BIG SOLAR FROM EARTH ORBIT

Ben Bova, president emeritus of the National Space Society, is once again pitching a perennial favorite: Space-based satellite solar energy collecters in orbit beaming electricity via microwaves to enormous earth receiving stations.

The idea has enormous appeal. It’s sort of the STAR WARS of the energy sector. And if the federal government can find money to research the fantasy of “clean” coal, it ought to be able to fund space power satellites (SPS), too.

Like “clean” coal, SPS comes with lots of controversy.

There’s no doubt satellites could be positioned to collect solar energy 24/7, thereby overcoming solar energy’s earthly challenges of periodicity and intermittency. The big issue is getting the energy to the consumer. A focused microwave beam would fry anything that happened to pass through it. A widely dispersed microwave beam would require a huge field of receivers.

Still, the dream – born in the late 60s like so many other impossible dreams, some of which have been realized – lives on.

At a cost of $1 or more billion, a payback period of as much as a decade, and unproven technology, financing SPS development will be extremely difficult. Bova proposes government-guaranteed loans and contracts to high-tech private space-enterprises (examples: SpaceX, Virgin Galactic) analogous to air mail-carrying contracts given to companies in the 1920s to drive innovation in flight.

Bova: “A vigorous SPS program could provide the market that the newborn private space-launch industry needs. And remember, a rocket launcher that can put people and payloads into orbit profitably can also fly people and cargo across the Earth at hypersonic speed. Anywhere on Earth can be less than an hour's flight away. That's a market worth trillions of dollars a year…"

Bova's pitch is addressed to the next President: "...Mr. Future President, I believe that you should make it NASA's primary goal to build and operate a demonstration model SPS, sized to deliver a reasonably impressive amount of electrical power -- say, 10 to 100 megawatts -- before the end of your second term. Such a demonstration would prove that full-scale solar power satellites are achievable…”

See also NASA’s Reinventing the Solar Power Satellite

Illustration for this post are from the Space Studies Institute

SPS (click to enlarge)

Energy from where the sun never sets
Ben Bova, October 20, 2008 (Washington Post via Minneapolis Star-Tribune)

WHO
Ben Bova, president emeritus, National Space Society; Peter Glaser, inventer, solar power satellite (SPS)

WHAT
The solar power satellite (SPS) solves the problem of solar energy’s intermittency and can produce solar power-generated electricity in volumes large enough to solve all energy demand problems cost effectively.

Artist's depiction of the microwaves beamed down. (click to enlarge)

WHEN
- SPS was invented by Peter Glaser in 1968.
- Solar cells have been used in space to power craft since the 1950s.

WHERE
- SPS systems would be positioned in high earth orbits.
- Receivers would be placed in large, low population earth regions like the Southwestern U.S., Middle East and Saharan deserts.

WHY
- A single SPS could deliver 5-to-10 gigawatts of solar energy-generated electricity without interruption. California’s energy consumption: 4.4 gigawatts.
- SPS-generated electricity cost: 8-to10 cents/kilowatt-hour initially. Operating costs fall with time and economies of scale.
- SPS system in space would be 1 mile across. Technology to build the International Space Station, about the size of a football field, exists.
- Microwave beams carrying the collected solar energy to earth would be so widely dispersed as to pose no threat to anything passing through it, even birds.
- Regions where there are receivers would be energy-rich and as powerful as current oil kingdoms.
- Cost of an SPS system: $1 billion. Years to pay off: Many, maybe a decade. Payment could come through U.S.-guaranteed loans.

Artist's depiction of SPS under construction. (click to enlarge)

QUOTES
- Bova: “Mr. Future President…Look to the stars…You can use the powerful technology we've forged over a half-century of space exploration to solve one major down-to-earth problem -- and become the most popular president since John F. Kennedy in the process…”
- Bova: “Americans are a frontier people at heart. We have a frontier that begins a scant hundred miles overhead and contains more riches of energy and raw materials than the entire Earth can provide. Mr. Future President, if we use these resources wisely, we can assure prosperity and peace for the world -- and you have the opportunity to write your name in capital letters across the skies.”