image credit: William W Nazaroff (2005); image source; larger image

The Geothermal Power Plant

The above photo shows the Nesjavellir geothermal plant in Iceland, which produces power and hot water for the towns surrounding it.

Iceland sits astride the mid-Atlantic ridge, where two tectonic plates are moving apart at about two and a half centimeters per year. Magma--molten rock--wells up in between the plates and heats the bedrock under Iceland. The bedrock heats the groundwater that the plant pipes to the surface to make a mixture of steam and brine (salt water).

For more on tectonic plates and Iceland, including a volcanic island nearby that was formed in 1963, see Physics to Go, Issue 55.

(This feature was updated on July 25, 2013.)

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U.S. Department of Energy: Energy Efficiency & Renewable Energy

Beyond the search for renewable energy sources, a complementary approach is to save energy by using it more efficiently. See this California state government website to find out how changes to your home and your lifestyle can help. To learn more, visit U.S. Department of Energy: Energy Efficiency & Renewable Energy.

(This feature was updated on July 25, 2013.)

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Caltech Researchers Create Highly Absorbing, Flexible Solar Cells

In a radical departure from the traditional design, a Caltech group has produced a flexible solar cell using an array of silicon wires. By packing light-scattering particles in among the wires, the researchers have achieved efficiencies up to 85%, despite the fact that the silicon wires take up only 2% of the volume, with significant cost reduction expected in a commercial version. To learn more, see this Caltech press release and this Scientific American article.

'Major discovery' from MIT primed to unleash solar revolution

An MIT group has figured out how to split water molecules to produce hydrogen and oxygen gas, in a tabletop experiment using inexpensive materials. The energy to run the reaction comes from electricity. The goal, though, is to power the experiment by sunlight--very similar to photosynthesis, except that the products are oxygen and hydrogen gas instead of sugar.

The long-term plan of this MIT research is to store energy during the day in hydrogen gas, and then use the hydrogen and oxygen in a fuel cell to provide electricity at night. To learn more, see this MIT press release.