California Renewables Dream’n

As California considers a 100% renewable-energy mandate, the state’s legislators should be asking what happens to California’s energy profile when the sun doesn’t shine and the winds don’t blow.

In May, the national press hyped how California renewables met a record-breaking 67% of the state’s electricity generation. It happened during the 3 pm hour on Saturday the day before Mother’s Day. We checked the numbers, and sure enough wind, solar, geothermal, and other renewables had a combined output of 14,215 megawatts out of a total generation of 21,390 megawatts in that hour. It was discernibly a sunny day with the hours of highest penetration of renewables between 8 am and 7 pm.

No doubt, the timing of this impressive event was opportune.

Also in May, California’s Senate was considering passage of SB 100, a bill which seeks to accelerate the state’s renewables mandate to 50% by 2026, 60% by 2030 and 100% by 2045. What better way to convince idealistic legislators to enact a 100% mandate when the state has already skipped past the current 50% by 2030 threshold? At this rate, why not mandate 110%, 200% or better?

Not so fast. The bigger question state legislators should be asking is what happens to California’s energy profile when the sun doesn’t shine and the winds don’t blow. We looked at the hourly energy production figures for May and compared them to January production. The aggregate data shows California is nowhere near meeting its lofty goals.

Fuel Type

January 2017

May 2017







Other Renewables*









*Includes geothermal, biomass, biogas and small hydro
**Includes imports and large hydro

Of the 744 hours represented in January (31 days x 24 hours), 72% (or 537 hours) showed renewables producing less than 20% of the total generation. In May, performance was much better with most hours producing more than 20% renewables, however when we omit solar from the mix in each month, renewables (including wind) produced less than 20% in all but 7 hours in January and less than 20% in most of the hours of May. 


January 2017

May 2017


Generation (MWh)

Hrs Generation <20%

Generation (MWh)

Hrs Generation <20%

WITH Solar


537 Hrs (72%)


200 Hrs (27%)

NO Solar


737 Hrs (99%)


526 Hrs (71%)


The graph demonstrates the failure of wind and solar to perform in January. (Click here to download the graph)

Obviously, policy debates cannot be based on the renewable energy performance in one hour of one day when demand is low. Sacramento could vote all-day long to raise energy mandates but none of those votes will make renewables perform at the levels now being discussed. Banking on storage technology might make up for some of the difference but that’s not proven at the scale needed and the cost will be exorbitant. 

Meanwhile, the push for more transmission is becoming urgent in order to export generation to neighboring states rather than the other way around. As excess megawatt-hours of renewables during the daylight hours collapse real-time market prices, utilities in other states are looking to contract with the California ISO so they can buy the cheap power — that is power that’s heavily subsidized by California ratepayers.

It’s no wonder there’s increasing debate over expanding California’s grid into a regional system.  Meanwhile the economic viability of traditional generators will continue to suffer unless they, like their renewable energy counterparts, can derive benefit from above-market power contracts. Ultimately, it will be California ratepayers that pay the steep price for this impossible dream.

California Senate President Pro Tem, Kevin De León, touts his bill as a jobs creator. Maybe so, but before he and his fellow legislators ram this policy through, they owe it to their constituents to wake up from the renewable energy fantasy and recognize the truth right in front of them.

[Editor's update: On June 26, the California Assembly amended SB 100 to include non-carbon emitting generation such as nuclear and large hydro. by Sep 2017 the bill failed after various stakeholders questioned the feasibility and the need for 100% renewables.] 

JUL 18 2017
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