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Vox: Texas’s wind and sunlight complement each other exceptionally well. That’s huge for its grid.

Posted by Umair Irfan on Jan 8, 2019

Vox presents findings from a new Rice University study that shows solar and wind energy resources in Texas complement each other well. The piece dives into what is needed for the state to reimagine its power grid to leverage this power, and includes a reference to a Brattle Report produced for AEE Institute that estimated ERCOT could feasibly integrate 50 percent of renewables. See excerpts below and read the entire Vox story here.

The astounding growth in wind and solar power coupled with their plummeting prices means that we are now radically rethinking how we produce, transmit, and sell power. Customers want 100 percent renewable energy, states want to cut their greenhouse gas emissions, and utilities are scrambling to come up with new business models and infrastructure to accommodate them.

The wind and the sun are some of the most abundant sources of energy in the world, and they’re free. But the big challenge of harnessing them is the simple fact of their intermittent availability: In general, the sun shines during the day, which means the amount of solar energy available is highest during the day. Wind, meanwhile, is usually strongest at night, so wind energy peaks after sunset.

Given this difference, one source could — in theory — compensate for the other’s lulls. But in practice, few places in America have enough sunlight and wind to balance each other out.

One place that happens to have plenty of both? Texas.

Researchers at Rice University recently mapped out the Lone Star State’s breezes and sunshine to assess what they called “complementarity,” how the energy available from one energy source rises and falls in relation to another. If a wind turbine farm’s highs occur as a solar array’s output bottoms out and vice versa, the generators are said to have high complementarity. By making power output more consistent, complementarity makes the grid more reliable, easier to schedule power, and cheaper.

What the Rice team found is that patterns of wind and sunshine in Texas complement each other exceedingly well, helping the grid provide enough power even at moments when electricity demand is highest, like during the searing summer heat when hundreds of thousands of air conditioners are switched on...

To be clear, the findings don’t show that Texas could pull off a 100 percent renewable energy grid just yet. But they do show that renewables could replace a whole lot of dirty energy without breaking much of a sweat.

Though coal is increasingly being priced out of the market, it still provides about one-third of the state’s electricity. Wind provides roughly 17 percent, and solar barely registers. So renewables still have plenty of ground to gain, and the state is uniquely positioned to balance out its grid with the wind and solar resources it has...
 A 2015 report from the Brattle Group for the Advanced Energy Economy Institute found that ERCOT could feasibly integrate upward of 50 percent renewable energy using existing technology “with modest operational changes.” Yet energy prices also remain low, making the economics of building new power plants more difficult, especially for more renewable energy and transmission along the lines of the CREZ buildout...

But when reaching about 80 percent penetration of renewables, some of the quirks that come with intermittent sunlight and wind become much more difficult to reconcile with how we use energy. And even at a lower share of the power mix, there are still some gaps between the times when solar panels and wind turbines produce electricity.

“The difficulty is the transition periods (early morning and post-sunset) [where] there are physical reasons why wind and solar in these timeframes are harder to get anti-correlations emerging regularly,” Clack said in an email.

That means utilities will still need some kind of reserve power, though likely not at the immense scales usually assumed to be needed with renewables...

Read the entire Vox story here.

Topics: AEE In The News