E8: Transmission: power to the people

LHF: Hello, and welcome back to Today I Learned: Climate, the climate change podcast of the Massachusetts Institute of Technology. I’m Laur Hesse Fisher.

If you asked me, how do we make our electricity cleaner and cheaper, I would probably talk about solar and wind and batteries, and the promise of geothermal and nuclear. I wouldn’t start by talking about the power lines running into the homes along my block.

But our guest today makes the case that maybe I should.

JH: Look, transmission’s not a sexy thing. You know, it doesn't have windmills, it doesn't have cooling towers. It's a nuisance. No one wants to look at the lines. But I think it's probably the single most important piece to improving reliability and reducing costs.

LHF: That’s Joshua Hodge.

JH: I'm the Executive Director at the Center for Energy and Environmental Policy Research here at MIT, as well as the Research Director for the MIT Climate Policy Center.

LHF: Mr. Hodge is here to talk about upgrading our transmission system. Basically, that means building more and better power lines in the right places. And there are at least three big reasons to do that: to make our power more reliable; cleaner; and cheaper.

But first, we have to explain what, exactly, transmission does. Because we usually focus on how electricity is made—say, by a coal plant, or a wind turbine—or what it’s used for, like in our homes and businesses. Mr. Hodge is going to call these “generation” and “load.”

The transmission connects the generation to the load. And those power lines outside my window? They’re just the last stop on the way. More important are the high-voltage transmission lines that you might see along the highway, strung from giant steel towers, and served by an immense network of machines that direct and convert electricity over hundreds of miles.

And all of that equipment—plus the power plants themselves—need to work together to perform a remarkable balancing act.

JH: To ensure continuous power, to ensure what we call reliability, total generation on the network must be continuously and precisely matched with load. If it’s not, you risk outages and blackouts.

LHF: You know how, if you try to force too much water through a hose, it just spurts everywhere? Well, generating too much power means the electricity has nowhere to go—and that can cause problems. It’s the job of transmission to make sure that we always have exactly as much power as we need: no more and no less.

JH: People don't realize that we have transmission lines tripped all the time, but they almost never result in a blackout. Well, that's because these systems automatically disconnect from the grid when that happens. And they have to isolate those faults in milliseconds.

LHF: A bigger grid means you have more options to reroute power when something goes wrong. That's why upgrading our transmission system gets us more reliable power. And as cyberattacks become a bigger threat to our energy system, and climate change brings more big storms and wildfires that can wreck power lines, we have more reason than ever to brace for the unexpected.

JH: And reliability requires that all parts of the system operate as a single machine, from the generation plants on one end, to the load on the other, and all the equipment in between.

LHF: A single machine that is so large that it crosses states and even countries. A machine in which our power plants are just tiny cogs. And it’s a thinking machine that’s constantly solving thousands of problems, just so you can turn on your dishwasher.

JH: It's quite sophisticated, and I think generally underappreciated.

So it's really good at supplying power for the early-20th-century American economy—I mean, exceptionally good at it. So it efficiently moves electricity from large, centralized power plants like coal, nuclear, and gas plants, to urban industrial centers or centers of load.

LHF: But today, our economy is looking less and less like that 20th-century model. For one thing, our electricity needs are growing—fast. Take the rise of AI, which needs big, energy-hungry data centers.

JH: That is significant potential new load that many regions don't have the capacity to accommodate.

LHF: And at the same time, more people are switching from fossil fuels to electricity to heat their homes and to power their cars. Now, that’s good for the climate, and for our wallets—but it adds even more to the load.

And the new power that we’re building to meet this demand? Well, in 2024, more than 70% of it came from wind and solar. That is very different from traditional coal and gas and nuclear power, which can be built right next to where it’s needed.

JH: So, you know, most of our wind generation in the U.S. is in the central U.S., not necessarily close to even the load centers in those regions, let alone other regions. Our best solar is in the southwest, pretty far from every load center except the big cities in the southwest. But we lack the transmission capacity to deliver that high-quality renewable generation to where it's needed.

And so, you know, the bigger the transmission system, the more diverse wind and solar resources you have access to, the stronger likelihood you have access to electrons somewhere where the wind's blowing, and somewhere where it's not cloudy.

LHF: This is why a bigger transmission system can give us cleaner energy. We can build as much wind and solar power as we want, but if we can’t get that energy to where it’s used, we’re still going to have to fire up our coal and gas plants to keep the lights on.

In fact, if a solar and wind farm can’t deliver electricity to where it’s needed, it shuts down. This is what energy experts call “curtailment.”

JH: There is a utility in Missouri that I work with that has a lot of wind generation in the northwest corner of the state, and they're continuously curtailing it. I think it's almost just a nuisance for them. Because, again, I mean, if the wind was blowing during a peak time, and/or the wind was close enough to the load center, then you'd be using it.

LHF: And this gets at why building out transmission can make our power cheaper. Because the larger the grid, the more easily it can pull from the cheapest sources of electricity—whatever and wherever they may be.

Today, the cheapest power is often wind and solar—at least, when we can get it. But even when our power comes from coal and gas, more transmission helps us get cheaper electricity from these sources. And this flexibility is especially important when the power is most expensive.

JH: So think, you know, big cities during heat waves or big cities during snow storms, right? Prices get very, very high. By expanding one's transmission system, you can access more sources of generation, and indeed, in many cases, lower-cost forms of generation, which in turn enable lower retail power prices.

LHF: So as a country, we must be in a big hurry to build more transmission, right?

JH: So it turns out that, irrespective of how people feel about climate change, they're very reluctant to have any energy-related infrastructure built near them, whether those are solar panels or wind turbines, certainly high-voltage transmission lines.

LHF: Let’s give you an example of what’s happening now, in 2025, in the northeast.

JH: There's New England Clean Energy Connect under construction right now in Maine to bring hydropower from Quebec into Massachusetts.

LHF: This is a good deal for the places at either end. Massachusetts wants more clean power sources like hydro, and Quebec has more than they can use.

But most of the power lines are being built in… Maine, the state in between.

JH: Local and rural lawmakers, even if they support energy development, they may oppose running lines through their districts if the local benefits aren't clear. And that is something that we see frequently with new transmission projects. Siting and permitting is mostly state-level, which means crossing multiple states can require permits and approval from each other. Local opposition, such as environmental concerns, land use disputes, can delay or kill projects.

And, you know, I had a front-row seat to all this in Maine, because I co-authored a paper on this topic. And a lot of people were really upset that our paper showed this line as reducing the cost of decarbonization in New England, because, from their perspective, cutting down trees to build a transmission line inherently hurt the Earth. So they would say things to me like, “What you're saying doesn't make sense. You can't save the Earth by destroying it.”

New England Clean Energy Connect was permitted years ago, they were legally allowed to build it. But it was delayed by years, by lawsuits.

LHF: This is… complicated. The people filing those lawsuits were looking out for their state—the towns and the forests that the transmission lines are passing through. That’s more important to them than getting clean electricity to a different state.

So, whose job is it to look out for the transmission system as a whole?

JH: You know, a key challenge here is no single entity can mandate or centrally fund long-distance transmission. It's pieced together regionally.

LHF: Even though transmission has to work as a single machine, no one’s in charge of building or running the whole thing. And when lots of utilities and grid operators are each looking out for their own areas, none of them are motivated to fight or pay for new power lines.

More often, we build new transmission when the system is on the verge of breaking: when we’ve got a backlog of new power waiting to come online, or a new batch of AI data centers straining the grid.

JH: We're reactive. Reactive, reactive, reactive. In fact, “reactive” is probably being too gentle, because we're reactive, you know, many years after, in many cases, the generation is ready to be connected. Right now, we have thousands of projects, mostly wind and solar, waiting to connect to the grid, but they can't because they're stuck, because there's not enough transmission capacity.

LHF: Yeah, right now, developers build wind and solar where it’s easiest and cheapest, not necessarily where the lines exist to carry that power. But what if we planned ahead for this? What if we made sure, wherever energy is cheapest, the transmission is waiting to meet it?

JH: A positive example of what can be done is the Competitive Renewable Energy Zones in Texas, called Texas CREZ.

LHF: CREZ was dreamed up in the mid-2000s, when there was hardly any wind or solar power in the United States. But Texas lawmakers noticed that windy West Texas had a ton of energy potential. So they put out a call for big transmission lines leading out to this region—even before there was anything for them to connect to.

JH: So it was completed over a decade ago, and it was essentially built so that wind generation in Texas was economically feasible. Texas leads the U.S. in wind production—it's got over 40,000 megawatts of installed capacity now, which is, like, over four Massachusetts’ worth of power, and the whole reason that is the case in Texas is because they were able to come up with a pretty diverse coalition that got something very ambitious built.

LHF: If this has worked for Texas wind, can it work across the United States as well? After all, the U.S. has built big, continent-spanning projects before. Take the railways or our highway network, both of which wouldn’t have been possible without a big push from the federal government.

JH: You know, we did it with the interstate system. It's probably the best precedent we have. And there, the federal government did a very good job of convincing the states of the economic benefits of enabling, facilitating this interstate buildout.

I think an interregional grid across North America enables us to imagine things like sun electrons from Arizona going to Seattle on a cloudy day, offshore wind electrons in Massachusetts enabling Quebec not to have to use its hydro when the wind’s really blowing like crazy here and it's super cheap. And then when the wind's not blowing here, you can bring the hydro down from Quebec.

And, you know, because there are so many economic benefits of expanding transmission, I would love to figure out some way to build stronger bipartisan understanding and, “Hey, we may not agree on how we're going to power this system entirely, right, but we're all interested in a more flexible, more reliable, but, most importantly, a cheaper power system.”

LHF: That’s our show. But there is plenty more Today I Learned: Climate at tilclimate.mit.edu.

I have some important news to share today: This season is my last as the host of TILclimate. It has been an incredible joy and a true privilege bringing this show to you all for the past 60 episodes, and I can only hope that you’ve learned as much as I have, and had half as much fun learning it. But this won’t be the last time that you hear my voice: We are planning some bonus content to round out my time here, and also to introduce our new host, because TILclimate is not going anywhere. So please stay tuned to our feed for more.

TILclimate is the climate change podcast of the Massachusetts Institute of Technology. Aaron Krol is our Writer and Executive Producer. David Lishansky is our Sound Editor and Producer. Michelle Harris is our fact-checker. Madison Goldberg is our Associate Producer. The music is by Blue Dot Sessions. And I’m your Host and Senior Editor, Laur Hesse Fisher. 

Thank you to Joshua Hodge for speaking with us, and to all of you, for listening.