A Way to the Most Abundant Energy

MIT energy initiative: photocell boards

Viable solar energy has been a long-sought-after goal, but with new and affordable technologies, we might soon be able to make the switch

We have come a long way in taming the sun’s chaotic energy since 19th century efforts to create a solar motor. Today we can efficiently heat water and buildings and even generate substantial transmittable power all from this abundant light source.

Our ability to make use of this power source has coalesced into two distinct flavors. First, we have finite, localized systems: the solar hot water heaters, passive solar heating and the like, where solar energy must be used or stored at the production site, or else it is lost. Second, we have developed more universal technologies, which generate electricity. These systems include photovoltaics—the direct conversion of sunlight into electricity via semiconductors—and concentrated solar power—the production of electricity via high-temperature steam turbines or thermodynamic engines. All solar technologies have been growing steadily over the past couple of decades, but the progress has been truly remarkable with photovoltaics: more than 1,000-fold since the late 1980s and continuing at a robust pace.

Solar is the most abundant energy resource on planet Earth. Even after accounting for weather variation, the average solar power received by the continents alone peaks at 23 million gigawatts. For comparison, a standard size nuclear power plant is one gigawatt. It dwarfs all the other renewable energy resources combined—including wind, hydropower and geothermal—and one year’s worth of solar would far exceed the reserves of finite energy resources (nuclear and fossil) even when counting unconventional shale and deep-sea oil and methane.

Unfortunately, unlike countries such as even the relatively cloudy Germany, solar as an energy source still goes largely unnoticed in the U.S., where the resource is still viewed as marginal by many in decision-making positions. In particular, there is a widely held perception that:

• The solar resource requires too much space to exploit.
• Solar energy is too expensive.
• Intermittency caused by weather, day-night cycles and seasons is a showstopper.

Compared with many other energy sources, solar can require relatively little space to create power.

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