Topping one gigawatt in solar power production on a hot August day was a milestone that both shows how far California has come with solar power and how far it has to go.

The California Independent System Operator (CAISO), which runs the state’s grid, said the state cracked one gigawatt for the first time and hit a utility-scale solar generation peak of 1,003 megawatts on Tuesday, Aug. 14.

First time over the one gigawatt mark (image via California ISO)

That record of 1,003 megawatts has since been broken several times, with the latest high-water (high-sunlight?) mark coming on Friday, Aug. 31, at 1,076 megawatts. CAISO says one megawatt can meet the instantaneous demand of at least 750 homes, so in these instances, solar was powering more than 750,000 California homes.

Peak output is just a snapshot in time, however, and solar’s climb over the one-gigawatt barrier invites a closer look at how solar fits into the Golden State’s energy picture. Let’s go back to Aug. 14 to get a sense of that.

Solar generating stations began to trickle power onto the grid around 6 a.m. Production climbed throughout the morning, peaking around 1 p.m. It began to slide very slowly in the next couple hours, was off 10 percent by 3 p.m., and then took a steeper drop. By 6 p.m. it was down to half of what it had been six hours earlier. By 10 p.m., the last solar-inspired electrons had moved.

It all added up to 8,843 megawatt-hours of electricity flowing onto the grid, out of 869,260 megawatt-hours of electricity used by Californians that day. That means wholesale solar accounted for almost exactly one percent of the day’s electricity demand. (Wind power, meanwhile, met 3.7 percent of the day’s electricity demand.)

Renewables production, Aug. 14, 2012 (image via California ISO)

This makes the point, if it wasn’t already obvious, that solar has a great distance to travel before it can be seen as a big contributor in meeting California’s electricity needs. But it’s hardly enough to dismiss solar, for a couple of reasons.

First, go back to Aug. 14, 2010, and on that day, you’ll find solar’s contribution to the grid to be less than three-fifths what it was on Aug. 14, 2012. From 0.6 percent to 1 percent of total generation might sound small, but it’s a big jump in just two years, and with several utility-scale plants in development -- giant ones like Solar Ranch One in the Antelope Valley and Ivanpah in the Mojave Desert, and many smaller ones, too -- there’s no reason to think growth won't continue at a fast or even accelerating pace.

Plus, remember, we’re talking only about wholesale solar here. California also has more than 1 gigawatt of solar capacity behind meters -- on the roofs of businesses and homes all over the state -- that isn’t included in the California ISO totals. As Vote Solar noted, “When you add the 1.2 gigawatt and counting of customer-owned solar generation that serves onsite load, the total more than doubles.” And that total is growing fast, too.


Editor's note: This article is reposted in its original form from EarthTechling. Author credit goes to Pete Danko.