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Space-based solar power still holds promise, but faces huge barriers beyond simply technology. (credit: © Mafic Studios Inc.)

An electrifying conference?


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It was the best of conferences, it was the worst of conferences. It was the SPACE Canada 2009 International Forum on Solar Energy from Space, held at the Ontario Science Centre September 8–10. Never have the prospects for space-based solar power (SBSP) looked better technically—or more challenging economically and politically.

The tempting promise of gigawatts of electricity, harvested from kilometer-wide arrays of solar cells in geosynchronous orbit and beamed by microwave or laser to receiving stations on Earth, was too ambitious when first proposed by Peter Glaser in 1968. The technological challenges and high costs stifled most government and industry interest.

A wide range of challenges confronts SBSP. Perhaps the easiest to solve are the technological.

Interest did not totally die. Occasional overviews reached the same conclusions as early studies: SBSP was theoretically attractive but impractical. That changed with a very positive 2007 study by the Defense Department’s National Space Security Office, which sparked interest and more detailed studies (for the reports, go here). The greater interest was aided by easier communications, which enabled websites like Space-Based Solar Power (sponsored by the Space Frontier Foundation) and new organizations such as SPACE (Solar Power Alternative for Clean Energy) Canada, founded this year by lawyer George Dietrich.

Indeed, SPACE Canada and the National Space Society sponsored the workshop for an ongoing International Academy of Astronautics report on the subject, planned for completion early in 2010. The workshop discussed the known universe of issues needed for SBSP to evolve from promising idea to commercial reality.

A wide range of challenges confronts SBSP. Perhaps the easiest to solve are the technological. SBSP technology has matured greatly since first studied in the 1970s. Advances in solar cells, wireless power transmission, robotics, construction techniques, and other areas have made SBSP much more attractive technically. As the workshop made abundantly clear, a wide range of options exist for most systems and components.

Transmitting power to Earth, for example, could be done by microwave or laser or a combination. In the latter, an infrared laser on the station would transmit power to a balloon at 70,000 feet (21,000 meters), to avoid having the lower atmosphere absorb the laser’s power; the balloon would then retransmit the energy by microwave to a rectenna on the ground. The combination would send smaller amounts of power to more substations, just as a modern communications satellite uses several spot beams to numerous ground stations.

Harder to solve were issues ranging from overcoming the giggle factor to coordinating operations with utilities and, most important, creating a viable economic case for SBSP. The popular axiom “build a better mousetrap and the world will beat a path to your door” is wrong. Technologies need to be promoted and SBSP proponents need to become more effective advocates, publicists, and promoters.

As a panel of reporters made painfully clear, SBSP failed the media interest test. Convincing editors and then readers that SBSP is a worthwhile story, that SBSP is a better source of baseload electricity than competing proposals, and that SBSP will help and not harm people, would be an enormous but necessary task.

Even more painfully, SBSP also failed the investment test. Doable technology is worthless without feasible finances. Attracting investors and patrons will demand not only presenting viable economic plans, but also presenting SBSP in their language and concepts. Similarly, utilities must become involved now, especially for planning how to integrate ground substations with space-based power, as the ultimate customer.

Actually transmitting small but meaningful amounts of power from space—tens or hundreds of kilowatts from LEO instead of hundreds of megawatts from GEO—would provide a dramatic proof of possibility.

One consensus was the need for key demonstrations to demonstrate the viability of SBSP concepts and attract interest from possible funders, investors, and customers. Proving technical feasibility would not be enough. Demonstrations should also generate near-term financial return. Applying microwave power transmission to terrestrial applications to replace conventional transmission lines would demonstrate the feasibility of wireless power transmission while generating income and attention.

Actually transmitting small but meaningful amounts of power from space—tens or hundreds of kilowatts from LEO instead of hundreds of megawatts from GEO—would provide a dramatic proof of possibility, especially if the recipients were developing countries that sorely needed the electricity. Funding these early projects will be expensive and the traditional financial patron of aerospace technologies, the military, might play a major role, especially if SBSP could provide power to bases.

The sessions confirmed that the last decades have produced impressive technological advances in every area except launch costs. Launch costs could doom SBSP to remaining only on paper. At current costs of $10,000 a pound, placing the 3,000 tons needed for a one-gigawatt station into GEO would cost $60 billion, three times NASA’s current annual budget. At $1,000 a pound, launching would demand $6 billion, the cost of a new nuclear plant. At $100 a pound, $600 million would be needed, a large but not implausible amount.

Nonetheless, here too optimism abounded. Presentations on low-cost launch options ranged from operations-optimized chemical rockets to radical ground-based technologies like magnetic levitation and beamed energy propulsion. All suffered from the same problem: developing new systems would cost billions of dollars, investments that would not flow unless there was much greater demand than currently ecxists. SBSP would provide the demand that would justify the new investment. The creation of a low-cost launch system could in turn dramatically expand access to space exploration and exploitation.

Although American speakers dominated, Japanese participants from the University of Kobe had the most impressive demonstration, using a pilot beam so a microwave transmitter could accurately track and transmit to a moving target, and descriptions of their government’s expanding program for SBSP. Other international aspects of SBSP included the need to establish standards, work with the International Telecommunication Union (ITU) for frequency allocations for microwave transmission, create (and conform to) international space law, jointly develop SBSP, avoid interfering with radio astronomy, and, most importantly, serve as a market.

In the decades since it was first proposed, SBSP’s virtues have only increased due to growing concern about providing environmentally sound and economical baseload electricity. Over the next decades, utilities will invest trillions of dollars in building hundreds of gigawatts of capacity to provide electricity to new markets, primarily in the developing world, as well as to replace existing power plants worldwide.

Indicative of the low visibility of SBSP and lack of research funding, most of the participants were over 50. Almost completely missing was the generation of postgraduates and young researchers who came of age in the 1990s and 2000s.

Fossil fuels such as coal increase global warming, nuclear power is very capital-intensive and still lacks a safe way to dispose of waste, and renewable fuels have not demonstrated the necessary scale, capability, or economics. There is no NIMBY (not in my backyard) opposition to SBSP because the backyard is 36,000 kilometers away in geosynchronous orbit (although placing the receiving rectennas may be a point of contention). Compared with terrestrial solar and wind power, SBSP is independent of local weather conditions and can produce power 24 hours a day. Indeed, space solar power complements, not compete with terrestrial solar power.

Attractive as SBSP is theoretically, becoming reality will not be easy. Indicative of the low visibility of SBSP and lack of research funding, most of the participants were over 50. Many had worked on SBSP for decades. Almost completely missing was the generation of postgraduates and young researchers who came of age in the 1990s and 2000s. SBSP needs to attract new people who will find this professionally rewarding as well as technically challenging. Missing also were potential allies, like environmentalists, as well as potential critics. That is, SBSP is still too small to attract much interest beyond its advocates.

Encouragingly, the meeting attracted startups like the Powersat Corporation and Planetary Power, Inc. as well as energy entrepreneur Wael Almazeedi of the FATE (Free Access To Energy) Consortium. This expansion of the SBSP community to people dealing in electricity was probably as important as the technical discussions.

Next spring the International Academy of Astronautics will release its report, which will provide a blueprint for the technological realization of SBSP. While that will be an impressive accomplishment, this workshop showed that SBSP faces equally demanding challenges of reducing launch costs and capturing the attention and resources of investors, utilities, and other key constituencies. To its advocates, the benefits of essentially pollution-free, unlimited electric power are obvious; others need to be informed and convinced.


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