Next100 - A Dialogue on the Next Century of Energy

Apr 13 2009

Space Solar Power: The Next Frontier?

As part of PG&E's commitment to providing more renewable energy to its customers, the utility has supported a wide range of technologies, including wind, geothermal, biomass, wave and tidal, and at least a half dozen types of solar thermal and photovoltaic power.

Now PG&E is extending that approach to tap renewable energy at an entirely new level: solar power in space.

PG&E is seeking approval from state regulators for a power purchase agreement with Solaren Corp., a Southern California company that has contracted to deliver 200 megawatts of clean, renewable power over a 15 year period.

Solaren says it plans to generate the power using solar panels in earth orbit, then convert it to radio frequency energy for transmission to a receiving station in Fresno County. From there, the energy will be converted to electricity and fed into PG&E's power grid. (See interview with Solaren CEO Gary Spirnak.)

Why would anyone choose so challenging a locale to generate electricity? For one, the solar energy available in space is eight-to-ten times greater than on earth. There's no atmospheric or cloud interference, no loss of sun at night, and no seasons. That means space solar can be a baseload resource, not an intermittent source of power.

In addition, real estate in space is still free (if hard to reach). Solaren needs to acquire land only for an energy receiving station. It can locate the station near existing transmission lines, greatly reducing delays that face some renewable power projects sited far from existing facilities.

While the concept of space solar power makes sense, making it all work at an affordable cost is a major challenge, which Solaren says it can solve.

Solaren's team includes satellite engineers and scientists, primarily from the U.S. Air Force and Hughes Aircraft Company, with decades of experience in the space industry. Its CEO, Gary Spirnak, was a spacecraft project engineer in the U.S. Air Force and director of advanced digital applications at Boeing Satellite Systems, among other positions.

They also have a long history of research to draw upon. The U.S. Department of Energy and NASA began seriously studying the concept of solar power satellites in the 1970s, followed by a major "fresh look" in the Clinton administration.

In 1997, John C. Mankins, manager of NASA's Advanced Projects Office, wrote:

Based on the recently-completed "fresh look" study, space solar power concepts may be ready to reenter the discussion. Certainly, solar power satellites should no longer be envisioned as requiring unimaginably large initial investments in fixed infrastructure before the emplacement of productive power plants can begin. Moreover, space solar power systems appear to possess many significant environmental advantages when compared to alternative approaches to meeting increasing terrestrial demands for energy - including requiring considerably less land area than terrestrially-based solar power systems.

The economic viability of such systems depends, of course, on many factors and the successful development of various new technologies - not least of which is the availability of exceptionally low cost access to space. However, the same can be said of many other advanced power technologies options. Space solar power may well emerge as a serious candidate among the options for meeting the energy demands of the 21st century.

In 2007, a major study by the Defense Department's National Security Space Office gave the concept another boost, concluding that "there is enormous potential for energy security, economic development, improved environmental stewardship . . and overall national security for those nations who construct and possess a SBSP capability."

The study group further declared, "Space-Based Solar Power is more technically executable than ever before and current technological vectors promise to further improve its viability."

So much for the concept. Can Solaren really deliver electricity to PG&E customers by 2016, the year it has contracted to begin commercial operation?

If Solaren succeeds, PG&E's customers have a great opportunity to benefit from affordable clean energy. There is no risk to PG&E customers; PG&E has contracted only to pay for power that Solaren delivers.

Solaren will work with citizen groups and government agencies to support the project's development. Solaren is responsible for getting all the necessary permits and approvals from federal, state and local agencies. Among other things, Solaren will have to prove that its technology satisfies all applicable safety standards, an issue that space power enthusiasts have addressed in detail, but is nonetheless sure to be controversial.

From PG&E's perspective, as a supporter of new renewable energy technology, this project is a first-of-a-kind step worth taking. If Solaren succeeds, the world of clean energy will never be the same.

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