You could point fingers in several directions for the outages that stemmed from last week’s polar vortex obliteration of the Texas power grid. You can’t rightly blame Earth for doing what it does, but you could certainly condemn the state’s deregulation of its energy system. Texas also remains heavily reliant on fossil fuels, and the power plants that run on them failed en masse. So you might blame those operators, but you can’t blame renewables for this one.
But you’re not likely to see many people pointing fingers at the obscure yet fascinating eccentricities of the fragmented United States energy grid. And you’re even less likely to hear that what happened in Texas could help spur the country to better prepare its grid for the ascent of renewables—and our descent into the ravages of climate change.
In the future, the central challenge for the US will be obtaining power that is both clean and “firm,” in the parlance of energy nerds. “The real failing of Texas was the reliance upon the natural gas backbone as the firm power source, which of course wasn’t so firm, as they later learned,” says David Victor, a political scientist at the University of California, San Diego. He’s a coauthor on a National Academies of Sciences, Engineering, and Medicine report coincidentally released today called The Future of Electric Power in the United States. “If you want to decarbonize the grid, and keep power reliable, then you’ve got to have a clean, firm power source,” he continues. “That’s the central goal.”
But the US grid isn’t going to make the wide-scale sharing of clean energy easy—exporting solar energy from the Southwest, for instance, and wind energy from the Midwest. That’s because the mainland grid is divided into three sections. The Western Interconnection and the Eastern Interconnection meet at the eastern borders of Colorado and Wyoming, splitting the country in two. The Texas Interconnection is divorced from both in the name of energy independence, though it doesn’t trace neatly to the state’s borders—some of the panhandle is actually part of the Eastern Interconnection. And in the northern and southern parts of the US, our grids intertwine with those run by our neighbors. There’s a Quebec grid that exchanges power across the border with New England. The Pacific Northwest similarly exchanges with British Columbia, and Southern California with a little bit of Mexico’s Baja California Peninsula.
Each of these grids more or less does its own thing: Utility companies generate power and ferry it around their territories. These utilities are typically owned by a state, a municipality, or investors. The utilities regularly exchange power within an interconnection as energy demand waxes and wanes in a given area thanks to heat waves or cold snaps. So, for instance, in the West, high-voltage transmission towers carry electricity between Washington, Oregon, and California. But neither the eastern nor the western half of the national grid sticks tendrils into Texas in a way that would have let the state borrow large amounts of power when facing a massive, sudden freeze.
First of all, Texas would have had to fall back on a neighbor that was far enough away to not also be suffering an extreme cold snap. (Nearby states would be dealing with their own high energy demand and generation problems.) Even then, Texas could draw maybe 1 gigawatt of power from the Eastern Interconnection on a good day. For perspective, the state’s entire grid uses 60 gigawatts.
It’s not that the Western and Eastern Interconnections don’t exchange any power at all—they do it here and there at the local level. But they’re not thoroughly connected by those big high-voltage lines, which are the only way to carry electricity long distances. The Rocky Mountains quite effectively separate East and West. “It’s really evolved that way because in that part of the country, there just wasn’t much infrastructure,” says Jeff Dagle, chief electrical engineer at the Pacific Northwest National Laboratory. “And so nobody had an economic reason to build a bunch of high-voltage transmission lines to connect the grids together.”
And there’s another engineering challenge: The Western and Eastern Interconnections each hum at their own uniform frequency. If you had two meters and plugged one into a wall socket in San Francisco and the other in Seattle, you’d see the same readout. “Every motor, every generator, everything in that grid is running at the same speed in that entire grid,” says Dagle. “It’s kind of cool to think about.” But if you plugged a meter into a socket in New York City, it would be humming at the Eastern grid’s frequency. And, of course, you’d get a different reading in Dallas.