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Diablo Canyon closure shows California’s power grid is changing fast

California’s system for producing, moving and using electricity is changing fast.

And apparently it no longer has room for a nuclear plant.

Pacific Gas and Electric Co.’s surprise decision to shut down Diablo Canyon, the last nuclear plant in California, came after the company squinted at the future and realized that the massive facility would be an awkward fit.

When Diablo opened in 1985, big plants produced large amounts of electricity and fed it to a grid where power basically flowed one way, from generator to customer. Think of water pouring through a network of pipes to numerous taps: Utilities controlled the whole flow, from source to sink.

Now, many businesses and homeowners produce their own energy. A solar array is installed in PG&E’s territory every six minutes. Many generate more electricity than they need during the day, feeding the excess back onto the grid.

Huge amounts of solar power flood the grid at midday, falling off sharply in late afternoon. Wind power surges at night. Power flows fluctuate with the weather.

And a fast-growing number of cities and counties — including San Francisco, PG&E’s hometown — are buying electricity on behalf of their citizens through a system called community choice aggregation, partially bypassing the utilities.

Nuclear plants of Diablo’s generation were designed to ramp up to full throttle and stay there day and night, providing “baseload” power for the grid. But that, increasingly, is not what California needs.

“We’re transitioning, clearly, to a distributed system where you rely less and less on those big resources and more on distributed resources,” said Stephen Berberich, CEO of the California Independent System Operator, which manages the grid.

“You need a flexible fleet that can start and stop quickly,” he said. “The way California is headed, big, baseload power isn’t as valuable as it was.”

Role of utilities

These changes are also altering — in some ways, diminishing — the role of utilities within the state.

They once owned almost all the electricity system, from plants to power poles, and faced no real competition within their territories. Now, other companies own most of California’s power plants, while the utilities retain the transmission and distribution wires.

And with cities and counties getting into the power-buying business, PG&E and its peers will find themselves delivering power produced and purchased by others. It’s not a fate they wanted, but it’s happening anyway.

Read full article at SanFrancisco Chronicle