Sign In or Create an Account.

By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy

Podcast

Shift Key Summer School: How Do Power Markets Work?

Jesse gives Rob a lesson in marginal generation, inframarginal rent, and electricity supply curves.

Power lines.
Heatmap Illustration/Getty Images

Most electricity used in America today is sold on a wholesale power market. These markets are one of the most important institutions structuring the modern U.S. energy economy, but they’re also not very well understood, even in climate nerd circles. And after all: How would you even run a market for something that’s used at the second it’s created — and moves at the speed of light?

On this week’s episode of Shift Key Summer School, Rob and Jesse talk about how electricity finds a price and how modern power markets work. Why run a power market in the first place? Who makes the most money in power markets? How do you encourage new power plants to get built? And what do power markets mean for renewables?

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

Subscribe to “Shift Key” and find this episode on Apple Podcasts, Spotify, Amazon, YouTube, or wherever you get your podcasts.

You can also add the show’s RSS feed to your podcast app to follow us directly.

Here is an excerpt from our conversation:

Jesse Jenkins: If I’m just a utility operating on my own, I want to basically run my fleet on what we call economic dispatch, which is rank ordering them from cheapest to most expensive on a fuel or variable cost basis, and trying to maximize my use of the less expensive generators and only turn on the more expensive generators when I need them.

That introduces this idea of a marginal generator, where the marginal generator is the last one I turned on that has some slack to move up or down as demand changes. And what that means is that if I have one more megawatt-hour of demand in that hour — or over a five-minute period, or whatever — or 1 megawatt-hour less, then I’m going to crank that one generator up or down. And so the marginal cost of that megawatt-hour of demand is the variable cost of that marginal generator. So if it’s a gas plant that can turn up or down, say it’s $40 a megawatt-hour to pay for its fuel, the cost on the margin of me turning on my lights and consuming a little bit more is that that one power plant is going to ramp its power up a little bit, or down if I turn something off.

And so the way we identify what the marginal value of supplying a little bit more electricity or consuming a little bit more electricity is the variable cost of that last generator, not the average cost of all the generators that are operating, because that’s the one that would change if I were to increase or decrease my output.

Does that make any sense?

Robinson Meyer: It does. In other words, the marginal cost for the whole system is a property of the power plant on the margin, which I realize is tautological. But basically, the marginal cost for increasing output for the entire system by 1 megawatt-hour is actually a property of the one plant that you would turn on to produce that megawatt-hour.

Jesse Jenkins: That’s right, exactly. And that can change over the course of the day. So if demand’s really high, that might be my gas plant that’s on the margin. But if demand is low, or in the middle of the day, that gas plant might be off, and the marginal generator during those periods might be the coal plant or even the nuclear plant at the bottom of the supply curve.

Mentioned:

Jesse’s slides on electricity pricing in the short run

Jesse’s lecture slides on electricity pricing in the long run

The duck curve

Shift Key Summer School episodes 1, 2, and 3

This episode of Shift Key is sponsored by …

Accelerate your clean energy career with Yale’s online certificate programs. Gain real-world skills, build strong networks, and keep working while you learn. Explore the year-long Financing and Deploying Clean Energy program or the 5-month Clean and Equitable Energy Development program. Learn more here.

Join clean energy leaders at RE+ 25, September 8–11 in Las Vegas. Explore opportunities to meet rising energy demand with the latest in solar, storage, EVs, and more at North America’s largest energy event. Save 20% with code HEATMAP20 at re-plus.com.

Music for Shift Key is by Adam Kromelow.

Yellow

You’re out of free articles.

Subscribe today to experience Heatmap’s expert analysis 
of climate change, clean energy, and sustainability.
To continue reading
Create a free account or sign in to unlock more free articles.
or
Please enter an email address
By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy
Energy

The Infrastructure Investor Still Bullish on Renewables

Generate Capital’s Jonah Goldman makes his case.

Money and renewables.
Heatmap Illustration/Getty Images

The Inflation Reduction Act sparked a predictable surge in clean energy-related investments from the law’s signing in 2022 through the 2024 election, before President Trump’s second term ushered in an era of cancellations, closures, and downsizing. Of the domestic projects announced since the IRA’s passage, a total of 35 have been nixed or scaled back so far this year — more than in all of 2023 and 2024 combined, according to estimates from the environmental advocacy organization E2. This accounts for over $22 billion in lost investment and 16,500 in lost jobs.

“There’s a drastic decrease in the amount of new [clean energy] investments,” E2’s Michael Timberlake told me. After the IRA’s passage, he explained, nearly every month saw over a billion dollars invested in new clean energy projects. But since December of last year, monthly investment has come in below a billion dollars more often than not.

Keep reading...Show less
Green
Politics

AM Briefing: Ford’s EV ‘Model T’ Moment

On Interior’s birdwatching, China’s lithium slowdown, and recycling aluminum

Ford’s EV ‘Model T’ Moment
Heatmap Illustration/Getty Images

Current conditions: Hurricane Erin is gathering strength as it makes its way toward Puerto Rico later this week • Flash flooding and severe storms threaten the Great Plains and Midwest • In France, 12 administrative regions are on red alert for heat as temperatures surge past 95 degrees Fahrenheit.


Keep reading...Show less
Yellow
Electric Vehicles

Ford’s Model T Moment Isn’t About the Car

The assembly line is the company’s signature innovation. Now it’s trying to one-up itself with the Universal EV Production System.

A pickup truck and a diagram.
Heatmap Illustration/Getty Images

In 2027, Ford says, it will deliver a $30,000 mid-size all-electric truck. That alone would be a breakthrough in a segment where EVs have struggled against high costs and lagging interest from buyers.

But the company’s big announcement on Monday isn’t (just) about the truck. The promised pickup is part of Ford’s big plan that it has pegged as a “Model T moment” for electric vehicles. The Detroit giant says it is about to reimagine the entire way it builds EVs to cut costs, turn around its struggling EV division, and truly compete with the likes of Tesla.

Keep reading...Show less
Blue