Even on Short Winter Days, California is Breaking Solar Energy Records
California's grid-tied solar seems to be gearing up to ring out the old year with a bang. The state broke another record on Tuesday for the amount of solar energy flowing into the state's power grid from large solar installations, with more than 2,800 megawatts of solar electricity recorded by the state's grid operator at just before noon.
According to the California Independent System Operator (CaISO), which runs the state's grid, 2,806 megawatts of power flowed into the grid from large-scale photovoltaic power plants at 11:58 a.m. on Tuesday, along with a yet-unreported amount of power from solar thermal plants. (Solar thermal's output peaked at 109 megawatts three hours later.)
At this rate, given a bit of sunny weather, it seems likely that the total solar power flowing into CaISO's grid will top 3,000 megawatts -- that's three gigawatts -- before the end of 2013. Not bad considering the state only broke 2,000 megawatts in June.
In truth, the state's already there: CaISO's figures reflect only that solar generation that's on the utility side of the state's electric meters. According to the California Solar Statistics site, which tracks rooftop solar projects that sell power to utilities through net metering contracts, there were 1,898 megawatts of solar power generating capacity on California rooftops (and carports and other such places) as of December 4.
That means California's certain to have been generating significantly more than 3,000 megawatts of solar power Tuesday, perhaps more than 4,000 megawatts. It's just that the rooftop solar isn't visible to CaISO, so they don't track it.
Even discounting rooftop generation, breaking 2,800 megawatts a week and a half before the shortest day of the year says something about the pace at which California has been installing solar power generating capacity. And the fact that CaISO's tracked PV separately from solar thermal for the last year exposes something interesting: the astonishing growth of photovoltaic generation on either side of the state's electric meters has left other solar technologies in the dust.
That's promising for a few reasons, one of which is that the record-setting solar panels CaISO can track could be installed just as easily in urban and suburban settings as they can in remote desert wildlands. Which means they can accentuate habitat rather than replacing it.
One other interesting tidbit has to do with the amount of actual power generated during the course of the day. After all, the state doesn't use power just for a moment; it uses power 24/7, and so the crucial measure of renewable energy production is megawatt-hours, not just megawatts. All told on Tuesday, the PV panels CaISO tracks generated 16,916 megawatt-hours to the grid. The record so far for 2013 -- and thus for the state's entire history -- was set September 27, when PV tracked by CaISO generated 21,015 megawatt-hours.
What's impressive about Tuesday's generation running almost 4,100 megawatt-hours behind September 27's? This: there were 12 hours between sunrise and sunset on that September day, and less than 10 hours on Tuesday. Crunch the numbers and it turns out that Tuesday's solar energy production per hour of daylight was almost exactly equal to that of September 27: less than a single percent lower. That's despite the fact that the sun is much lower in the sky in December than it is in September, and the amount of solar energy per square foot significantly lower.
Which means that the state's PV generating capacity has grown enough since September to erase the disadvantage of the weaker winter sun, at least in terms of power per hour of sunlight. After the solstice on December 21, when the sun starts climbing higher in the California sky again, we should start seeing some serious gains in PV power generation.
When it comes to California solar, in other words, 2014 promises to outshine 2013 by a considerable margin.