California Still Smashing Summer's Solar Power Records

Screen shot 2013-12-02 at 1.16.47 PM-thumb-600x359-64939
Monday, December 2's renewables output as of 1:30 pm | Image: California Independent System Operator

Hey, remember back in August when we last noted California having set a record for the amount of utility-scale solar feeding into the state's power grid? Well, the dark and shortening days of the coming winter haven't slowed the state's momentum, because we just blew past that August record, and a subsequent on set the month after.

At just after noon on Saturday, November 30 the state's utility-scale solar panel arrays were feeding 2,626 megawatts of power into the California grid. That's a fair bit above last record we noted -- 2,573 megawatts on August 9 -- and it also breezes past 2,606 megawatts on September 12.

As far as we can tell, that's the biggest output for the state's wholesale solar panels since tracking began. But the California grid's record for all solar electricity, including solar thermal, may actually have been broken about a month ago.

Story continues below

The California Independent System Operator (CaISO), which runs the power grid for most of the state and part of Nevada, now tracks photovoltaic and solar thermal separately. The state's solar thermal facilities seem to have slept in on Saturday: when the state's photovoltaic panels reached their peak output at 12:10 p.m., California solar thermal facilities were only putting about two or three megawatts into the grid. They'd peak later in the day, putting 144 megawatts of juice into the grid at 3:08 pm.

On November 6, though, the state's utility-scale solar panels and solar thermal facilities were working in closer sync. Just after 11 a.m. that Wednesday morning, CaISO recorded its photovoltaic panel output peaking at 2,609 megawatts. The state's solar thermal facilities had peaked for the day a couple hours earlier, at 181 megawatts. By 11:00 a.m. they were putting out significantly less, at 159 megawatts. Assuming that their production didn't fall too much in the next five minutes, that'd mean somewhere between 2,735 and 2,740 megawatts of total solar flowing into California's grid at the time -- well over the September record.

That's significant because the sun's much lower in the sky in November than it is in August and September. The lower the winter sun gets, the greater an angle at which it strikes us -- meaning that the insolation (solar energy per square meter of surface) is a lot lower. And winter sunlight's traveling through more of the atmosphere to reach us doesn't help. In San Francisco, for example, the solar insolation -- the amount of solar energy striking each square meter of surface -- is about a third less between November and April what it is from May through October.

Which all means that the state has built enough new utility-scale solar to reach those peaks even with less solar energy than we had in August and September.

Those are peak outputs, of course. The total amount of solar power produced depends on the number of hours over which the solar facilities operate, and those hours are less during the short days of winter. In that important respect, that record-setting August 9 still stands proud: the state's solar facilities pumped 23,130 megawatt-hours of power into the CaISO grid, compared to 21,159 on subsequent record--setting day September 12, 19,376 on November 6, and a measly 16,386 on November 30.

Also worth keeping in mind, as always, is the fact that these records only count solar generation on the far side of the electric meter. Net metered rooftop solar, or solar panels that power parts of California not connected to CaISO's grid, are not counted in these reckonings. As of November 27, according to the California Solar Statistics website, 1,888 megawatts' worth of net metered and similar generating capacity was hooked up on the side of California's electric meters where CaISO can't see it. That means it's very likely that at least 1,000 megawatts more solar power was actually being generated and used in California last Saturday just after noon than CaISO can track. The state might actually have been generating something like 3,600-4,000 megawatts of solar power at noon Saturday.

And we can't help but point out once again that California's solar power production lags well behind relatively gloomy Germany, which recently peaked at around 24 gigawatts of solar output on July 21 at 3:00 in the local p.m. 24 gigawatts is 24,000 megawatts. That July 21 German output is a bit more than nine times California's peak on Saturday, and Germany has continued to build capacity since July.

Still, it's something to strive for: and three weeks from now when the days start getting longer in the Golden State, that'll only help.

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.

We are dedicated to providing you with articles like this one. Show your support with a tax-deductible contribution to KCET. After all, public media is meant for the public. It belongs to all of us.

Keep Reading