MIT – solar energy is, at least in theory, sufficient to meet all of humanity’s energy needs, the question becomes: “How big is the engineering challenge to get all our energy from solar?” Taylor says.
Solar thermal systems covering 10 percent of the world’s deserts — about 1.5 percent of the planet’s total land area — could generate about 15 terawatts of energy, given a total efficiency of 2 percent. This amount is roughly equal to the projected growth in worldwide energy demand over the next half-century.
Solar energy is a vibrant research topic, attracting scientists interested in many different approaches. For example, MIT researchers Angela Belcher and Paula Hammond are exploring approaches to solar power that would harness the power of biological organisms to create solar devices; Penny Chisholm and Shuguang Zhen are looking into the possibility of directly harnessing the photosynthesis done by plants or single-celled organisms; and various researchers including Vladimir Bulovic, Michael Strano, Tonio Buonassisi, Jeffrey Grossman and Yang Shao-Horn, among others, are working on ways of improving the efficiency or lowering the costs of solar photovoltaic cells.
Still others are pursuing a variety of approaches to solar thermal energy: using the sun’s heat to power turbines or to heat homes or water. A significant breakthrough in any of these areas could make solar power an economically viable option for the world’s energy needs. This year, for example, Alexander Slocum and others published a proposal for a solar thermal system that could provide steady, 24/7 baseload power for utility companies, helping to make it cost-competitive with other sources.
Other researchers are studying ways to make effective solar-power systems using common, inexpensive materials. For example, cadmium telluride is a very promising material for solar cells. But it turns out that tellurium, one of its ingredients, is “rarer than gold,” Jaffe says. “We need to be able to make solar cells out of common materials, or at least things that are not exquisitely rare,” he adds.