SAN FRANCISCO (KGO) -- As the nation gears up for the largest solar eclipse since century, the people who run California's power grid are getting ready for a big dip in energy production.
When the moon passes the sun on Monday it will be spectacular, but it will also create a challenge for the state's energy producers.
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"What we are going to see through the solar eclipse is of greater magnitude than what we've seen before," said Steven Greenlee with California Independent System.
During the eclipse, the moon's partial shadow will obscure 90 percent of the sun in the northern part of the state and 60 percent in the south. That shadow will reduce solar power generation enough to worry state regulators about keeping the state's lights on.
"That could lead to up to a 6,000 megawatt reduction in solar production on Monday morning," said Ed Randolph with the California Public Utilities Commission.
That's enough to power 6 million homes.
Thanks to the speed at which the solar industry has grown, solar power is now a daily player in the state's overall energy production, making up as much as 40 percent of the state's overall power supply on any given day.
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The solar eclipse could cut that in half.
'The utilities and the grid operator have been planning for this for over a year, we have the resources to back it up it shouldn't create any further reliability problems," said Randolph.
The state PUC says much of the demand during the eclipse will be met with other clean energy sources including natural gas, and hydro-electric power.
"We'd like to encourage customers to help manage the load, to help reduce the stress on the grid, by conserving themselves," Randolph said.
The PUC is asking you to turn off lights, and unplug unused electronics and appliances you don't need leading up to and during the eclipse.
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"On Aug. 19, you know, millions of Nest customers are going to see their thermostat light up," said Ben Bixby with Nest Labs.
Bay Area "smart" thermostat maker Nest will also help you reduce the load on the energy grid during the eclipse.
"IF they are in an eligible area, they are going to be invited to participate in the first ever nest solar eclipse rush hour," Bixby said.
Nest thermostat owners will have the choice to opt-in. If they do, the thermostat will automatically respond as the eclipse approaches. If needed, it will cool the home ahead of the eclipse by turning off air conditioning as the moon passes the sun unless it is absolutely needed.
"Ideally we will have offset everything, so that you're sitting comfortable for the full duration of the eclipse," Bixby said.
So all you will have to do is sit back and watch. Besides, who needs to turn on the lights when the best show in town will be the darkness?
On the day of the eclipse, we'll bring you live coverage on TV and online. Click here for other stories, videos, and photos on this rare celestial event.