During the daytime, the batteries accumulate energy while the plane climbs to a height of up to 30, 000 feet.

WSJ: A Solar-Powered Plane Travels Light | WSJ. Magazine May 2013

But while you could very credibly argue that the ruble was becoming dangerously overvalued during the height of the 2007-08 energy boom, at the present time it would appear that, if anything, the ruble is actually modestly undervalued.

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Sacyr was one of a trio of big Spanish construction companies that grabbed stakes in the country's biggest energy firms in the go-go days of 2006, near the height of Spain's property bubble.

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Nearly the entire Republican caucus, not to mention a handful of Democrats, are already on record voting for this concept in the August 2008 vote on the New Energy Reform Act, introduced by the so-called Gang of 10 during the height of the oil price spikes in 2008.

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"Kites are opportunistic scavengers, to conserve energy they feed mostly on worms and small dead animals, which they can see from a great height", Mr Straughan said.

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In the height of winter, cold temperatures slowed the rate of lay as hens sought to preserve their energy.

FORBES: Natural Protection

Solar energy speculators want to build a solar tower facility in Arizona that would be more than three times the height of the Eiffel Tower.

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The Energy Department also noted that U.S. oil demand normally peaks in July and August, the height of American vacation season, and that the release should help alleviate the seasonal price spike somewhat.

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