According to the Electric Power Research Institute (EPRI) pathway to the future for electric power "Roadmap," we must implement new, breakthrough energy concepts to provide sustainable energy for the 10 billion global population expected by the year 2050. Collecting solar energy in space may be one way to fit the bill.

As reported in the latest issue of the EPRI Journal, sun-facing photovoltaic arrays in stationary Earth orbit at an altitude of 22,300 miles would receive eight times as much sunlight as they would at the earth's surface, on average. Space arrays would remain unaffected by the Earth's day-night cycle, cloud cover, and atmospheric dust. Therefore, transmitters connected to large space-based solar photovoltaic arrays could beam as much as several billion watts of power to Earth at microwave radio frequencies for collection by a wide area rectifying ground antenna.

John Mankins, NASA's manager for advanced concept studies, says recent developments in information technologies, robotics, power generation, and electronics promise to reduce the costs of a space power system (SPS). According to Mankins, the physics and fundamental technology for such a scheme are well known and largely in hand, although substantial development would be necessary to actually build an SPS.

"Solving the ‘trilemma' of population growth, resource consumption, and environmental cost, and providing a sustainable global supply of electricity will require some ‘outside the box' thinking," says Kurt Yeager, EPRI's president and CEO. "To look beyond the planet for a solution is indeed thinking outside the box."

Scientists envision building solar collectors on the moon will provide an elegant solution to launch the heavy mass of satellite components into orbit. This would also solve the problem of debris from satellites that could threaten commercial satellites and space flights from Earth. The lunar soil could supply silicon to build solar arrays and metals, such as iron and aluminum, for support structures and electric wiring. The components and production processes could be developed and tested on Earth before returning to the moon.

According to David Criswell, director of the Institute for Space Systems Operations at the University of Houston, lunar solar power could supply a 2050 world population of 10 billion people with enough energy to meet all human needs at a low cost; with few (if any) environmental downsides of other energy alternatives.

Most ardent believers in the potential for space-based solar power stop short of suggesting an urgent, capital-intensive development effort should be immediate. Obviously, many technical,economic, environmental, legal, and regulatory issues need to be resolved before we could reach an international consensus. Supporters of space solar power say the significant progress achieved thus far in demonstrating the technology and feasibility of wireless power transmission from space makes the case for pursuing the program.

This article was excerpted from the EPRI Journal Spring 2000 issue.