on Bulk Power System
Dispatch – 20% Renewables
Study Area Dispatch – Week of April 10th – 20% R
Variable Generation Impact on Bulk Power System
Dispatch – 30% Renewables
Study Area Dispatch – Week of April 10th – 30% R
Tehachapi Wind Generation
April 2005
Could you predict the energy production for this wind park,
either day-ahead or 5 hours in advance?
700
Each Day is a different color.
600
Day 29
Megawatts
500
Day 9
400
Day 5
Day 26
300
Average
200
100
0
1
-100
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour
Source: CAISO
Variable Generation Impact on Bulk
Power System

Output can be counter to load ramps
or faster than system ramp

Unpredictable patterns – wind
variability and large imbalances, esp.
during disturbances and restoration
efforts


9700
9200
8700
Low capacity factor – can be zero at
times of peak
8200
Voltage issues – low voltage ride
through (LVRT)
7200
0:00

Reactive & real power control issues

Frequency & Inertial Response issues

Oversupply conditions
350
300
250
200
7700
6:00
12:00
Load
18:00
Wind
150
100
50
0
-50
0:00
Operational Issues
The operational issues created by variable generation result from the
uncertainty created by the variable output and the characteristics of
the generators themselves, such as the inertial response and
dynamic response during fault conditions. The impacts are also
affected by factors specific to the particular variable generation site,
its interconnection to the power system, the characteristics of the
conventional generators within the system being operated, and the
rules and tools used by the particular system operator.
The operational issues created by variable generation can be
considered in terms of various time frames: seconds to minutes,
minutes to hours, hours to day, day to week, and week to year and
beyond.
Source:
Integration of Variable Generation into the Bulk Power System, NERC. July 2008.
Operational Issues – Time Scale
Source: John Adams, GE
Operational Practices to
Accommodate Variable Generation










Substantially increase balancing area cooperation or consolidation, either real or
virtual
Increase the use of sub-hourly scheduling for generation and interchanges
Increase utilization of existing transmission
Enable coordinated commitment and economic dispatch of generation over wider
regions
Incorporate state of the art wind and solar forecasts in unit commitment and grid
operations
Increase the flexibility of dispatchable generation where appropriate (e.g., reduce
minimum generation levels, increase ramp rates, reduce start/stop costs or minimum
down time)
Commit additional operating reserves as appropriate
Build transmission as appropriate to accommodate renewable energy expansion
Target new or existing demand response or load participation programs to
accommodate increased variability and uncertainty
Require wind plants to provide down reserves
Source: Western Wind and solar integration study, May 2010 Prepared for NREL by GE Energy. May 2010.
The technical analysis performed in this study shows that it is operationally feasible for WestConnect to
accommodate 30% wind and 5% solar energy penetration, assuming these changes to current practice are made
over time.
DER Interconnection
Distributed Energy
Technologies
Interconnection
Technologies
Functions
Fuel Cell
• Power Conversion
PV
Electric Power
Systems
Utility
System
• Power Conditioning
Inverter
Micro turbine
• Power Quality
• Protection
Wind
• DER and Load
Control
Energy
Storage
PHEV;
V2G
Generator
• Ancillary Services
Switchgear,
Relays, &
Controls
• Communications
• Metering
Micro grids
Loads
Local
Loads
Load Simulators
Technologies to Accommodate
Renewable Generator Behaviors
 Energy Storage & Intelligent Agent (temporal power flow
control)
 Solar and Wind Forecasting Tools
 Power Flow Control (spatial)
 Demand Response
 Distributed Generation
 Generator and Load Modeling
 Statistical and Probabilistic Forecasting Tools
 Advanced Intelligent Protection Systems
 Synchrophasor Monitoring
Smart Grid
Reliability
System Restoration
Reilly Associates
PO Box 838
Red Bank, NJ 07701
Telephone: (732) 706-9460
Email: j_reilly@verizon.net