2009 Scenario Reliability Assessment - NERC

Scenario Reliability Self-AssessmentsIt is a price taker, it does not participate in the day-ahead market, and it is exempt from deviationpenalties. Conventional generation typically dispatches around wind generation.As wind penetration increases, there would be occasions when wind would need to participate incongestion management, which can occur through operating guides, the use of SPSs, TLRprocedure, or curtailment of wind generation. With the Production Tax Credit of $19/MWh(after tax), the wind plants can economically generate even with a negative Locational MarginalPrice (LMP) as low as about -$29/MWh (before tax).Ultimately, wind generation would likely participate in the day-ahead markets. This can beaccomplished to a large extent with accurate forecasting. The Midwest ISO has 24-hour windforecast, which is typically within plus or minus 10 percent of actual levels. Wind generation, toa reasonable extent, can be controlled so as to limit ramp rates, perform fast runback forcontingencies, etc. However, it would require the integration of wind farm management systemswith Market operator dispatch signals.Reliability Assessment AnalysisIt is assumed that new wind facilities to be integrated onto the MRO footprint would complywith FERC Order 660-1A which addresses the need for low-voltage ride-through capabilities andreactive power capabilities of individual wind turbines. In the Midwest ISO, reactive poweranalysis is one integrated part of every individual Generation Interconnection System ImpactStudy. No wind plant can be granted interconnection services without mitigating the incrementalreactive support problem it would cause. The Midwest ISO Ancillary Service Market and theMidwest Contingency Reserve Sharing Group provide financial incentives and legal obligationsto ensure the entire Midwest ISO system has adequate frequency response support in both theshort term and long term. The Midwest ISO believes wind forecast accuracy is critical tominimizing unexpected ramps in wind production, which in turn would minimize therequirement for additional reactive and frequency support requirements. Generatorcharacteristics would be reviewed to identify more responsive units, which also may alleviatereactive or frequency response issues.The Midwest ISO is actively working with its stakeholders to determine the best solution to beable to incorporate large amounts of wind. Accurate wind forecasts for the Day Ahead marketprocess and accurate and timely updates during the operating day would need to occur in order toincorporate wind generation into the day-ahead market. Equitably allocating costs for reservesharing would also need to be developed.2009 Scenario Reliability Assessment Page 51