A July report by the National Renewable Energy Laboratory (NREL) puts California in the lead among U.S. states when it comes to how much power we could be generating on our rooftops and in our cities.
The report, "U.S. Renewable Energy Technical Potentials: A GIS-Based Analysis," assesses California's rooftop solar generation potential at a stunning 76 gigawatts of capacity, almost twice the state's typical power demand on a peak day, and 16 gigawatts more than the state in the number two slot, Texas.
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If built out, the report says, California could generate 106 terawatt-hours of power each year on its rooftops, an eighth of the U.S.'s total rooftop solar potential output. A terawatt-hour is equal to a million kilowatt-hours, and 106 terawatt-hours of power would be sufficient to power the entire state of California for five months.
California comes in second to Texas, according to NREL, in potential for development of utility-scale solar photovoltaics in urban settings, which the NREL defines as large-scale solar inside urban boundaries. The Lone Star State could potentially build 154 gigawatts of generating capacity, compared to California's potential 111 gigawatts. Not that we should feel like slouches in the urban utility-scale realm: that 111 gigawatts of capacity would generate 246 terawatt-hours of power, more than 95% of the state's current consumption.
We don't come out as well in the rural utility-scale PV category, lagging in total output potential behind such solar paradises as South Dakota and Kansas. And we come in fifth in potential for concentrating solar, behind Texas, New Mexico, Arizona, and Colorado.
As regards that power consumption, incidentally, that's another area where California comes in second to Texas according to NREL. California consumes 258,525 gigawatt-hours of power each year, and Texas consumes almost 100,000 gigawatt-hours more than that at 358,458.
Of course, without energy storage solar alone can't power California: the sun goes down every day and solar power facilities stop producing power. But the report is an indication that photovoltaic development in the built environment is the solar arena in which California offers the most potential, and suggests that we might adopt that route as a state priority.