Cool Earth Solar: News Archive

Back in January 2007, the Bush administration was urging the world's scientists to explore the possibility of deploying giant space mirrors that would block sunlight from reaching the Earth and hence reduce global warming. (Really.) The thought here was that this might work as a decent last-ditch save-the-planet gambit if we couldn't get our collective acts together and reduce greenhouse-gas emissions quickly enough. One of the options under consideration, as it happened, involved "thousands of tiny, shiny balloons." Now, I confess, there may have been some snickering from the TNR peanut gallery at the time, but maybe I was just underestimating the power of shiny balloons, at least judging by this Fortune report about a startup firm that's developing a balloon-based solar plant:

It sounds like something out of one of those do-it-your-self magazines: Stitch together two buck’s worth of thin-film plastic--the stuff potato chip bags are made of--stick in a photovoltaic cell, inflate with air and, voilà, you’ve got yourself a "solar balloon" that will generate a kilowatt of electricity. String together 10,000 balloons and you’ve got a solar power plant that can power a town.

California startup Cool Earth Solar believes this high-low tech approach is what will make its solar power plants competitive with fossil fuels. … Here’s the ingenious part of the technology, developed by scientists at Caltech: Instead of using expensive optics to concentrate sunlight on the solar cell, Cool Earth manipulates the air pressure inside the balloon to change the shape of the mirrored surface so that it focuses the maximum amount of sunlight on the solar cell, boosting electricity generation 300 to 400 times.

The company, founded in 2007, has raised $21 million so far. It plans to build solar power stations in the 10-megawatt to 30-megawatt range. Two to six balloons will be suspended on wood poles and anchored with cables about 10 feet off the ground. That means the earth won’t have to be graded, reducing the environmental impact of Cool Earth’s power plants - a growing issue given that most solar thermal power stations will be built in the desert, home to a plethora of protected wildlife. The relatively compact size of Cool Earth’s power stations also means they can be located close to existing transmission lines.

That last sentence is key. As The New York Times' Matthew Wald relays today, the North American Electric Reliability Corporation just released a report arguing that large-scale attempts to ramp up renewable-power production will put an unbearable strain on the current U.S. grid—in part because extending power lines out to remote wind and solar farms will "impose new demands on a transmission system that was never designed for large power transfers over extremely long distances." In fact, the report suggests, there's little hope of any major cuts in CO2 emissions unless we tackle these transmission issues. (OK, that's overstating things—there are plenty of efficiency improvements homes and businesses can make without waiting for grid improvements—but I see what they're driving at.)

So balloon farms might help, but the clearcut solution would be—and I'm getting predictable about this, aren't I?—to use some of the economic stimulus money to modernize the national grid. This is partly a question of sequencing: Congress would ideally start making major grid investments now, in addition to passing some sort of cap-and-trade regime for CO2 emissions. Any economy-wide cap will take a few years to get up and running—under Lieberman-Warner, for instance, the cap-and-trade wouldn't have started working until 2012—so, if all goes well, we'll have a better grid infrastructure in place by the time the cap starts ratcheting on down and utilities start investing heavily in renewables.

The other point the NAERC report makes is that a better grid will likely prove necessary no matter what low-carbon technologies emerge in the future—it's not just wind and solar. Even utilities that simply switch from coal to natural gas, or utilities that try to capture and bury CO2 from coal plants, will encounter reliability problems. A smart grid that allows better demand-side management—say, by giving utilities the ability to shut off certain non-vital activities, like swimming-pool pumps, during periods of peak use—would allow the country to transition away from dirty coal without having to suffer rolling blackouts and so forth.

--Bradford Plumer

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