FYI,

"Space-Based Solar Power Beams Become Next Energy Frontier"
Popular Mechanics
http://www.popularmechanics.com/science/air_space/4230315.html

: They're officially all the rage in the Pentagon and the private
: space industry: orbiting satellites that send solar power back down
: to earth to fight global warming—and turn a profit.

: The idea of using satellites to beam solar power down from space is
: nothing new—the Department of Energy first studied it in the 1970s,
: and NASA took another look in the '90s. The stumbling block has
: been less the engineering challenge than the cost.

: A Pentagon report released in October could mean the stars are
: finally aligning for space-based solar power, or SBSP. According to
: the report, SBSP is becoming more feasible, and eventually could
: help head off crises such as climate change and wars over
: diminishing energy supplies. "The challenge is one of perception,"
: says John Mankins, president of the Space Power Association and the
: leader of NASA's mid-1990s SBSP study. "There are people in senior
: leadership positions who believe everything in space has to cost
: trillions."

: The new report imagines a market-based approach. Eventually, SBSP
: may become enormously profitable—and the Pentagon hopes it will
: lure the growing private space industry. The government would fund
: launches to place initial arrays in orbit by 2016, with private
: firms taking over operations from there. This plan could limit
: government costs to about $10 billion.

: As envisioned, massive orbiting solar arrays, situated to remain in
: sunlight nearly continuously, will beam multiple megawatts of
: energy to Earth via microwave beams. The energy will be transmitted
: to mesh receivers placed over open farmland and in strategic remote
: locations, then fed into the nation's electrical grid. The goal: To
: provide 10 percent of the United States' base-load power supply by
: 2050.

: Ultimately, the report estimates, a single kilometer-wide array
: could collect enough power in one year to rival the energy locked
: in the world's oil reserves.

: While most of the technology required for SBSP already exists,
: questions such as potential environmental impacts will take years
: to work out. "For some time, solar panels on Earth are going to be
: much cheaper," says Robert McConnell, a senior project leader at
: the National Renewable Energy Laboratory in Colorado. "This is a
: very long-range activity."

Mark Reiff