For the first time in history, on March 11 California became the first state to power more than half the power it needs from the sun.
Since power levels fluctuate depending upon a multitude of factors, the record only lasted for a few hours. But it is a significant milestone.
The record was set when almost 40 percent of the electricity flowing across the grid came from large-scale solar power plants. The remaining solar power came from a variety of smaller sources, including private homes and businesses.
The US Energy Information Administration said much of the power came from utility-scale solar photovoltaic farms, solar thermal plants, and the panels installed on private homes.
Just 15 years ago, the state produced almost no power from solar at all. The new solar advancements have had a big impact on wholesale energy prices, which dipped to zero or even to negative territory this spring during certain hours in California.
Negative prices usually happen because there’s a glut of renewable energy, but non-renewable generators are also producing. (They don’t shut them off completely because of the high costs of restarting.)
California now accounts for a large part of the US energy market, having the highest energy demand of any state after Texas. It also has almost half of all the solar power in the US.
Some of the surge is seasonal. Spring tends to have temperate weather, meaning the demand for power used for heating and cooling is lower. So while solar cells will produce more energy in the summer, there’ll also be a lot more power used.
Although the surge in renewable power is a key part of California's fight against climate change, it creates its own set of problems. California produces so much solar power on bright summer days that some is shunted off the grid, in a process known as curtailment.
"We're seeing the potential for more curtailment this summer," Independent System Operator spokesman Steven Greenlee said. "The thing is, we're seeing this happen sooner than our initial analysis suggested."