It’s Friday, May 10, and the U.S. just surpassed 2 million solar installations.

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Noticed any new solar arrays on your neighbors’ roofs? I’m guessing you have, since the United States just hit a new milestone: 2 million solar installations. Here’s why that’s a big deal: It took the U.S. 40 years to accomplish the first million solar installations. Guess how many years it took us to install the second million? Three.

That’s good news both for the solar industry and the planet. More solar means more energy generated without greenhouse gas emissions. The number of new sun-powered energy installs is on track to double again in five years, according to the solar association that did the analysis, and by the time we’re deep into the 2020s, solar will become “the dominant new form of energy generation.” Whew! That was fast.

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The residential sector — people putting up solar panels on their houses — is pushing the rapid growth in the solar industry. As prices keep falling, more and more folks will invest in the green energy. Already, 12 million homes across the nation get their power from solar, the analysis says.

California is still leading the charge in terms of new installations, but places like South Carolina are gung ho about solar, too. “According to our latest forecasts, by 2024, there will be on average, one solar installation per minute,” said Michelle Davis, senior solar analyst with Wood Mackenzie, which contributed to the study.

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