In the 1970s, Buckminster Fuller proposed superconducting global-scale electrical grids to wheel solar energy collected on the daylight hemisphere halfway around the earth to the nighttime hemisphere.

Given the potential for catastrophic climate change, a question must be asked: What has happened to such far-out and disruptive – but not necessarily unfeasible – visions for a renewable-energy future? Right now, hundreds of new coal plants are on drawing boards around the world.

Today, the world uses about 13 terawatts of power, approximately 80 percent of it from carbon-dioxide-emitting fossil fuels. If we want to keep Earth’s average temperature low enough to prevent eventual large sea-level rises (see “The Messenger”) – and also accommodate continued 3 percent annual economic growth – we will need between 10 and 30 terawatts of new carbon-free power by 2050.

The time to start building a sustainable carbon-free energy infrastructure is now. We need Apollo-type research to accomplish this, beginning perhaps with funding of far-out programs along the lines of ARPA-E (“E” for energy), an initiative proposed by the National Academy of Sciences and modeled on the U.S. Advanced Research Projects Agency (now prefaced by “Defense”), which gave us the Internet.

A global-energy-systems engineer – if such a profession existed – would probably have recourse to many technologies that are disruptive of today’s powerful coal, oil, and gas industries. Wind turbines are already economically competitive with conventional energy sources in some regions. Steadier and faster high-altitude winds might be harvested someday by flying wind turbines that transmit electricity to Earth through tethering wires.

The greatest potential for terawatt-scale renewable electric power lies in harvesting solar energy directly. About 2,000 megawatts of silicon-based photovoltaic cells have been manufactured, but the existing technology is expensive. A promising path to cost reduction is thin-film cells that include materials like copper indium diselenide, cadmium telluride, and amorphous silicon. Aggressive R&D and expanding markets will reduce costs, but a big push from government could help realize solar’s vast potential.