1. Long Term Study Task Force Update Seeking Software Solutions: Analysis of Future System Operational Reliability Requirements

2. Background LTS Certain scenarios studied as part of the LTS suggest the potential for dramatic changes to the future ERCOT resource mix. A complete evaluation of increasing proportions of non- traditional resources must consider the operational needs of the system to maintain adequate reliability. ERCOT is finalizing a Request for Proposal to procure one or more tools to determine the adequacy of a potential future resource mix to meet operational reliability requirements.

3. Divergent Resource Mixes by Scenario Future scenarios will include different mixes of resources –Some with specific availability profiles –With unique ramping capabilities –Each scenario must provide sufficient operator control to maintain adequate grid reliability LTS

4. Proposal Requirements ERCOT is seeking new tools to ensure that potential sets of resources can provide sufficient flexibility to meet the operational requirements to maintain grid reliability. ERCOT is open to considering a variety of potential solutions. However, the tool(s) must: –Allow the user to test scenarios with resource portfolios composed of increasing amounts of variable generation, energy storage devices, and demand side resources –Quantify the overall capability of the resources in each scenario to meet the reliability needs of grid operations –Quantify system needs and resource capabilities independent of the current set of ancillary service products LTSNovember 18 th, 2011

5. Characteristics of a Reliable System LTS Maintain System Frequency in accordance with current NERC standards Adequately control for risks due to unforeseen future occurrences Example: system resources must provide for timely replacement of lost resources due to unit outages or unit variability

6. Schedule Present concept to LTSF, DSWG, ETWG, and other stakeholders Finalize RFP document with stakeholder feedback by end of January, 2012 Post RFP on ERCOT.com Review proposals / select proposals LTSNovember 18 th, 2011