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Anjali Sheffrin, Ph.D.Chief Economist & Director, Market Design & Product Development
Integration of Wind Resources in CAISO Markets and Grid
Operation
APEx 2007 ProgramOctober 15-16, 2007
2 Anjali Sheffrin
Individual States take lead in fight against global warming
“Today California will be a leader in the fight against global warming,” said Governor Schwarzenegger. (United Nations' World Environment Day conference in San Francisco, June 1, 2007)
Renewable Portfolio Standards
4 Anjali Sheffrin
CAISO Renewables Integration Program
ISO Corporate Goal: Support the integration of renewable resources on the California power grid in support of the State of California’s policy regarding renewables.
Project encompasses the integration of renewable resources into CAISO’s Transmission planning Markets, and Grid Operations
Objective is to support the State’s goal of 20% of customer load being served by renewable resources by the end of 2010 and 33% by 2020.
5
Summer 2006Solar 0.4%
Small Hydro 1.4%
Wind 2.4%BioMass 1.5%
Other Generation Resources
91.0%
Renewables Provided 9% of the Energy to Serve Customer Loadfor the period May through September
Geothermal 3.3%
Current Level of Renewable Generation in California
6
Existing California Renewable Generationand Possible Additions to meet the 20% RPS Goal by 2010*
1,977
465
1,214
228
4,577
1,300
845
2690
-
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
Geothermal Biomass Wind Solar
MW Additional
Existing3,191 MW
1,073 MW
7,267 MW
1,765 MW
* Data on additional renewable resource is based on a current CEC studies on renewables. Potential retirements of existing resources and repowering projects are not included.
13,296 MW Total Renewables 7,319 MW Additonal 5,977 MW Existing
20% Renewables
7
Large amounts of renewable generation are needed to meet state requirements.
0
5000
10000
15000
20000
25000
2007 2010 2020
Year
Me
ga
wa
tts
Wind Geothermal Biomass Solar
Current
20%
33%
8
Altamont Pass
Solano County
Tehachapi/ Mojave Desert
San Gorgonio Pass
California’s abundant wind resources have a key role to play.
Pacheco Pass
Lassen
Shasta
Salton Sea Imperial Valley
9
What are the Major Challenges of Integrating Intermittent Resources ?
Barriers to Efficient Interconnection and Transmission Planning Funding challenges for transmission to remote locations and
existing transmission policies distinguishing reliability and economic upgrades
Operating Issues Frequency regulation, load following, and operating reserves;
Ramping problems; over generation control
Importance of forecasting of renewable energy;
Application of WECC standards for wind generators
10
Removing Barriersto Efficient Interconnection Policies
Problem: Current Interconnection Policies Creating a Barrier Long standing FERC policy offers two approaches for financing transmission upgrades:
• Network transmission facilities rolled into Transmission Access Charge
• “Tie-line” facilities paid for by power plant owners
CAISO proposed solution: Distinct new category of transmission serving multiple power plants in areas where the energy sources cannot be transported
Facilitate capturing economies of scale associated with renewable energy development
Promote overall development of diverse renewable resource opportunities
Key elements of new interconnection policy for locationally constrained resource areas
Financing Mechanism Allows Appropriate Sizing
• Lines paid for by transmission owners
Risk of Stranded Costs Systematically Mitigated
• California Energy Commission designation as a significant resource area
• Multiple projects in the area
• CAISO must find the project to be cost-effective
11
Eligibility Criteria for Transmission to Locationally Constrained Resource Areas
Must be non-network
Must provide access to an area with significant potential for development of locationally constrained resources (i.e., renewables) as designated by the CEC
Must be turned over to ISO control
Transmission to serve multiple facilities
Cannot exceed 15% of the sum total of the high-voltage network plant included in the Transmission Access Charge
Must meet a commercial interest test - i.e. sufficient generator interest through Large Generator Interconnection Process
12
Removing Barriers to Effective Transmission Planning
Problem: Planning for reliability upgrades only and economic upgrades to be market driven
ISO proposed solution:
New transmission planning process for reliability and economic projects
• Regional planning with all transmission providers in California
• Established Transmission Economic Assessment Methodology (TEAM) as standard measure for establishing economic need for major transmission projects
Proactive transmission planning for future clusters of renewable generation
• Tehachapi Transmission Plan
» Approved on January 24, 2007
» First use of clustering approach
13
Transmission Study Results
The Tehachapi Transmission Plan is sound and there are no serious transient stability or voltage control problems
Key conclusions
Power factor control is critical - New wind generators must meet WECC criteria for ±0.95 power factor control
Low Voltage Ride Through Standard – all new units must meet WECC LVRT Standard.
New wind generators should be Type 3 or Type 4 units
Existing Type 1 Wind Generators in Tehachapi area do not meet LVRT standards and will probably be lost in event of voltage collapse
14
Ramping issues
Forecasted Hourly Ramps due to Additional Wind Generation
• In California, the wind generation energy production tends to be inversely correlated with the daily load curve. The wind energy production peaks during the night and falls off during the morning load pick up. The net result will be morning ramps of 2000 to 4000 MW per hour for 3 hours – a total of 6000 to 12,000 MW over 3 hours.
15
Total California Generation
0
200
400
600
800
1000
1200
0:01
1:01
2:01
3:01
4:01
5:01
6:01
7:01
8:01
9:01
10:0
1
11:0
1
12:0
1
13:0
1
14:0
1
15:0
1
16:0
1
17:0
1
18:0
1
19:0
1
20:0
1
21:0
1
22:0
1
23:0
1
MW
TOTAL
Pacheco
Solano
Tehachapi
Altamont
San Gorgonio
Total California Generation
0
200
400
600
800
1000
1200
0:01
1:01
2:01
3:01
4:01
5:01
6:01
7:01
8:01
9:01
10:0
1
11:0
1
12:0
1
13:0
1
14:0
1
15:0
1
16:0
1
17:0
1
18:0
1
19:0
1
20:0
1
21:0
1
22:0
1
23:0
1
MW
TOTAL
Pacheco
Solano
Tehachapi
Altamont
San Gorgonio
Wind Generation Output may Change Quickly
Will Affect Ramp Rates, Regulation Requirements,
Load Following, Etc.
16
January 6, 2005 California Wind Generation
0
50
100
150
200
250
300
350
400
0:00
:00
1:00
:00
2:00
:00
3:00
:00
4:00
:00
5:00
:00
6:00
:00
7:00
:00
8:00
:00
9:00
:00
10:0
0:00
11:0
0:00
12:0
0:00
13:0
0:00
14:0
0:00
15:0
0:00
16:0
0:00
17:0
0:00
18:0
0:00
19:0
0:00
20:0
0:00
21:0
0:00
22:0
0:00
23:0
0:00
MW
20000
22000
24000
26000
28000
30000
32000
34000
TOTAL Load, MW
Wind Generation Output may Peak During Off-peak Periods
May Lead to Cycling of Base Load Generation
17
Operational challenges to incorporating the 20% RPS Target
Increases the amount of regulation resources Add 170 MW to 500 MW of regulation resources to accommodate rapid changes in wind
and other variables.
• Amount required varies with the season (winter, spring, summer, fall)
• Estimated cost of additional regulation is $30 million annually
Ramping requirement increases Fast ramping increases by ±15 MW/min to ±25MW/min
Regulation by hydro units will be most important
Supplemental energy dispatches will increase Morning ramp up will increase by 1000 to 2000 MW per hour
Evening ramp down will increase by 1000 to 1800 MW per hour
Potential Over Generation problems will increase for light load periods
Pro rata cuts of up to 800 MW of wind generation production may be required for an estimated 100 hours per year
18
Enhanced Resource Adequacy requirements and market prices will drive integration of renewables
GenerationPortfolio Storage
DemandResponse
Resources Required for Renewables Integration
Quick Start Units
Fast Ramping
Wider Operating Range
Regulation capability
Shift Energy from off-peak to on-peak
Mitigate Over Generation
Voltage Support
Regulation capability
Price sensitive load
Responsive to ISO dispatches
Frequency Responsive
Responsive to Wind Generation Production
19
How to make the 20% RPS Target work
Build the planned transmission facilities for Tehachapi
Sunrise Power Link
Require all new wind generators to be Type 3 or Type 4 that meet Low Voltage Ride Through (LVRT) Standards
Add SVC’s for dynamic VAR regulation
Change Resource Adequacy requirements for generation facilities for more fast start units, increased ramping, and larger operating ranges.
Integrate wind energy production with changes in hydro dispatch for meet the need for rapid energy ramps
Increase storage options – 3rd pump operation at Helms, Leaps, Compressed Air Storage, H.S. Flywheels for regulation and Hydrogen Storage.
Increase Demand Response options
20
Conclusions
The increasing cost of natural gas for fossil fired plants and declining cost of wind generation makes wind generation an attractive source of energy.
We need new methods to control the wind generation ramps if we are going to accommodate 6000 to 8000 MWs of wind generation.
New technology at the turbines site can provide for response for frequency control.
The regulation and load following burden to accommodate wind generation is not trivial but can be managed with good forecasting techniques and mix of fast ramping generation resources .