photo: Todd Woody
I wrote this story for Grist, where it first appeared.
While efforts to pass federal climate change legislation have stalled and a fight rages in California to overturn its global warming law at the ballot box, Golden State regulators have been licensing massive desert solar power plant projects at a breakneck pace in recent weeks.
On Wednesday, for instance, the California Energy Commissioned approved two solar projects that would generate nearly 1,000 megawatts of electricity, the 250-megawatt Genesis Solar Energy Project and the 709-megawatt Imperial Valley Solar Project.
Since Aug. 25, the energy commission has licensed six solar thermal power plants that would cover some 39 square miles of desert land and generate 2,829 megawatts. That’s nearly six times as much solar capacity that was installed in the United States last year, mostly from rooftop solar panels.
“Consider how important it is that California move aggressively toward renewables and how important these pioneering projects are,” said Jeffrey Byron, a member of the California Energy Commission, said at a hearing Wednesday.
Regulators and developers are racing to put shovels to ground before the end of the year when federal incentives for large renewable energy projects expire, which could threaten the financial viability of some of the solar projects.
The Genesis project, to be built by Florida-based energy giant NextEra Energy Resources (formerly called FPL), will build long rows of parabolic troughs in the Riverside County desert that will focus sun on liquid-filled tubes suspended over the mirrors to create steam that will drive an electricity-generating turbine. It’s an older solar technology that was first deployed in the 1980s in California.
Tessera Solar’s Imperial Valley project, on the other hand, will be the first big test of Stirling dish technology. Resembling a giant mirrored satellite receiver, the 38-foot-high, 40-foot-wide, solar dish focuses the sun’s rays on a Stirling engine, heating hydrogen gas to drive pistons that generate 25-kilowatts of electricity. Some 29,000 of Tessera’s Suncatchers will be installed on more 6,400 acres of desert land near the Mexican border about 100 miles east of San Diego.
Meanwhile, California Gov. Arnold Schwarzenegger this week signed into law what is thought to be the nation’s first energy storage legislation. The bill, AB 2514 could result in regulations requiring the state’s utilities to store a certain percentage of electricity generated in energy storage systems such as batteries, compressed air or flywheels.
Energy storage is considered crucial for the mass deployment of solar power plants, wind farms and other sources of intermittent renewable energy, as well to build out the smart grid.
Green Wombat 
First off it is good to see these projects get started. I would also like to see a bonus paid for plants that will use energy storage so we can advance that technology too.
I hope it works out for the Stirling Dishes. One advantage I believe they will have over conventional power plants is they are able to adjust to the seasonal north-south movement of the sun. The trough style plants are not able to do this and they lose some efficiency because of it. The tower style power plants should be able to do this also.
Now first off I am far from an expert on the Stirling Dish but I think it will have some problems competing with conventional solar thermal. First off its efficiency claims are BS. It may do very well for the amount of sun hitting the dish but will require more land than convention solar for the same amount of power, so that claim is just smoke and mirrors. A few years ago they were trying to get a company I worked for to go in with them on projects. This company is well established in solar and other renewable energy. They basically considered the Dishes to be a joke. They felt that they were drastically underestimating the maintenance and manpower needed to run these things. I know they have recently redesigned the dishes to use less parts but I am skeptical on just how well these things will work in the harsh desert climate. It is one thing to operate a few hand built and maintained units. It is quite another to operate 29,000, mass produced units, on ten square miles of desert.
Another claim the dishes use is decreased water use but with most of the conventional solar thermal plants using dry cooling that should be a very small advantage for the dishes. In a steam power plant very little water is actually used to make steam as it is a closed system. Most of the water use will be used to clean the mirrors. This is something that the dishes will have to do too, so there should be very little advantage and honestly I am not really sure how easy it will be to clean the dishes. They look to me like they will be difficult. The trough style systems are fairly smooth and together in one place. They usually get one good hand cleaning a year and then they are easy to wash off with high pressure sprayers on a water truck the rest of the time.
Don’t forget to mention thermal energy storage, Todd. The Southern California Public Power Authority embarked on a program earlier this year to install distributed thermal energy storage units throughout its member utility service territories over the next few years. They’ll use these devices to cool buildings during peak hours from ice made at night.
The thermal energy storage units can absorb loads from renewables, particularly night time wind. It’s worth noting that the program doesn’t involve subsidies. SCPPA buys the units and installs them on commercial buildings free of charge to the ratepayer.