Integration of Wind Energy: Study Results and Recommendations for Black Sea Regional Transmission

2. Wind Integration Study Results and Recommendations Black Sea Regional Transmission November 11, 2010 Bruce Rew, P.E. Vice President of Engineering

3. WITF Study Overview • Goal: Determine operational and reliability impacts of higher wind generation in SPP • Assessed impacts in three major areas: • Transmission • Operations • Markets

4. WITF Study Overview • Detailed studies for three levels of wind penetration • Base case- current 4% wind penetration • 10% case- 10% wind penetration • 20% case- 20% wind penetration • Each case provided recommendations

5. Major Findings • There are no significant technical or reliability barriers to integrating 20% wind, provided sufficient transmission is built • Increase in wind changes power flow patterns – particularly from west to east • Wind integration would be greatly facilitated by: • Consolidated Balancing Authority • Sophisticated unit commitment process • Centralized forecasting system

6. WITF Recommendations: • Transmission upgrades • Reliability/markets • Ancillary services • Forecasting • Unit commitment • SPP policies

7. Recommendations: Transmission Upgrades • Major transmission reinforcement is necessary to accommodate as low as 10% wind penetration • Needed for 10% case: 1,260 miles 345 kV 40 miles 230 kV lines • Needed for 20% case: Additional 485 miles 765 kV766 miles 345 kV205 miles230 kV25 miles115 kV

8. Recommendations: Transmission Upgrades • Install voltage control devices for high voltage lines, or set minimum flow limits • Add new reactive capability as that provided by wind-displaced thermal units • Proceed with Generation Interconnect cluster studies, but evaluations should be done for entire region • Coordinated planning between wind generation and transmission is essential

9. Recommendations: Reliability/Markets • Consolidate SPP into single Balancing Authority • Reduces overall needs for reserves and flexible resources • Greater operational flexibility • As forecast errors increase, need for flexible units increases • Robust transmission system could reduce local generation requirements • Explore ways to increase diversity in wind resource base

10. Net Load Ramping Needs

11. Recommendations: Ancillary Services • Separate regulation-up and regulation-down • With higher wind, regulation-up and regulation-down requirements are not symmetrical • More wind increases need for regulation capability and requirements • Wind regulation needs can be reduced by improved forecast accuracy • Load-following reserves may become beneficial as net load forecast variability increases

12. Recommendations: Forecasting • Implement centralized forecasting system • For unit commitment and reliability assessment • Employ multiple methods and vendors • Forecast errors increase startups of flexible units and reduce generation of less flexible units • Wind under-forecasts have larger impact on wind curtailment than over-forecasts • Specific-purpose forecasts should be procured for difficult operational situations • Separate from centralized forecast system

13. Recommendations: Unit Commitments • Supplement day-ahead with intra-day (four hours ahead) • Unit commitment capability is key to wind integration • Operational flexibility • Enhanced ancillary services • Accommodation of forecast errors • Align unit commitment with wind forecast methods • Establish new reserve requirements to parallel enhanced unit commitment practices

14. SPP Policies: Regulation Requirements • Adopt more frequent update of requirements, such as daily, hourly, or even sub-hourly • Align determination of regulation requirements with unit commitment • Daily update should consider load and wind forecasts • Proceed with reducing the balancing market clearing time from 15 to 10 minutes ahead • 10-minute dispatch will significantly decrease need for ancillary services

15. SPP Policies: Market • Provide incentives for wind units to react to market • Consider rules that provide incentives for wind plants to provide reactive support • More critical as wind levels increase and more conventional generators become displaced • Separate pricing and provision functions of up and down regulation requirements • Expand market boundaries • Larger area allows SPP to leverage load and resource diversity and lower impact of high wind

16. SPP Policies: Additional • Shorten reserve replenishing timeframe • Integrate advanced energy storage technologies • Establish a centralized outage control system

17. Next Steps • Study did not include determining optimum level of transmission expansion • Results of the study could be used as the basis for the analysis of the optimum transmission expansion necessary for wind generation in SPP footprint