California Approves Space-Based Solar Plant

Posted by Charlotte LoBuono on December 6, 2009 at 10:44 am

Illustration of the power plant beaming former solar energy to Earth. (image: consumerenergyreport.com)

The Green, Inc. blog of the New York Times reported on Thursday that California regulators approved a utility contract for the first space-based solar power plant in the U.S. The 200-megawatt orbiting solar farm would convert solar energy collected in space into radio frequency waves, which would be beamed to a ground station near Fresno, in California’s central valley. These radio waves would then be transformed into electricity to be fed into the power grid.

Global leaders have recently become more serious about breaking the world’s addiction to fossil fuels. To that end, the viability of more unusual technologies, including space-based solar power, are being evaluated. For example, Japan announced in September that it also plans to launch solar power satellites into space.

“At the conceptual level, the advantages of space-based systems are significant,” Michael Peevey, president of the California Public Utilities Commission, said during a hearing on Thursday. He continued; “while there’s no doubt this project has many hurdles to overcome, both regulatory and technological, it’s hard to argue with the audacity of the project.”

Space-based solar power neatly circumvents one of the biggest problems with ground-based solar power: cloud cover. In addition, because space is obviously BIG, many square miles of solar collectors could be put into orbit, and not take up space here on Earth. Each satellite could beam power to multiple receivers, allowing energy to be sent to where it is needed.

However, space-based solar power is very costly and subject to damage from space debris and meteors, and the power transmission beam may not stay locked on its ground-based receiver. In addition to posing an engineering challenge, this last issue could prove dangerous. The satellite would beam energy to Earth using microwaves, and a concentrated 1 gigawatt beam can vaporize 500 kilograms of water per second. That is the equivalent of vaporizing 5 or 6 adults.

Southern California startup Solaren will launch components of the solar farm into orbit and sell the electricity generated to Northern California largest utility, Pacific Gas and Electric, under a 15-year contract. Solaren plans to deploy a free-floating inflatable Mylar mirror one kilometer in diameter. As described in the company’s patent, this mirror will collect and concentrate solar rays on a smaller mirror, which in turn will focus the sunlight on photovoltaic modules.

Solaren CEO Gary Spirnak told grist.com in April that in order to make a space-based solar farm economically viable, it is important to reduce the number of rocket launches by reducing the weight of the system. Spirnak also acknowledged that launching a solar power plant into space would cost several billion dollars more that a terrestrial photovoltaic farm generating the same amount of electricity.

The amount that P.G. & E. will pay Solaren for the electricity produced by the solar station was not disclosed. Also, regulators said on Thursday that the project would not meet the utility’s renewable energy mandates unless certain milestones were reached.

In addition to space-based solar, other technologies being studied are advanced car batteries, storage of energy created by wind and solar power, carbon capture, and next generation biofuels.