3. RENEWABLES: Solar energy beamed from space is getting a second look (ClimateWire, 09/15/2008)

Christa Marshall, ClimateWire reporter

Scientists are trying to take gigantic solar panels boldly where they never have gone before: outer space, to power electricity on Earth.

The notion is a 40-year-old idea often slammed as far-fetched fantasy, but one that is getting renewed attention because of its potential to supply the energy needs of humans a hundred times over without exacerbating global warming.

And followers now have proof for the first time that solar-powered microwaves -- the mechanism that would carry energy from the sun back to Earth -- can travel the distance to make the concept work in theory. In a recent demonstration in Hawaii, a team led by former NASA physicist John Mankins transmitted a solar-generated energy beam 90 miles between two islands -- more than the distance from the planet's surface to outer space.

"The potential for space solar power is so large that if it works out it would transform the American economy to a far greater extent then the auto industry did," said Mark Hopkins, senior vice president of the National Space Society, who appeared at a press conference with Mankins Friday in Washington, D.C. The scientists' work is the focus of a new television program from Discovery Communications, which funded the roughly $1 million project.

The demonstration transmitted microwaves 100 times farther than a 1970s-era test performed by NASA in California's Mojave Desert. Although it sent power horizontally across land rather than vertically from space, Mankins said it's just a matter of scaling things up. Doing so, he said, would eliminate one of the problems of land-based solar: The sun always shines in space, so there's no need for storage.

But don't expect Americans to flip on their light switches next year with electricity from satellites orbiting the Earth. As optimistic as he is, even Mankins acknowledged that there are many challenges to overcome before a commercial system can become operational.

And the test itself transmitted a tiny amount of power -- only 20 watts, less than the power used by the average incandescent light bulb. Mankins said he restricted the test to 20 watts to comply with FAA requests.

High costs and complexities must be overcome

The most obvious obstacle to space-based power generation is cost, despite advances in solar panels and wireless transmission since 1981, when the federal government estimated that space solar power would be a $3 trillion endeavor. NASA last investigated the technology as part of its "Fresh Look" study in 1997 and also found expense would be a chief barrier.

With countries struggling just to maintain the International Space Station, it's difficult to imagine how complex satellites could be rocketed into space cheaply, much less maintained, several analysts said. To truly bump up the electricity supply and affect climate change, there would need to be a virtual solid stream of massive solar panels and mirrors circling the planet like a moat, they said.

"My guess is, we would need to reduce the cost by a factor of a hundred, compared to single digits for land-based solar systems," said Roger Angel, Director of the Steward Observatory Mirror Laboratory at the University of Arizona.

According to Mankins, the answer lies in changing how space equipment is built, so that manufacturers produce hundreds of small components rather than one big apparatus. He compared the current way of doing things to making a Swiss watch the size of an aircraft carrier. Instead, he said, the process should follow the pattern of the computer revolution -- when big, clunky servers the size of rooms were replaced with easy-to-manufacture and lightweight machines connected to the Internet.

Worries linger about the danger of microwaves

A new technology unveiled last year called a modular symmetrical concentrator, which would tie large mirrors to a photovoltaic panel before shooting their power back to land, would be easier to assemble than past alternatives, he said.

"Everything has to go to plug-in and play," he said.

There are questions about the safety of the microwaves, though, a point considered by the National Research Council in a 2001 report. The issue was not tested by Mankins and his team in Hawaii.

"The microwaves might be harmless, but we don't know," said Molly Macauley, a senior fellow and director of academic programs at Resources for the Future. Even if the waves prove benign -- which Mankins said current evidence indicates -- the perception of a potential danger could be a deal-killer for the public, she said.

Mankins acknowledged that "thermal warming" could occur near the terrestrial landing spots of the solar beams, prompting wildlife to migrate.

Other details, such as whether the microwaves would interfere with airplane radar and force the Federal Aviation Administration to restrict airspace, are ongoing unknowns.

The military sees it as a 'game changer'

Even so, the U.S. military is not taking space-based solar power lightly, particularly as it must transport energy-making fuels to bases in war zones at a gargantuan price. Standing in the back of the National Press Club room where Mankins spoke stood Lt. Col. Paul Damphousse of the Pentagon's National Security Space Office.

"We think this is very important," he said. "Our energy needs are huge, and this may be one way to get it."

Discussions about a military-NASA demonstration project of solar wireless transmission on the International Space Station are far enough along that the project might be feasible within a few years, he said. The Defense Department also is funding some research, he said.

Last year, the National Security Space Office released a report concluding that energy beamed from space "has the potential to be a disruptive game changer on the battlefield" that could produce electricity on demand for combat units and reduce danger to land-based vehicles carrying fuel.

To help ensure that American defenses remain "relevant" over the 21st century and protected from energy scarcity, the office recommended that the federal government step up its research funding, since the U.S. aerospace industry is not currently equipped to build a space solar infrastructure.

"Considering the development timescales that are involved and the exponential growth of population and resource pressures within that same strategic period, it is imperative that this work for 'drilling up' vs. drilling down for energy security begins immediately," the Defense Department report said.

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