BrightSource Energy has two new mega solar thermal projects in “advanced development” in California, according to its recent filing with the SEC. Rio Mesa Solar is planned on a 6,000 acre site, and Hidden Hills Ranch in Riverside County is a solar thermal project on 10,000 acres with a rated capacity of 500 MW.
Rio Mesa Solar is still in development, but the Hidden Hills project has advanced to the point where it is included in the CEC tracking report that was just updated this month.
The CEC is tracking the progress of all the renewable energy projects that together will add up to 33% of California’s electricity use projected for 2020. Utilities in California must get 33% of their electricity from renewable energy sources, which for the purposes of this rule, exclude nuclear power and hydro electricity.
The two largest solar thermal projects on the CEC tracking count are two in Riverside County from BrightSource – the 500 MW Hidden Hills solar thermal project, and a 750 MW solar thermal project in Palo Verde, Riverside.
The next largest projects are Solar Millenium’s Palen project at 484 MW, Abengoa’s Mojave Solar 1 at 250 MW, and the Rice Solar project from Solar Reserve (that includes night time storage) at 150 MW – with the remainder all small power stations of 50 MW or less.
For a capacity comparison, a typical natural gas plant in California is about 150-250 MW, so BrightSource is proposing solar thermal projects with twice to three times the capacity of California’s natural gas plants. (The state currently gets about 45% of its electricity from natural gas, but that is changing now with the beginnings of renewable energy, following the new mandates.)
When a solar plant is rated for a capacity of 500 MW, that does not mean that it makes some percent less than 500 MW “because the sun does not shine at night” – as some argue in comment threads on websites. The rated capacity takes into account that with solar – production takes place only from sun up to sun down, and the project is sized to be powerful enough so that the desired amount of energy is produced within the annual average number of sunny daylight hours predicted for a particular site.