Shift Key Summer School: How Sun and Wind Become Electricity

The two fastest-growing sources of electricity generation in the world represent a radical break with the energy technologies that came before them. That’s not just because their fuels are the wind and the sun.

This is our third episode of Shift Key Summer School, a series of “lecture conversations” about the basics of energy, electricity, and the power grid. This week, we dive into the history and mechanics of wind turbines and solar panels, the two lynchpin technologies of the energy transition. What do solar panels have in common with semiconductors? Why did it take so long for them to achieve scale? And what’s an inverter and why is it so important for the grid of the future?

Shift Key is hosted by Jesse Jenkins, a professor of energy systems engineering at Princeton University, and Robinson Meyer, Heatmap’s executive editor.

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Here is an excerpt from our conversation:

Jesse Jenkins: And so then the other thing, of course, that helps is putting it at a place that’s sunnier, right? In addition to pointing it at the sun, you need to have the sun in the first place. If you go from a cloudy northern latitude to a sunny southern latitude, you’re going to get more production. That variation isn’t as large as you might think, though, from the best site in, say, Arizona and New Mexico to the worst 10th percentile sites in northern Maine or Portland, Oregon, where I grew up, where it’s very cloudy. That difference in solar resource potential is only about a factor of two. So I get about twice as much solar output from an ideally placed panel in Arizona as I do in Portland, Oregon, or Portland, Maine. That’s a lot, but we can find much better resources much closer to Portland, Maine, and Portland, Oregon, right?

And so this is why it doesn’t really make sense to build a giant solar farm in Arizona and then send all that power everywhere else in the country — because the transmission lines are so expensive and the efficiency gain is not that huge, it doesn’t make sense to send power that far away. It might make sense to put my solar panel on the east side of the Cascade Mountains and send them to Portland, Oregon, but not to go all the way to Arizona. Because the variation in solar potential is much more gradual across different locations and doesn’t span quite as much of a range as wind power, which we can talk about.

Robinson Meyer: I was going to say, this idea that solar only varies by, it sounds like, about 100% in its efficiency.

Jenkins: Or capacity factor.

Meyer: Yeah. I suspect, in fact, from previous conversations that this is going to be an important tool that comes back later — this idea that solar only really varies by 100% in its resource potential, that Arizona solar is only twice as good as Maine solar, is going to be really important after we talk about wind.

Mentioned:

How Solar Energy Became Cheap, by Gregory F. Nemet

More on what wind energy has to do with Star Trek

This episode of Shift Key is sponsored by …

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Music for Shift Key is by Adam Kromelow.