A growing percentage of our electricity comes from solar and wind power. Both of these sources are plentiful, but both sunshine and wind come and go. To really depend on these energy sources, we need to be able store the energy they generate when they are most productive so we can use it at other times.
Large-scale, economic energy storage is the Holy Grail for creating a renewable-based grid. Researchers are exploring different ways of achieving this. A number of efforts have focused on batteries— but they are not the only answer.
There is growing interest in using liquid air as an energy storage medium. The energy from a wind or solar plant is used to liquify air, which is then stored. When power is needed, the liquid air is heated, and expanded to run turbine generators. The cycle of liquefaction, compression, expansion, and generation is actually very energy efficient.
This technology has a number of appealing features. For one, it is environmentally friendly. For another, the infrastructure to accomplish it is largely in place. Liquefying air is already a big industry with existing components and supply chains all over the world.
There is increasing optimism that solar and wind power can supply most of the energy we need, but the intrinsic nature of both of these sources makes them unreliable for providing power on demand. If we can store the energy we get from the sun and wind for use when we need it, we can overcome the biggest hurdle to really going green.
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Liquid air technology could boost the role of renewable energy
Photo, taken September 25, 2010, courtesy of Rick Willoughby via Flickr.
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Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.