By Tom Kleckner

ERCOT said Friday it has executed a reliability-must-run (RMR) agreement to keep a 371-MW natural gas-fired generator available through September, with the likelihood of extending the contract through June 2018.

NRG Texas Power’s Greens Bayou Unit 5 was to be mothballed June 27. However, it will now be made available to the ERCOT market from June 1 through September. Under the RMR agreement’s terms, ERCOT will make a standby payment to NRG of $3,185/hour during on-peak hours, regardless of whether the unit runs.

ERCOT said the agreement will ensure transmission stability in the Houston region. The ISO said last month it has enough generating capacity to meet its expected demand into the next decade, even with NRG’s announcement it would mothball Greens Bayou. (See “ERCOT Reports Show Ample Capacity into Next Decade,” ERCOT Briefs: Ample Capacity; Outage Procedures.)

The Texas grid operator will ask its Board of Directors to approve an extension to the agreement for the summer of 2017 and June 2018 during its June 14 board meeting. If the board rejects the extension, the RMR agreement will expire May 31, 2017.

The ISO said it expects the $590 million Houston Import Project, which will improve the region’s ability to draw power from elsewhere in Texas, to be completed by the 2018 summer peak. The RMR agreement does not include off-peak periods (October through May) because planning studies do not indicate Houston-regional reliability violations during that period.

The RMR agreement is ERCOT’s first since 2011. It has executed 73 other agreements since 2002, most of which were for transmission stability. Four RMR agreements in 2011 returned mothballed units to service because of anticipated generation shortages during that summer’s peak demand period.

Greens Bayou 5 is the largest of seven units at the Harris County complex. Built in 1973, it was mothballed in 2010 and 2011, but returned afterward.