(Bloomberg) -- California is facing electricity shortages as abnormally high temperatures and plant outages challenge a region already grappling with limited natural gas supplies and a drought. Power prices surged on Wednesday to the highest level in almost two years.

Calls to conserve energy

The manager of the state’s power system called on generators to suspend maintenance through Friday night, while also asking consumers to conserve energy. More than 3,700 megawatts of power generation capacity was offline Wednesday, up 19 percent from a day earlier, according to the California Independent System Operator.

The threat of shortages on Wednesday adds to the mounting challenges that California’s power market is facing this summer. The state has warned that Southern California may see blackouts on as many as 14 days after a massive natural gas leak at a Sempra Energy complex limited supplies to electricity generators.

Historic drought

PG&E Corp. has also had to close some storage wells, and a historic drought has plagued the western U.S. in recent years, curbing hydropower resources.

“With high loads, some forced plant outages and reduction in import capacity, it is expected to be a tight day system-wide,” Steven Greenlee, a spokesman for the California Independent System Operator, said by e-mail Wednesday.