Solar energy, PV and Concentrated Solar Power (CSP), meets 6.4% of California's electricity demand in June

Chabot also found that PV production peaked at around 4.15 GW mid-day on June 1st, with CSP supplying another 620 MW. This allowed the two sources together to peak at around 19% of the state's electricity demand.

This analysis relies on data from California's grid operator, which does not include behind-the-meter solar PV, including residential and small commercial systems. GTM Research estimates that these represented another 2.617 GW of capacity at the end of the first quarter of 2014.

Electricity generation from CSP was much more even during June than in previous months. Most days the state's CSP plants produced over 5 gigawatt-hours (GWh), and only on June 26th did production drop below 2 GWh over the full day.

Chabot argues that CSP is a more appropriate technology for meeting California's electricity needs, but says that new CSP plants should incorporate storage.

“Daily solar PV production was very stable in June and much less sensible than the solar thermal  production to the variation of the monthly daily and hourly meteorological and solar irradiation conditions,” notes Chabot.

“This result confirms that future solar thermal power plants should be built only with storage capabilities in order to present at least the same electricity system integration performance than PV plants.”

Overall, renewable energy including large hydroelectric plants met 28.8% of California's electricity demand during June. This was driven by higher wind and solar output, which has allowed renewables to meet a larger portion of demand despite increased electricity use.