It took a crisis to shift Roger Angel’s gaze from the stars back to Earth, but we may all benefit from his full attention, locked as it is on helping crack the problem of global warming.

Angel’s expertise lies with telescopes and astronomy, so it seems fitting that he views the sun as our greatest hope in reducing dependence on fossil fuels. His first efforts focused on geo-engineering a way out of warming, by either pumping sulfur aerosols into the stratosphere, or constructing a giant sunshade, to block the sun’s impact. He figured these fixes could work relatively quickly, but might deliver negative side effects, and in the case of the giant space screen, cost in the trillions. Regarding this orbiting sun deflector, Angel tells us that “the present administration of NASA thinks it’s stupid” and won’t fund it. So he has been exploring alternative solutions.

One idea was to create a necklace of satellites in geosynchronous orbit around the Earth that could collect the undiluted energy of sunlight, convert it to microwaves, and then beam it back home. To generate 3000 gigawatts of electrical power, we would need 600 of these satellites. This idea proved very expensive, due to the launch weight of each of the space solar power stations – upwards of 70 thousand tons. Until space travel and construction become routine, this idea can’t fly, believes Angel.

He’s far more optimistic about the development of massive, ground-based solar arrays, planted on hundreds of square miles in the desert. In the U.S., this means Angel’s own backyard, in Arizona, and other states along the border with Mexico. He sees these solar collection farms operating year-round, and transmitting electricity via intercontinental transmission lines to the coasts of the nation. Angel says this form of transmission is a proven and relatively inexpensive technology. He suggests using Lake Mead or other western waters as giant hydroelectric storage facilities. He is devising a prototype photovoltaic array using an abandoned PBS communication dish, and in his university workshop milling mirrors that are intended to concentrate the light of sunshine by a factor of 1000. In the Southwest, Angel says, “there is enough sunshine on a couple hundred miles square to feed the whole nation."

ABOUT THE SPEAKER:
Roger Angel received his D. Phil. from Oxford University, and his M.S. from the California Institute of Technology. Prior to his appointment at the University of Arizona in 1973, Angel was an associate professor at Columbia University.

He was a MacArthur Fellow from 1996 to 2001, and is a Fellow of the Royal Society, and of the American Academy of Arts and Science and of the Royal Astronomical Society. He is also a member of the National Academy of Sciences.