Solar

Enough of the sun's energy reaches the earth's surface to satisfy all our energy needs. The trick is harnessing it in usable form. Solar cells made of silicon convert sunlight into electricity, which is then wired to the power grid. For decades, they've powered calculators, satellites, and homes. Scientists are experimenting with other materials to capture more of the sun's power and cut manufacturing costs. One technique, known as concentrating solar power, uses an array of mirrors, lenses, and liquid-filled tubes to turn the sun's intense heat into steam, which then powers an electric turbine. Advances could one day allow the sun to replace coal and nuclear plants as our main source of electricity.  Learn more from Natural Resources Canada.

Wind

It currently accounts for only 1 percent of U.S. electrical production. Yet it's the fastest-growing energy source, representing a third of all new power generation in 2007. The basic technology-a rotor to capture the wind's energy and a shaft to convert it-hasn't changed much since the Dutch used windmills to grind grain. In the modern version, aerodynamic rotor blades grab the wind, and a generator converts the mechanical energy into electricity. The Midwest and Plains states have the highest wind potential, with Texas already leading the way. New York City mayor Michael Bloomberg envisions an offshore wind farm that could supply 10 percent of the city's electricity needs within a decade.  Contact the Canadian Wind Energy Association (CanWEA) for more information.

Biofuel

Ethanol, an alcohol produced through the fermentation of corn or other crops, has been touted as a petroleum substitute for decades, particularly in the Midwest, where corn is king. But the dramatic rise in oil prices has triggered a biofuel boom. That, in turn, has led to talk of an ethanol glut as more and more farmers join the new gold rush. Other plant-based fuels include biodiesel, which can be made from vegetable oil (even restaurant grease).

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