Scientific American reports:

When inventor Charles Fritts created the first crude solar photovoltaic cells in the 1880s, one might have thought the achievement would rapidly revolutionize global electricity production. There is, after all, no power source cheaper, cleaner and more ubiquitous than sunlight. Yet despite enormous (and ongoing) technical advances making solar power ever more capable and affordable, some 140 years on it still supplies less than 5 percent of the world’s electricity. For all its benefits, solar power does have drawbacks that can limit its use—chief among them the fact that half the planet’s surface is in darkness at any given time.

In 1968 U.S. aerospace engineer Peter Glaser detailed a potential solution to these problems that was not only “outside the box” but entirely outside Earth’s atmosphere. Instead of building gigantic solar farms across vast, ecologically vulnerable tracts of land, Glaser proposed to loft the photovoltaics into orbit on fleets of solar power satellites. In orbit—unattenuated by clouds and freed from planetary cycles of day and night—sunlight could be harvested with optimum efficiency, then beamed as microwaves to ground-based “rectifying antennas” (rectennas). Back on Earth, the microwaves would be converted to electricity and channeled into power grids across the globe.

At the time and for decades afterward, however, the cost of space launches was too high and the performance of photovoltaics was too low to make Glaser’s bright idea a reality. But now technological advances, paired with the growing need for clean energy, are reinvigorating the concept of space-based solar power (SBSP), with pilot projects emerging in the U.S., China, Europe and Japan. As a new wave of research begins, the question lingers: Will SBSP ever be ready for its moment in the sun? [Continue reading…]