On 100 out of the 144 days since 8 March, California’s electricity demand was 100% supplied by renewable energy for at least part of the day. Solar, wind and hydroelectric energy technologies fully powered the state’s grid for at least a few minutes and for as long as ten hours for 100 days.

Steven King, clean energy advocate at Environment California, said: “This remarkable milestone in California is proof for our nation and the world that clean energy is more than capable of fulfilling our electricity needs. The days that renewable energy sources power 100% of the electric grid are becoming more common by the month. Someday soon, solar and wind power will provide 100% of our energy needs all day, every day.”

In a press release, Environment California highlighted that California became the first state to reach 100% clean energy, and 12 additional states have also made the pledge since. California, Hawaii, Washington and New Mexico are working towards fulfilling this promise by 2045, while Connecticut, New York, Minnesota, Oregan and Michigan are aiming for 2040.

Johanna Neumann, senior director of the Campaign for 100% Renewable Energy at Environment America, said: “We hope this achievement in California will encourage every state to get on board with 100% renewable energy.”

Despite the optimistic tone of Environment California, fossil fuels are currently still necessary to ensure backup power is available in times of specifically high demand or limited supply, given the temperamental nature of renewable energy sources. This was the case for two weeks in July when California experienced heatwaves, requiring fossil fuel plants to power the grid for every minute of the day.

To overcome such scenarios and reach the 100% renewable energy target, Environment California recommends further deployment of solar panels, off-and-onshore wind turbines, hydroelectric power and storage batteries to sustain the grid.