"Supercritical" means the boiler runs at a high temperature (1, 100 degrees Fahrenheit), increasing thermodynamic efficiency.

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Despite the fact that it likely contains water and a rocky core, that water is almost certainly in the form of steam or a supercritical fluid.

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That depth provides enough pressure to turn CO2 into what is known as a supercritical fluid, a form in which the stuff is more likely to stay put.

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Over 17 years it has built seven plants (five others are in construction) nationwide and has become quite nimble at navigating the permit process. (It's easier to get approvals if you're a private company than if you're a public utility.) In 2004 LS filed a proposal to build a 1, 600-megawatt, supercritical pulverized-coal plant in White Pine.

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