Maximum fuel economy is achieved in ECO mode, with the stop-start on and engine response and output dialed way back.

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Multiple operating modes will allow the driver to tailor various performance parameters to accentuate maximum fuel economy or a sportier response as desired.

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It offers remarkable fuel efficiency--more on that in a minute--but the tradeoff is that it takes 27 minutes to get from sea level to 41, 000 feet, which is both the Mustang's maximum operating altitude and its most fuel-efficient.

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This allows the vehicle to run at maximum torque all the time, and could thus reduce fuel consumption by up to 30%, according to Peter Augustsson, the company's president.

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By limiting the speed limit of its trucks to a maximum 60 miles per hour, the company estimates that it can save 3.75 million gallons of diesel fuel and cut carbon dioxide waste by 83 million pounds per year.

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Second, nuclear reactors can only be run above maximum capacity for a short period before they begin experiencing complications, so each region maintains backup facilities to burn fuel oil or natural gas at peak periods or for when the nuclear reactors are offline.

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