Work is starting in Wyoming coal country on a new type of reactor. Its main backer, Bill Gates, says he’s in it for the emissions-free electricity.

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The new principles aim to define ‘high-integrity’ offsets amid concerns that current practices often don’t cut greenhouse gas emissions as claimed.

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The Federal Energy Regulatory Commission approved the biggest changes in more than a decade to the way U.S. power lines are planned and funded.

© Renaud Philippe for The New York Times