by Chris Clarke
Rewire | KCET.ORG
News reports are saying that the world's largest concentrating solar facility went online in California's desert at the beginning of the month. But figures from the state's grid operator suggest that solar thermal power production in California actually cratered for most of the month.
According to a piece by reporter David Danelski on the website of the Riverside Press-Enterprise, the 370-megawatt Ivanpah Solar Electric Generating System near the Mojave National Preserve went online at the beginning of January, starting to feed solar thermal power to California's grid.
Agency documents cited by Danelski do indeed reflect a startup date of December 30, 2013 for the project. But figures from the California Independent System Operator (CaISO), which operates the power grid for most of California, suggest that rather than having an immediate boost in energy entering the state's grid, production by California's concentrating solar thermal power plants actually fell nearly to nothing for most of the month.
The 377-megawatt project, designed and sponsored by BrightSource Energy and owned by BrightSource, NRG Energy, and Google, is being completed by contractor Bechtel on close to 4,000 acres of public land in the Ivanpah Valley south of Las Vegas.
But if Ivanpah has gone online, the state's figures seem not to show and increase in solar energy coming into the grid. CAISO tracks energy entering its grid from various forms of renewable energy and releases those figures in daily Renewables Watch documents. For more than a year, CaISO has been tracking photovoltaic power and solar thermal power in separate categories.
Power entering the grid from solar PV -- the same solar panels you may well have on your roof -- utterly dwarfs that coming from solar thermal plants, where steam generated by concentrated solar heat is used to turn turbines. That's because the state's operating solar thermal plants are few: there's ESolar's five-megawatt Sierra Suntower solar power tower plant outside Lancaster, and about 400 megawatts of generating capacity in less than a dozen parabolic trough facilities owned by Luz in San Bernardino County.
Those concentrating solar facilities put an average of 1,072 megawatt-hours of power into the grid each day in February 2013, to give an example of a winter day production baseline for existing plants.
CaISO doesn't break the figures down by which individual plants produce the power. But with even one of Ivanpah's three 125-megawatt power towers coming online in January, you'd expect to see an immediate jump in daily solar thermal production. Instead, January's records show that solar thermal output tanked. For some time in December 2013, the state's solar thermal output hovered around 500 megawatt-hours per day with peak daily outputs around 99 megawatts -- already significantly lower than February 2013's output.
On January 2, production jumped dramatically to 3,082 megawatt-hours, with a peak of 264 megawatts, which could be consistent with one of Ivanpah's towers firing up and putting power into the grid. But then the next day, the state's solar thermal energy production plummeted to just 40 megawatt-hours, with a peak output of just seven megawatts.
The state's solar thermal power production stayed essentially flat for almost the rest of the month, only this week approaching their December averages.
The red line shows total power production in megawatt-hours, while the blue line shows daily peak outputs in megawatts.
These figures aren't consistent with the world's largest solar thermal power plant going online. They're actually consistent with most of the state's existing solar thermal capacity going down, which happened for quite a bit last January as well. (Winter, with its shorter days and more diffuse sunlight, is a sensible time to conduct maintenance on solar thermal plants. But that's a guess on our part as to why that drop might have happened.)
ReWire has an inquiry into CaISO's public affairs office to see whether there might be some inconsistency in the figures, and they've promised to get back to us.
We also made inquiries with the California Energy Commission to see whether they might explain this apparent contradiction to us, and were referred to the January 17, compliance document cited in the Press-Enterprise. That document does include a reference to the plant's Unit 1 going online on December 30, 2013. Then again, previous compliance reports from last year have mentioned earlier online dates, which have been updated as the construction schedule slipped.
When we asked project designer BrightSource Energy's press spokesperson Jared Blanton whether he could shed any light on the issue Thursday, he replied that all questions about Ivanpah are now being handled by NRG, including the question "why is BrightSource now referring all press questions to NRG?"
NRG has not yet responded to our resulting query. Danelski reports that NRG will have a formal statement on the plant's status in February.