ERCOT announced it is terminating its reliability-must-run agreement for NRG Texas Power’s Greens Bayou Unit 5 in Houston, effective May 29.
The grid operator said studies using new criteria indicated the unit would not be needed for transmission system reliability after Exelon’s 1,148-MW Colorado Bend II Generating Station in Wharton County, Texas, becomes operational in June.
The new criteria took effect with the passage of Nodal Protocol Revision Request 788 last fall. NPRR 788 requires a potential RMR unit to have “a meaningful impact on the expected transmission overload” to be considered for an agreement.
ERCOT said the previous rules, which used a forecast based on a 90% probability of exceedance, were overly conservative and that the new criteria should reduce the use of RMR contracts for reliability concerns that have a very low probability of occurring.
The RMR, ERCOT’s first since 2011, was approved last June to run through June 2018. Greens Bayou 5 is the largest of seven units at NRG’s Harris County complex. Built in 1973, the 371-MW natural gas unit was mothballed in 2010 and 2011, but returned afterward. (See “Greens Bayou Still Needed Under RMR Protocol Changes,” ERCOT Board of Directors Briefs.)
– Rich Heidorn Jr.
