Technical Advisory Subcommittee Quarterly Meeting August 15-16, 2016 Tom Miller, TAS Chair Western Electricity Coordinating Council

Agenda item5- Contingency Reserves Western Electricity Coordinating Council

Contingency Reserve Modeling SOURCE: TEPPC 2026 Common Case Release Notes Hourly Flexibility Reserve: manages the variability and uncertainty associated with variable generation resources like wind and solar: proxy for regulation and load following ABB Flex Reserve Tool SOURCE: Xiaobo Wang- CAISO Reserve Modeling Pertinent to FERC Order 789 Western Electricity Coordinating Council

Flexibility Reserve Update Flexibility Reserves Component Reflect the coincidental system variability and are unique to the reference day data Impact unit commitment in the PCM simulations Composite Reserves shortfalls may indicate system reliability issues Concern is that using Flexibility based on old data may result in compromised results from the 2026 Common Case Stakeholders have depended on WECC to have these calculations in the data-set ILLUSTRATIVE EXAMPLE Western Electricity Coordinating Council

Western Electricity Coordinating Council Questions or Comments Western Electricity Coordinating Council