Bruce Rew, SPP’s senior vice president of operations, predicted a year ago that there was “a good chance” the RTO would reach the 70% barrier for renewable energy penetration.

Rew’s prognostication skills are not in doubt. The RTO tweeted last week that it met 73.67% of its demand Wednesday with wind, hydro and other non-fossil resources.

The mark came at 2:14 a.m. CT, when SPP’s load was 22.5 GW. Renewable resources suppled 16.5 GW of that power, with wind supplying 65.4% and hydro 8.3%. The grid operator also set a record for wind generation on Sept. 30, when it produced 17,109 MW at 12:30 a.m. That broke the previous mark of 16,972 MW, set Sept. 11.

ERCOT, which has 22,313 MW of installed wind capacity, holds the RTO high for wind generation, set in January at 19,672 MW.

— Tom Kleckner