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As more places move to renewable energy, some people are asking whether this puts the electric grid at risk. An Energy Department study on the issue is due out soon. Energy Secretary Rick Perry wants to know if too much wind and solar threatens the grid's reliability. That's something that's also being debated in North Dakota. Prairie Public Broadcasting's Amy Sisk explains.
AMY SISK, BYLINE: Steven Somsen's farm is flat with wheat and soybeans that will soon grow as far as the eye can see. Last year, it got a new addition.
STEVEN SOMSEN: We ended up with some towers on our property.
SISK: Spinning, white wind turbines - three of them. There's 100 in total dotting farmland around his rural community of Courtenay. Somsen will have to navigate his farming equipment around them, like the sprayer he's working on today.
SOMSEN: It's something different to look at. And some of them - they say that they don't like them. And the other ones say it's fine - don't bother me none.
SISK: The windy Great Plains are prime territory for these giant towers. This is making North Dakota's coal industry uneasy. A decade ago, coal produced 90 percent of the state's power. Today it's down to 71 percent as wind fills in the gap. This spring, Republican State Senator Dwight Cook tried to halt new wind farms for two years. His proposal ultimately failed.
DWIGHT COOK: Clean is great, but we still got to have reliability. We can't let go of that because without reliable electricity, we're in the dark.
SISK: He wants to make sure all these wind turbines don't cause blackouts. See; for decades, reliable electricity meant coal, which provides a constant stream of power. But cheap natural gas and wind have displaced coal, and that's likely to continue. There are federal tax credits and state mandates for renewables. And more and more cities say they plan to move to all-renewable power.
Back in Courtenay, I'm standing with Jayme Orrack as enormous blades rotate above us on a breezy day. He oversees this new wind farm for Xcel Energy, a Midwest-based utility.
JAYME ORRACK: Takes about a minute and a half for it to come online. It has to stay at a sustained thousand RPM on the - in the generator before it will actually kick on and start generating power.
SISK: Unlike a coal plant, wind can fire up really quickly to meet the demand for power. But wind isn't always blowing. Grid operators are finding ways around that.
RENUKA CHATTERJEE: Ultimately when you think about reliability, you're trying to maintain balance of supply and demand.
SISK: Renuka Chatterjee is with MISO. The Midcontinent Independent System Operator oversees the grid in the Midwest. She says utilities are getting savvy about forecasting when the wind will blow, and they're spacing out new wind farms so that as the wind shifts, one farm can power up as another powers down.
CHATTERJEE: As you think about each resource, they bring a unique profile. And we need a balance of those resources. Wind alone doesn't cause reliability issues.
SISK: In a future with even more renewables, innovation will be key. Judy Chang is an economic and energy consultant with the Brattle Group.
JUDY CHANG: There's no doubt in my mind that the customers of the future will want a cleaner grid. And there's no doubt in my mind there will be more usage of electricity to power our economy. Given that, we should think about how to structure into that future.
SISK: But if the country plans carefully enough, she says there's no real limit to how much renewable energy the grid can one day handle. For NPR News, I'm Amy Sisk in Bismarck.
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