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2013 Ancillary Services Methodology. Chad Thompson, ERCOT QMWG December 4 th , 2012. Proposed Changes. Remove Non-Spin Load Forecast Bias Consider Net-Load Error from all Intermittent Renewable Resources. NSRS Load Forecast Bias - Background.
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2013 Ancillary Services Methodology Chad Thompson, ERCOT QMWG December 4th, 2012
Proposed Changes • Remove Non-Spin Load Forecast Bias • Consider Net-Load Error from all Intermittent Renewable Resources
NSRS Load Forecast Bias - Background • The NSRS Load Forecast Bias was implemented in Zonal due to the lack of an hour-ahead commitment tool • Since Nodal Go-Live, the number of DRUC commitments issued by ERCOT has diminished and are very rare • ERCOT is opting to utilize HRUC for committing Resources, waiting until closer to the Operating Hour to issue commitments to allow QSEs to self-commit Resources in lieu of receiving an HRUC instruction
NSRS Load Forecast Bias – Effects of this change • 2012, Jan-Nov, was evaluated with the Bias removed • Observed that some months’ minimum NSRS requirements remained unchanged while others observed a decrease • Fewer periods of over-forecasted conditions have been observed • The decreases observed were not always across the same hour blocks • The result, on average, is a reduction in the requirement by 120 MW per hour • The effects on the hourly monthly averages are on the next slide
Consider Net-Load Error from all IRRs • With the planned continued addition of non-wind IRRs, ERCOT believes it is necessary to incorporate the error that these technologies introduce into our NSRS analysis • Continue to use the results of the 2007 GE study, which were developed for wind, as the standard until an ERCOT study can be conducted with regards to error associated with other IRR technologies • Effect • Minimal impact, as the penetration of these IRRs compared to wind at present, is small