WASHINGTON, Aug 27 (Reuters) - Texas' electric grid operator asked residents and businesses to conserve energy on Sunday as its reserves were expected to decrease during a scorching heat wave that has caused demand to surge.

The Electric Reliability Council of Texas (ERCOT) issued an appeal for conservation from 4 p.m. to 9 p.m. local time (2100-0200 GMT) on its website, saying reserves could run low due to high demand and a lack of wind and solar power generation.