By Velena Jones

SACRAMENTO (CBS13) – There’s growing concern that this week’s heatwave could disrupt California’s power supply.

Managers of the state power grid have issued a Flex Alert beginning Thursday at 5 p.m. Many wonder if we will see rolling blackouts like last summer.

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It’s an urgent call for conservation as California faces uncertain energy supplies in the coming days.

“We’re in a very extreme heat situation right now,” a spokesperson for the California Independent System Operator  (CAISO) said.

CAISO said the state is facing a 300-megawatt shortfall in electrical supply.

“We ask consumers to shift the use of their energy, increase their thermostat to 78 degrees, avoid those major appliances,” CAISO said.

Last summer, California saw stage-three emergency blackouts for the first time in nearly 20 years. More than 800,000 customers abruptly lost power during two days in August. Officials blamed the extreme heat and a lack of available power in other states as being the primary causes.

But could it happen again this year?

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“The hope is we don’t get there in the first place and there’s a lot of people working real hard to make sure we don’t,” Brian Ferguson with CAISO said.

So what has been done to prevent more rolling blackouts?

“3,000 to 3,500 megawatts of additional capacity will be available this summer,” CAISO said.

Utilities like Pacific Gas and Electric are adding battery storage, using Tesla lithium-ion power packs that can save up excess solar power during the daytime and make that energy available later in the evening when demand is still high. And during last year’s blackouts, electrical circuits had to be manually disconnected. This year, that procedure has been automated.

“I will help us impact fewer customers and restore power more quickly,” said Megan McFarland with PG&E.

But grid managers say there are still a lot of unknowns about this summer – with the drought causing reduced hydroelectricity and potential fires, which could damage transmission lines.

“We have a multi-faceted challenge that we’re facing,” Ferguson said.

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Thursday’s Flex Alert is for 5 p.m. to 8 p.m. Stage one emergencies are not issued until energy reserves drop below 7 percent and rotating outages are ordered when reserves approach 1 percent.

Velena Jones