1© 2010 Electric Power Research Institute, Inc. All rights reserved.
Virtual Power PlantModeling & Simulation
Gale HorstProject Manager, Smart Grid Demonstrations
Electric Power Research Institute (EPRI)
Roger DuganSr. Technical Executive
Electric Power Research Institute (EPRI)
2© 2010 Electric Power Research Institute, Inc. All rights reserved.
American Electric Power (AEP) Virtual Power Plant Simulator (VPPS)
3© 2010 Electric Power Research Institute, Inc. All rights reserved.
The Evolution of the Electric Utility SystemThe Evolution of the Electric Utility System
Before Smart Grid:One-way power flow, simple interactions
After Smart Grid:Two-way power flow, multi-stakeholder interactions
Adapted from EPRI Presentation by Joe HughesNIST Standards Workshop
April 28, 2008
4© 2010 Electric Power Research Institute, Inc. All rights reserved.
Smart Grid Enables Energy StorageSmart Grid Enables Energy Storage
Adapted from EPRI Presentation by Joe HughesNIST Standards Workshop
April 28, 2008
But where is the best location/size for the storage ?
5© 2010 Electric Power Research Institute, Inc. All rights reserved.
Migratory Path of Energy Storage Migratory Path of Energy Storage –– AEPAEP
Large Central Units
Storage at Grid Edge
Substation Batteries
Graphics adapted from an EPRI Presentation by Joe Hughes
6© 2010 Electric Power Research Institute, Inc. All rights reserved.
CES(Community)
Devaluators:• Aesthetics
Locational Value of Electricity StorageLocational Value of Electricity Storage
120 V240 V69 kV 4 to 34 kV 480 V138 kV345 kV765 kV
Storage Value
Central Units Distributed Units
Devaluators:• No Backup• High Security Risk• Less effect on losses
Pumped Hydro(Central)
Devaluators:• Safety Concerns• No Load Diversity• No Cost Sharing• Little Grid Benefits •No Standardization
ResidentialNaS
(Substation)
Devaluators:• Complex Islanding• Storage Size & Location•Medium Security Risk
7© 2010 Electric Power Research Institute, Inc. All rights reserved.
To Optimize StorageTo Optimize Storage
1.Very Close to Customers• Backup Power, • Buffer Customer Renewables
2.Grid-Connected• Load Leveling, • Volt / VAR support
3.Utility-Operated• Load Diversity (multiple customers on one storage)• Improved Safety• Optimizing Grid Performance
4.Utility-Owned• Standardization & Commodity Pricing• Socializing the Cost
Need an energy storage system with the following FOUR key features:
8© 2010 Electric Power Research Institute, Inc. All rights reserved.
CES CES –– A Virtual Substation BatteryA Virtual Substation Battery
Local Benefits:1) Backup power2) Voltage correction3) Renewable Integration
Substation
Power LinesCommunication and Control Links
CES
CES is Operated as a Fleet offering a Multi-MW, Multi-hour Storage
9© 2010 Electric Power Research Institute, Inc. All rights reserved.
CES CES –– A Virtual Substation BatteryA Virtual Substation Battery
Communication & Control Layout for
CES
Utility Dispatch Center /SCADACES Control Hub
Substation
Power LinesCommunication and Control Links
Integration Platform
CES CESCESCES
CES is Operated as a Fleet offering a Multi-MW, Multi-hour Storage
Grid Benefits:4) Load Leveling at substation5) Power Factor Correction6) Ancillary services
Local Benefits:1) Backup power2) Voltage correction3) Renewable Integration
10© 2010 Electric Power Research Institute, Inc. All rights reserved.
Benefits of Local Energy Benefits of Local Energy StoraeStorae
• More reliable Backup Power to customers (closer)
• More scalable, flexible implementation (many small units)
• More efficient in buffering customer renewable sources
• More synergy with Electric Vehicle batteries
• Easier installation and maintenance (240 V)
• A Unit outage is less critical to the grid (smaller)
While Local Storage can function as a Multi-MW, Multi-hour Substation Battery, It has Inherent Advantages over Larger Batteries located in Substations:
11© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Following Peak Shaving
Circuit Demand
12© 2010 Electric Power Research Institute, Inc. All rights reserved.
Community Energy Storage Simulations
In the
AEP Smart Grid Demonstration
Roger DuganSr. Technical Executive
Electric Power Research Institute (EPRI)
13© 2010 Electric Power Research Institute, Inc. All rights reserved.
Circuit Diagram
84 Storage Elements25 kW each
14© 2010 Electric Power Research Institute, Inc. All rights reserved.
Voltage Profile
Voltage Profile Plot
0.97
0.98
0.99
1
1.01
1.02
1.03
1.04
1.05
0 0.5 1 1.5 2 2.5 3 3.5 4
Distance from Substation
Per
Uni
t Vol
tage
V1V2V3
15© 2010 Electric Power Research Institute, Inc. All rights reserved.
Storage Element Model in OpenDSS
% Eff. Charge/DischargeIdle | Discharge | Charge
Idling Losses
kW, kvar
kWh STORED
Other Key Properties
% ReservekWhRatedkWhStored%StoredkWRated
etc.
16© 2010 Electric Power Research Institute, Inc. All rights reserved.
StorageController Element in OpenDSS
Discharge ModeCharge Mode
kW TargetDischarge Time
Total Fleet kW CapacityTotal Fleet kWh
et. al.
Storage “Fleet”Substation
V, IComm Link
Time + Discharge ratePeak ShavingLoad FollowingLoadshape
17© 2010 Electric Power Research Institute, Inc. All rights reserved.
Example Simulations
Investigating 25, 50, and 75 kWh storage options with various
discharging schemes
18© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Peak Shave, Target=8000 kW, Storage=75 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
10
20
30
40
50
60
70
80
Base kWNet kW kWh Stored
19© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Peak Shave, Target=8000 kW, Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
20© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Peak Shave, Target=8000 kW, Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
“Ran Out of Gas”
21© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Load Follow, Time=12:00, Storage=75 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
10
20
30
40
50
60
70
80
Base kWNet kW kWh Stored
22© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Load Follow, Time=12:00, Storage=75 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
10
20
30
40
50
60
70
80
Base kWNet kW kWh Stored
12:00 is too early Load declines after 12:00
23© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Load Follow, Time=12:00, Storage=50 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
10
20
30
40
50
60
Base kWNet kW kWh Stored
24© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Load Follow, Time=12:00, Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
25© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Load Follow, Time=13:00, Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
26© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Load Follow, Time=14:00, Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
27© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Time + fixed rate, Time=12:00 @ 30%, Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
28© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Time + fixed rate, Time=12:00 @ 30%, Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
Quickly discharges to reserve kWh
29© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Time + fixed rate, Time=14:00 @ 25% Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 50 100 150 200 250 300
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
30© 2010 Electric Power Research Institute, Inc. All rights reserved.
Load Shapes With and Without StorageMode=Time + fixed rate, Time=14:00 @ 25% Storage=25 kWh
Charge=2:00 @ 30%
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
200 210 220 230 240 250
Hours
kW
0
5
10
15
20
25
30
Base kWNet kW kWh Stored
(Expanded Scale)
31© 2010 Electric Power Research Institute, Inc. All rights reserved.
Conclusions
• 25 kWh storage is quickly depleted when used for day‐to‐day peak shaving– Have to be very careful with discharge strategy
• Load following with a later time trigger is likely more useful than a fixed discharge rate or an early time trigger
• 75 kWh would be “nice to have”– Costs are a factor
32© 2010 Electric Power Research Institute, Inc. All rights reserved.
Discharge Algorithm Development
Scheduled Discharge
0
1000
2000
3000
4000
5000
6000
7000
8000
Load
(kW
)
Load without Battery
Load with Battery
Aug 3rd Aug 4th Aug 5th Aug 6th Aug 7th
Is it time to trigger ?
33© 2010 Electric Power Research Institute, Inc. All rights reserved.
Discharge Algorithm Development
Scheduled Discharge
0
1000
2000
3000
4000
5000
6000
7000
8000
Load
(kW
)
Load without Battery
Load with Battery
Aug 3rd Aug 4th Aug 5th Aug 6th Aug 7th
Is it time to trigger ?
34© 2010 Electric Power Research Institute, Inc. All rights reserved.
Discharge Algorithm Development
Scheduled Discharge
0
1000
2000
3000
4000
5000
6000
7000
8000
Load
(kW
)
Load without Battery
Load with Battery
Aug 3rd Aug 4th Aug 5th Aug 6th Aug 7th
Is it time to trigger ?
35© 2010 Electric Power Research Institute, Inc. All rights reserved.
Discharge Algorithm Development
Scheduled Discharge
0
1000
2000
3000
4000
5000
6000
7000
8000
Load
(kW
)
Load without Battery
Load with Battery
Aug 3rd Aug 4th Aug 5th Aug 6th Aug 7th
Is it time to trigger ?
36© 2010 Electric Power Research Institute, Inc. All rights reserved.
Discharge Algorithm Development
Scheduled Discharge
0
1000
2000
3000
4000
5000
6000
7000
8000
Load
(kW
)
Load without Battery
Load with Battery
Aug 3rd Aug 4th Aug 5th Aug 6th Aug 7th
37© 2010 Electric Power Research Institute, Inc. All rights reserved.
AEP Approach to Smart Grid Technology Simulations
38© 2010 Electric Power Research Institute, Inc. All rights reserved.
Together…Shaping the Future of Electricity