Soil and plants also keep the sun off the roof layer itself, making it last longer.

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Microbes and plants harvest energy from the sun and drive environmental cycles.

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Some foresee hybrid wind-gas and solar-gas plants, with gas producing electricity when sun and wind are weak.

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It's trying to sell its solar product to industrial customers, including coal-fired plants, which would use both the sun and coal to make steam.

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Located under maple trees, the bed is filled with plants that require only a few hours of sun a day.

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"The plants don't get overstressed under the sun... at the same time they can get nutrients in the water equally, " says Ng.

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Low cost improvements can include replacing incandescent lights with CFL or LED alternatives, master switches to make it easier to switch off appliances at night, energy monitoring to make it easier to identify waste, draft proofing, and using plants or shade-cloth to keep the summer sun off your home.

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