Integrating Traditional, Variable, Renewable, Distributed, and Demand-Side Response Resources G RID...
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Transcript of Integrating Traditional, Variable, Renewable, Distributed, and Demand-Side Response Resources G RID...
Integrating Traditional, Variable, Renewable, Distributed, and Demand-Side Response Resources
GRIDSCHOOL 2010MARCH 8-12, 2010 RICHMOND, VIRGINIA
INSTITUTE OF PUBLIC UTILITIESARGONNE NATIONAL LABORATORY
Thomas D. VeselkaCenter for Energy, Economic, and Environmental Systems Analysis
Decision and Information Sciences DivisionARGONNE NATIONAL LABORATORY
[email protected] 630.252.6711
Do not cite or distribute without permission
MICHIGAN STATE UNIVERSITY
Veselka - 02
GridSchool 2010
The Grand Challenge of Integrating Renewable Resources with Variable and Intermittent Production into the Grid Is the Ability to Respond to Rapid and Unpredictable Fluctuations
0
5
10
15
20
25
30
35
40
4515
16
17
18
19
20
21
Day of the Month in August
Win
d O
utp
ut
(MW
)
Total of 3 Sites
Wind is not Always Available when Needed Most
Rapid Ramping
The thermal system or loads need to adjust quickly
Veselka - 03
GridSchool 2010
Wind Probability Profiles Vary Seasonally and by Time of Day
0
10
20
30
40
50
60
70
80
90
0 25 50 75 100Exceedance Probability (%)
Gene
ratio
n (M
Wh)
February - 4 AMFebruary - 6 PMAugust - 4 AMAugust - 6 PMAll Hours of Year
Exceedance Probability (%)
Win
d P
rod
uct
ion
(M
W)
Summer Nighttime Wind Is Less than Daytime Wind
Winter Wind Is Greater Than Summer Wind
On Average, Wind Output Decreases in the Morning When Load Is Rapidly Increasing.The Opposite Occurs in the Evening.
Veselka - 04
GridSchool 2010
Wind Resources Vary Widely Across the United StatesOften the Best Wind Resources Are Far from Major Load Centers
TransmissionTransmission
MISO
PJM765 kV
Veselka - 05
GridSchool 2010
The U.S. has Installed the Most Wind Capacity in the World, but the Percent Penetration Rate (% Production) Is Relatively SmallU.S. recently became the world leader in wind power with over 8 GW installed in 2008 and 25 GW total installed capacity (AWEA, Feb 09)
Veselka - 08
GridSchool 2010
Does Wind Power Influence Market Operations?
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
-120.0
-70.0
-20.0
30.0
80.0
130.0
180.0
1 25 49 73 97 121 145
Win
d Po
wer
[MW
]
Pric
e [$
/MW
h]
Time [hour]Day Ahead price Real Time price Wind power
Negative prices (LMPs)
Wind power ramping events
Midwest ISO Wind Power and MN Hub Prices, May 11-17, 2009:http://www.midwestiso.org/
Veselka - 010
GridSchool 2010
There Are Several Different Types of Photovoltaic Technologies, Each of Which Has its Own Set of Attributes
One Size Does Not Fit All
Luminescent Solar Concentrators withMultijunctionCells (~40%)
Veselka - 011
GridSchool 2010
Photovoltaic Efficiencies Have Increased Dramatically Since the Mid-1970’s and Are Expected to Continue Improve
Source: http://en.wikipedia.org/wiki/Solar_cell
Veselka - 012
GridSchool 2010
Public Service Company of Colorado Solar Study200 MW of PV & 200 MW CSP with 800 MWh Storage
Source: http://www.xcelenergy.com/SiteCollectionDocuments/docs/PSCo_SolarIntegration_020909.pdf
Veselka - 013
GridSchool 2010
Spanish PV Study: Annual Hourly Photovoltaic OutputG
ener
atio
n (k
W)
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Source: http://www.icrepq.com/ICREPQ'09/abstracts/520-ramon-abstract.pdf
Veselka - 014
GridSchool 2010
Most States Have a Renewable Portfolio Standard (RPS)
Source: www.dsireusa.org / September 2009
State renewable portfolio standard
State renewable portfolio goal
Solar water heating eligible *† Extra credit for solar or customer-sited renewables
Includes separate tier of non-renewable alternative resources
WA: 15% by 2020*
CA: 20% by 2010
☼ NV: 25% by 2025*
☼ AZ: 15% by 2025
☼ NM: 20% by 2020 (IOUs)
10% by 2020 (co-ops)
HI: 40% by 2030
☼ Minimum solar or customer-sited requirement
TX: 5,880 MW by 2015
UT: 20% by 2025*
☼ CO: 20% by 2020 (IOUs)
10% by 2020 (co-ops & large munis)*
MT: 15% by 2015
ND: 10% by 2015
SD: 10% by 2015
IA: 105 MW
MN: 25% by 2025
(Xcel: 30% by 2020)
☼ MO: 15% by 2021
WI: Varies by utility;
10% by 2015 goal
MI: 10% + 1,100 MW by 2015*
☼ OH: 25% by 2025†
ME: 30% by 2000New RE: 10% by 2017
☼ NH: 23.8% by 2025☼ MA: 15% by
2020+ 1% annual
increase(Class I Renewables)RI: 16% by 2020
CT: 23% by 2020
☼ NY: 24% by 2013
☼ NJ: 22.5% by 2021
☼ PA: 18% by 2020†
☼ MD: 20% by 2022☼ DE: 20% by 2019*☼ DC: 20% by 2020
VA: 15% by 2025*
☼ NC: 12.5% by 2021 (IOUs)
10% by 2018 (co-ops & munis)
VT: (1) RE meets any increase in retail sales by
2012; (2) 20% RE & CHP by 2017
29 states & DC
have an RPS5 states have goals
KS: 20% by 2020
☼ OR: 25% by 2025 (large utilities)*
5% - 10% by 2025 (smaller utilities)
☼ IL: 25% by 2025
Standards Should be Consistent with Renewable Resources & Needs
Veselka - 015
GridSchool 2010
Currently, Volatility in Production from Variable Resources Are Accommodated by Changing Thermal Unit and Hydroelectric Power Plant Production Levels
Time
Ou
tpu
t (M
W)
OperatingCapacity
Ram
p U
p R
ate
Ram
p D
ow
n R
ateMinOutput
Cold Start Time
MinimumDownTime
MinimumUp
Time
Lo
ad F
ollo
win
g
Ran
ge
The Greater the Operational Flexibility of Dispatchable Units, the more Variability the Grid Will Accommodate
Veselka - 016
GridSchool 2010
Some Technologies Are Able to Come On-line Quickly to Respond to Rapid Load Changes while Others Respond More Slowly
0 2 4 6 8 10 12 14 16 18 20
Fossil Steam
Hydroelectric
Combined Cycle
Gas Turbine
Diesel Generator
Nuclear Steam
Ramp Rates (%/min)
0 5 10 15 20 25
Fossil Steam
Hydroelectric
Combined Cycle
Gas Turbine
Diesel Generator
Nuclear Steam
Cold Start Time (Hours)
Weeks for Shutdown and Startup
Some Hydropower Plants Change Very Quickly
Veselka - 017
GridSchool 2010
The Load Following Range Is Restricted by the Output Minimum and Generation Capacity
0 10 20 30 40 50 60 70 80 90 100
Fossil Steam
Hydroelectric
Combined Cycle
Gas Turbine
Diesel Generator
Nuclear Steam
Minimum Output (% of Capacity)
Time
Pro
du
ctio
n (
MW
)
Operating Capacity
Ram
p U
p
Rat
e
Ram
p D
ow
n
Rate
Cold Start Time
MinimumDownTime
MinimumOutput
Lo
ad F
ollo
win
g
Ran
ge
MinimumUp
Time
Veselka - 018
GridSchool 2010
GTHighest
ProductionCosts
NGCC
Cycling Coal
Base Load Coal
Ideally, Units Are Dispatched Based on Production Cost
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
Max Load
Min Load
NuclearLowestProductionCosts
Nuclear12 $/MWh
Coal25 $/MWh
NGCC41 $/MWh
Cycling Coal
32 $/MWh
Gas Turbines80 $/MWh
ResourceStack
Su
pp
ly (
MW
)
Veselka - 019
GridSchool 2010
0 10 20 30 40 50 60 70 80 90 100
Fossil Steam
Hydroelectric
Combined Cycle
Gas Turbine
Diesel Generator
Nuclear Steam
Minimum Output (% of Capacity)
Unfortunately, a Steam Plant (e.g., Cycling Coal) Does not Have the Flexibility to Operate at a Very Low Output Level
GTHighest Production
Costs
NGCC
Cycling Coal
Base Load Coal
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
Max Load
Min Load
NuclearLowestProduction Costs
Ram
p U
p
Ram
p Dow
n
GT Operations
Veselka - 020
GridSchool 2010
Wind Production Will Serve Some of the Load.This Production Reduces the Loads that Are Served by other Generating Resources
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad/W
ind
Ou
tpu
t (M
W)
Max Load
Min Load
WindGeneration
Ram
p U
p
Ram
p Dow
n
Veselka - 021
GridSchool 2010
Dispatchable Units Serve a Load Profile that Typically, but not Always, Has Greater Fluctuations Relative to the Case where there Is no Wind
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
New Max
New Min
Wind Typically Increases Resultant Load Changes
Larger Range of O
perations
Ram
p U
p
Ram
p Dow
n
Veselka - 022
GridSchool 2010
NGCC
GT
Cycling Coal
Nuclear
Base Load Coal
LowestO&M Costs
HighestO&M Costs
Unit Dispatch with Wind Results in Less Thermal Generation & Associated Air Emissions
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
Without Wind
With Wind
Coal May OperateLess Efficiently @ Min Gen
Veselka - 023
GridSchool 2010
0 100 200 300 400 500 600
Fossil Steam
Hydroelectric
Combined Cycle
Gas Turbine
Diesel Generator
Nuclear Steam
CO2 Emissions (kg CO2/BOE)
Wind and other Renewable Technologies Will Reduce Greenhouse Gas Emissions
20 Percent Wind by 2030 Report: CO2 Emissions Are Estimated at 25 Percent Lower Than a No-Wind Scenario
Veselka - 024
GridSchool 2010
As a Result of Variable Resource Generation Some Units Will Operate at a Different Efficiency Point
20
30
40
50
60
70
80
90
100
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Net
Elec
tric
al Effi
cien
cy (%
)
Fraction of Full Load
Combined Cycle
Hydro
Diesel
Nuclear
Fossil Steam
Veselka - 025
GridSchool 2010
NGCC
GT
Cycling Coal
Nuclear
Base Load Coal
LowestO&M Costs
HighestO&M Costs
Unit Dispatch with Greater Nighttime Wind Base Load Coal Unit May Need to Be Taken Off-line for Several Hours
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
Without Wind
With Wind
Sell
Veselka - 026
GridSchool 2010
Pump
Energy is Produced
When Generating
Energy is ConsumedWhen Pumping
Substation
Upper Reservoir
LowerReservoir
Pumped Storage Plants Can Be Used to Help Smooth Out Loads Served by Other Dispatchable Resources
Fill Load Valley (Consume) to Utilize Low Cost Production and Avoid Expensive Shutdown Costs
React to Sudden Changes in Variable Resource Production
Lo
ad (
MW
)
Hour of the Day
Veselka - 027
GridSchool 2010
When a Unit Is Forced Out of Service, the System Responds by Altering the Dispatch
Nuclear8 $/MWh
Base Coal
25 $/MWh
0
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply MarginalCost
1,200W
40$/MWh
Su
pp
ly S
tac
k w
ith
ou
t M
ain
ten
an
ce
(M
W)
Cycling Coal40 $/MWh
Gas Turbines80 $/MWh
NGCC60 $/MWh
0
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply MarginalCost
1,200W
80$/MWh
Su
pp
ly -
Nu
cle
ar
Un
it O
ut
of
Se
rvic
e (
MW
)
Cycling Coal40 $/MWh
Coal Steam Partially Loaded
Base Coal
25 $/MWh
UnpreparedSlow Transition
Operational ProblemsAfter the outage it will take hours for the system to reach the least-cost state of operations
All demand will not be served
Least-Cost ResourceStack Before Outage
Least-Cost ResourceStack After Outage
Veselka - 028
GridSchool 2010
Spinning Reserves Help Alleviate Operational Problems Associated with Random Outages
Nuclear8 $/MWh
Base Coal25 $/MWh
0
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply MarginalCost
Su
pp
ly S
tac
k w
ith
ou
t O
uta
ge
s (
MW
)
Cycling Coal40 $/MWh
Gas Turbines80 $/MWh
NGCC60 $/MWh
1,200 MW80$/MWh
0
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply
Su
pp
ly -
Nu
cle
ar
Un
it O
ut
of
Ser
vic
e (M
W)
Cycling Coal40 $/MWh
Base Coal
25 $/MWh
NGCC60 $/MWh
Gas Turbines
1,200 MW Load
80 $/MWh
Fast TransitionSimultaneously Ramp Operations
Spinning ReservesNGCC 250 MWNG Steam 110 MWOil Steam 110 MWGas Turbines 30 MWTotal 500 MW
Veselka - 029
GridSchool 2010
System Operators Need to Make Certain that Ramping Resources Are Available
Nuclear8 $/MWh
Base Coal25 $/MWh
0
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply
Su
pp
ly S
tac
k w
ith
ou
t M
ain
ten
an
ce
(M
W)
Cycling Coal40 $/MWh
NGCC60 $/MWh
Gas Turbines
6 AMLoad
1200 MW
7 AMLoad
1500 MW
0
250
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply
Nuclear8 $/MWh
Base Coal25 $/MWh
Cycling Coal40 $/MWh
NGCC60 $/MWh
Gas Turbines
Old GT120 $/MWh
500
0 Supply
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Nuclear8 $/MWh
Base Coal25 $/MWh
Cycling Coal40 $/MWh
8 AMLoad
1800 MW
Spinning Reserves500 MW
Spinning Reserves500 MW
Spinning Reserves500 MW
NGCC60 $/MWh
Gas Turbines
Old GT120 $/MWh
Veselka - 030
GridSchool 2010
Usually, the Grid Can Accommodate Relatively Small Amounts of Wind Generation
Nuclear8 $/MWh
Base Coal25 $/MWh
0
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply
Su
pp
ly S
tac
k w
ith
ou
t M
ain
ten
an
ce
(M
W)
Cycling Coal40 $/MWh
NGCC60 $/MWh
6 AMLoad
1200 MW
7 AMLoad
1500 MW
0
250
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Supply
Nuclear8 $/MWh
Base Coal25 $/MWh
Cycling Coal40 $/MWh
NGCC60 $/MWh
Gas Turbines
Old GT120 $/MWh
500
0 Supply
250
500
750
1,000
1,250
1,500
1,750
2,500
2,250
2,000
Nuclear8 $/MWh
Base Coal25 $/MWh
Cycling Coal40 $/MWh
8 AMLoad
1800 MW
Spinning Reserves500 MW
Spinning Reserves500 MW
Spinning Reserves500 MW
NGCC60 $/MWhRamp up
due towind decreaseWIND
WIND
Veselka - 031
GridSchool 2010
The Unpredictability of Wind Compounds Grid Integration Problems Forecast of Wind Power Production Levels Can Be Made for the Next Few Days
Source: Iberdrola Renewables, 2009
Eyeballing: Looks pretty good
Mean absolute error is 9.3%
But devil is in the details (ramps)
Veselka - 032
GridSchool 2010
Wind Forecasts Are Far from Perfect in the Short-Term and Much Worse in the Long-Term
Error depends on several factors Prediction horizon Time of the year Terrain complexity Model inputs and model
types Spatial smoothing effect Level of predicted power
Errors in SCADA information and
wind farm operation
Error in meteorological
forecasts
Errors in wind-to-power conversion
process
Phase Error
Magnitude Error
Veselka - 033
GridSchool 2010
Technology Improvements Are Alleviating Some Problems Example: The Danish Horns Rev Wind Farm Is Providing Regulation (Frequency Response) and Balancing Response
Source: Smith et al., IEEE Power and Energy Magazine, Vol. 7. No.2, 2009.
Control Wind Output with Blade Pitch
(Spill Energy)
Veselka - 034
GridSchool 2010
Historical Winter Load Shapes and Wind Generation in the Midwest
Source: http://www.dis.anl.gov/pubs/65610.pdf
Wind ~ 14% of Load
Unit Commitment Study
Veselka - 035
GridSchool 2010
Problem: Given that Wind Forecasts Have Errors, Make an Economic Unit-Commitment Schedule that Is Reliable
Source: http://www.dis.anl.gov/pubs/65610.pdf
Costs: Generation, Unserved Energy, & StartupConstraint: Ramping, Up & Down Time, Min Output, & Maintain Reserves
Wind can be curtailed (spilled energy)
Veselka - 036
GridSchool 2010
Unit Commitment Results Using Various Modeling Methodologies and Assumptions
Source: http://www.dis.anl.gov/pubs/65610.pdf
Stochastic UC gives higher commitment & more available operating reserves
Similar result for deterministic UC w/additional reserve requirement
Veselka - 037
GridSchool 2010
Comparison of Costs (30 day simulation)Results Based on Fixed Unit Commitments and Real-Time Economic Dispatch
The potential value of forecasting illustrated by perfect forecast (D1) Deterministic UC with point forecast (D2) appears too risky Deterministic UC w/add reserves (D3) and stochastic UC (S1) give similar total cost
Source: http://www.dis.anl.gov/pubs/65610.pdf
Veselka - 038
GridSchool 2010
Finding the “Best” Mix of Generating Capacity to Backup Variable Resources While Keeping Costs Reasonable Is Challenging
Technology Construction Cost Operating Cost* Operating Flexibility**
Fossil Steam 2 4 2
Hydroelectric 2 3 4
Combined Cycle 3 3 3
Gas Turbine 5 2 5
Diesel Generator 4 1 5
Nuclear Steam 1 5 1
Desirability Rating1 Very Low2 Moderately Low3 Average4 Moderately High5 Very High
* Operating costs includes fuel costs and fixed and variable operating and maintenance costs** Operating flexibility is the unit’s ability to respond to load changes and includes ramp rates, cold start time, etc.
Variability Issues
Zero Fuel Costs
Veselka - 039
GridSchool 2010
Suggested Reading: DOE’s 20% Wind by 2030 Report
Explores “a modeled energy scenario in which wind provides 20% of U.S. electricity by 2030”
Describes opportunities and challenges in several areas Turbine technology Manufacturing, materials, and jobs Transmission and integration Siting and environmental effects Markets
Enhanced wind forecasting and better integration into system operation is one of the challenges DOE is funding several research projects in this
area
Veselka - 042
GridSchool 2010
Reserve Capacity Is Needed to Serve Load when One or More Generators Are Out of Service
Peak Load Forecast
Years
MW
Upper RM
Lower RM
Total System Capacity
Existing System Capacity
New Capacity Additions
Engineering GuidelineBuild 15% to 20%
more capacity thanthe peak load
Veselka - 043
GridSchool 2010
Variable Resources Have a Capacity Value Which Can Be Approximated Using Probabilistic Methodologies
Probability of 3 sixes = 1/6 x 1/6 x 1/6 = 1/216 = less than %0.5
Veselka - 044
GridSchool 2010
Loads Can Also Be Viewed as Probabilistic Events Step 1: Chronological Loads
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
Max Load
Min Load
Veselka - 045
GridSchool 2010
Sorted Summer Load ProfileStep 2: Load Exceedance Curve
hr4
hr 17
Lo
ad (
MW
)
Max Load
Min Load
Time
Lo
ad
Some Information Is Lost Such as Load Changes Over Time
hr17
hr4
0 100Exceedance Probability (%)
Veselka - 046
GridSchool 2010
NGCC
GT
Cycling Coal
Base Load Coal
Nuclear
Unit Production Levels Can Be Estimated Using a Load Duration Curve
0 100Exceedance Probability (%)
Lo
ad (
MW
)
Max LoadIs NeverExceeded
Time
Lo
ad
Min LoadIs Always Exceeded
Information Such as Unit Ramping and Frequency of Unit Starts/Stops Are Lost
Veselka - 047
GridSchool 2010
NGCC
GT
Cycling Coal
Base Load Coal
When a Supply Resource Is Forced Out of Service Other Resources Are Dispatched to Serve the Load
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
Max Load
Min Load
NuclearForcedOut ofService
Time
Lo
ad
Veselka - 048
GridSchool 2010
NGCC
GT
Cycling Coal
Base Load Coal
Alternatively, the Load Curve Can Be Adjusted While Including the Out-of-service Unit
121 2 543 6 7 98 1110 18 2019 2322 242113 14 16 1715
Hour of the Day
Lo
ad (
MW
)
New Max
New Min
Nuclear
Original Curve
Load not Served by the Nuclear Unit Is Satisfied by Other Units in the Resource Stack
NuclearCapacity
Time
Lo
ad
Veselka - 049
GridSchool 2010
NGCC
GT
Cycling Coal
Base Load Coal
The Same Methodology Can Be Applied to a Load Duration Curve
0 100Exceedance Probability (%)
Lo
ad (
MW
)
Nuclear
New Max
New Min
NuclearCapacity
Original Curve
NGCC
GT
Cycling Coal
Base Load Coal
There Is Some Probability that a Unit Does Not Operate
0 100Exceedance Probability (%)
Lo
ad (
MW
)
We don’t know with certainty if the nuclear unit will be either on or off at some point in the future
NuclearCapacity
EquivalentLoad CurveAccountsfor NuclearOutages
Nuclear
Weighted Average Curve of Nuclear Unit On & Off
Nuclear OffNuclearOn
Area = Outage Rate/100 X Nuclear Capacity
Likewise All Units Are “Convolved”Into the Load Duration Curve
Exceedance Probability (%) Nuclear
NGCC
GT
Cycling Coal
Base Load Coal
0 100
Lo
ad (
MW
)
Operating System Capacity
Nuclear
Cycling Coal
Base Coal
GT
NGCCEnergyNot Served
Original Curve
Total Capacity + Peak Load
Final EquivalentLoad Curve AccountingFor All Unit Outages
Loss of Load Probability
Exceedance Probability (%)0 100
Lo
ad (
MW
)
Without Wind
With Wind
Using Historical Hourly Wind Data and Corresponding Hourly Loads by Location a Net Load Exceedance Curve Can Be Constructed
There Is a chance that all wind turbines produce zero power at the time of peak load
There Is a chance that all wind turbines produce maximum power at the time of minimum load
The Firm Capacity Credit for Wind Can Be Based on a System Reliability Measure
Exceedance Probability (%)0 100
Lo
ad (
MW
)
Operating System Capacity
Total Capacity + Peak Load
Nuclear
Cycling Coal
Base Coal
GT
NGCC
Firm Capacity Credit (% of Capacity)
Wind: 5-20Coal: 80-95
Nuclear: 90-95NGCC: 85-90
Without Wind
With Wind
Loss of Load Probability
Reliability Increase with Wind
Wind FirmCapacityCredit
Engineering GuidelineTypically 5% to 15% of wind turbine capacity is applied toward the reserve margin
Years
MW
Capacity Credit
De
sig
n C
ap
ac
ity
Derated
Veselka - 054
GridSchool 2010
A Lot of Wind Capacity Is Needed to Meet Renewable Portfolio Standards (e.g., 20% Energy)
0
10
20
30
40
50
2010 2015 2020 2025 2030 2035
Cap
acit
y (G
W)
EXISTINGCAPACITY
THERMAL CAPACITYTO BE ADDED
A lot of wind capacity is needed to get a relatively
small capacity credit
WINDCAPACITYCREDIT (20%)
In this example, wind installed capacity is greater than the thermal capacity additions
Veselka - 055
GridSchool 2010
In Addition to Hourly Operations, Variable Resource Technologies Will Affect both the Amount and Type of New Thermal Capacity Built in the Future
Lev
eliz
ed C
ost
($)
Capacity Factor (%)
0 100
GT NGCC Coal Nuclear
1000
No
rmal
ized
Lo
ad (
%)
Nuclear
Coal
NG
CC
GT
Exceedance Probability (%)
Without Wind
With Wind
100
Veselka - 056
GridSchool 2010
The “Optimal” Expansion Solution in Terms of Economics Can Be Approximated with More Sophisticated Mathematical Models
Pre-planning– existing plus committed units
Planning period (20+ years)– first year an uncommitted unit could
operate Post-planning period
– operate plants past last year– compute salvage value
A Dynamic Programming (DP) AlgorithmIs One Method for Solving Problems
Time Years
State
(Expansion O
ption)
“Best” Plan Over Time
Important Considerations Existing grid resources Unit operating flexibility Ancillary services Wind variability & uncertainty Technical minimum output levels Transmission constraints Load profiles and uncertainty Fuel costs …..