Japan plans to harvest sun in space - Bold plan for solar energy

Canberra Times
Monday 9/11/2009 Page: 11

It may sound like a sci-fi vision, but Japan's space agency is dead serious: by 2030, it wants to collect solar energy in space and zap it down to Earth, using laser beams or microwaves. The Japanese Government has just picked a group of companies and team of researchers tasked with turning the ambitious, multibillion dollar dream of unlimited clean energy into reality in coming decades. With few energy resources of its own and heavily reliant on oil imports, Japan has long been a leader in solar and other renewable energies. It set ambitious greenhouse gas reduction targets this year.

But Japan's boldest plan to date is the Space Solar Power System, in which arrays of photovoltaic dishes several square kilometres in size would hover in geostationary orbit outside the Earth's atmosphere. Researchers at Mitsubishi Heavy Industries, one of the project participants, wrote in a report, "Since solar energy is a clean and inexhaustible energy source, we believe that this system will be able to help solve the problems of energy shortage and global warming. The sun's rays abound in space."

The solar cells would capture the solar energy, which is at least five times stronger in space than on Earth, and beam it to the ground through clusters of lasers or microwaves. These would be collected by gigantic parabolic antennae, likely to be in restricted areas at sea or on darn reservoirs, a spokesman at the Japan Aerospace Exploration Agency, Tadashige Takiya, said. The researchers are targeting a 1-GW system, equivalent to a medium-sized atomic power plant, that would produce electricity at 8 yen (AlOc) a kW-hour; six times cheaper than its current cost in Japan.

The challenge - including transporting the components to space - may appear gigantic, but Japan has pursued the project since 1998, with about 130 researchers studying it under the agency's oversight. Japan's Economy and Trade Ministry and the Science Ministry took another step toward making the project a reality last month, by selecting several Japanese high-tech giants as participants in the project. The consortium, named the Institute for Unmanned Space Experiment Free Flyer, also includes Mitsubishi Electric, NEC, Fujitsu and Sharp. The project's road map outlined several steps that would need to be taken before a full-blown launch in 2030.

One of the agency's researchers heading the project, Tatsuhito Fujita, said that within several years, "a satellite designed to test the transmission by microwave should be put into low orbit with a Japanese rocket". The next step, expected in about 2020, would be to launch and test a large flexible photovoltaic structure with 10-MW power capacity, to be followed by a 250-MW prototype. This will help evaluate the project's financial viability, officials say.

The final aim is to produce electricity cheap enough to compete with other alternative energy sources. The space agency says the transmission technology will be safe but concedes it will need to convince the public, which may harbour images of laser beams shooting down from the sky, roasting birds or slicing tip aircraft in mid-air. A 2004 agency survey found the words "laser" and "microwave" caused the most concern among the 1000 people questioned.