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A podcast by GBH News reporter Ian Coss gives this notorious project a long-overdue reappraisal. Bonus: The show comes with lessons for climate infrastructure projects of the future.

If you’ve lived in Massachusetts at any point in the last 50 years, you’ve heard of the Big Dig. It’s infamous — a tunnel project that was supposed to bury an elevated highway in Boston to the tune of $2 billion that eventually ballooned in cost to $15 billion and took a quarter of a century to finish.
The Big Dig was more than just a highway project, though. It was a monumental effort that Ian Coss, a reporter at GBH News, calls a “renovation of downtown Boston.” The project built tunnels and bridges, yes, but it also created parks, public spaces, and mass transit options that transformed the city. In a nine-episode podcast series appropriately called The Big Dig, Coss dives into the long, complicated history of the project, making a case for why the Big Dig was so much more than the boondoggle people think it was.
I talked to Coss about how the Big Dig came to be and the lessons we can learn from it as we continue to adapt our built environment to a changing climate. Our interview has been edited for length and clarity.
I moved to Boston for college in 2010, and I remember going to the North End and being struck by how beautiful it was. I didn’t realize how recently that view had changed until I listened to your podcast — I mean, the Big Dig had only wrapped up a few years earlier.
It’s easy to forget how quickly it transformed. I grew up in Massachusetts, so when I would come into the city I would see [the Big Dig] being built — I have vague memories of the elevated artery. And when I moved to Boston Proper in 2013, which was less than a decade after the project wrapped, it was stunning for me to be like, “oh, this is what that project was,” because I definitely didn’t understand it at the time.
What made you decide to create an entire podcast about this “renovation” of Boston?
I think part of it was this disconnect where I grew up hearing about the Big Dig and mostly hearing bad things about it — it was behind schedule, it was a disaster, a boondoggle, etc. — because that really was the reputation of the project, nationally and locally. And then moving to the city and seeing the fruits of it, it was hard to reconcile those things. Like, this “disaster” created a greenway through the middle of the city. Now you can actually get to the airport.
What was driving that narrative of its being a disaster?
The Big Dig went on a very long emotional journey. It started as this kind of visionary, idealistic project championed by activists and supported by politicians of both parties. And then, after navigating the process of funding, permitting, contracting, managing, and designing, by the time it's in construction, it really is not a source of pride.
There are a number of technical things about the Big Dig that could have been done better, and we can learn lessons from it. The way it was contracted could have been done better. The management structure could have been done better. There were flaws in the design, including a fatal flaw that cost the life of a driver in the tunnel.
I think a lot of it is about the storytelling. Just to give one example, so much of the negative narrative around the Big Dig was around the cost. You often hear about how it started with an estimated cost of $2 billion and wound up costing $15 billion. But I think that narrative misses a few things.
One is that it was never going to cost $2 billion. That was not a realistic estimate. But in our country, it is so hard to get approval, political support, funding, and permitting in place that there is a very strong incentive all throughout the process to downplay the costs, downplay the risks, downplay the disruption, make it sound like this is going to be quick and easy and painless and cheap, just to get to the starting line. Because the paradox of it is that if we had known in 1983 or 1987 or 1991 that this was going to be a $15 billion project, it would have never happened. And yet, in hindsight, there are many smart people who told me that this project was a bargain at $15 billion because of what we got in terms of economic benefits, transportation improvements, and environmental improvements.
There’s almost an element of asking for forgiveness rather than permission here, but that forgiveness is inevitably laced with anger because of those expectations.
Right. If only it were just forgiveness.
The Big Dig had its roots in the National Highway Program. Were all those projects going constantly over budget?
There’s a great paper that I cite in episode four where the authors studied the cost of highway building per mile every year from the 1970s through the 1990s, and it’s actually a great sample set because we’ve built so many highways of different sizes in different states. Basically, what they found is that highway costs per mile really ramp up significantly in the 1970s. And that’s, of course, the period when the [Big Dig] was first getting conceived.
So the short answer to your question is, it was cheaper once. But there were other costs, in that those early highways in the ‘50s and ‘60s largely did not consider the impact on communities or on the environment. They did not make a lot of mitigation efforts to minimize the day to day disruption caused by those projects. So I think part of what the Big Dig captures is this really historic change in the way we build things in this country that was ushered in by the anti-highway movements, by citizen activism, and by the National Environmental Policy Act. Over the course of the 1970s we made it much harder to build things, for very good reasons.
I think the Big Dig — which some people describe as the last great project of the interstate era — captures an attempt to do a massive, ambitious infrastructure project that is also loaded with environmental mitigation and also has a robust community process. Part of what we learned through that is that you can have a project that’s cheap and efficient, you can have a project that’s democratic and humane, but it’s tough to have it all. And the Big Dig was trying to have it all, and we did get it all, but at enormous cost. That was the thing that could never be solved.
You make a connection between the Big Dig and climate change right from the first episode. What are the climate lessons we can learn from the Big Dig?
In some ways, it’s ironic to hold up the Big Dig as a case study for climate change because it’s a highway project. My point is not that the Big Dig is, like, the future of infrastructure. But what it offers is a recent case study on a massively ambitious building project. We have some distance, and you can see the whole arc of it, but it very much lives within our era. It’s not the Hoover Dam or the Golden Gate Bridge or any of those other big projects built in a different time under different conditions.
The way I see it is that in order to mitigate or prevent the worst effects of climate change — and you can feel free to disagree with me — we’re going to need to build a lot of stuff. This is not a problem that we’re going to solve by riding bicycles and growing vegetables in the backyard, both of which I do and hope everyone does. And of course, those projects might look different than the Big Dig because building a wind turbine isn’t exactly analogous to building a downtown tunnel. But I think there are relevant analogies, especially things like coastal mitigation in cities, improving mass transit, building high energy transmission lines — these large scale projects that will affect people but also are an important public good.
You talked on the show about the Big Dig as an attempt to make this process more democratic at some level. People on both sides had very strong feelings about it. This reminded me of the NIMBY/YIMBY dichotomy of climate projects. Did anyone mention any best practices that could be applied to future projects of this kind?
I’ve talked with Fred Salvucci [former Massachusetts Secretary of Transportation and driving force of the Big Dig] about this. He mentioned this biblical parable — he’s full of parables — about Jesus walking across the water and then turning to his disciples and telling them to follow. But they step into the water and fall right in, and when they get back out they say it’s impossible. And then Jesus says, “It’s easy to walk across the water. You just have to know where the stones are.”
And Fred said the lesson there is that, in order to navigate this kind of process, you have to know where the flashpoints are, what the issues will be. That way you can anticipate them rather than just going in and saying “this is my project, I’m going to do it this way and you can fight me on it.”
Part of what I think is really interesting about this, which I think speaks to present-day projects like offshore wind, is that in that fight, you have very well-intentioned actors who are trying to make the project better and using the environmental process to do that. And you also have bad actors who are weaponizing and manipulating the environmental process to their own personal ends. And those two things get all mixed up.
You know, I’m an environmentalist. I believe in environmental review. I don’t want to sit here and say that we need to get rid of all environmental permitting because it makes it too hard to build things. But I think it’s also important to recognize that these things can be weaponized.
Scheme Z, which proposed this big spiral loop of ramps and a bridge over the river, is a good example. Politically, that became very messy — they were trying to impose concentrated harm in the name of a public good. And I know, strategically, maybe there are things [Salvucci] could have done to mitigate that or circumvent that, but given the structures in place, the logical outcome is that it spends a decade in lawsuits and review committees and you wind up with something that’s okay, that everyone can live with.
The funny thing about that is that it turned into the Zakim Bridge, which is now a Boston icon.
Right. I mean, that’s part of the communication piece, too.
I was biking under the Zakim bridge the other day, and I biked through where there’s a nice pedestrian and bicycle bridge and this skate park that is always filled with people. Truly, that is maybe the best utilized public space created by the Big Dig.
It’s easy for me to play Monday morning quarterback and say “oh, you should have communicated that better, you should have told the story better.” I mean, he was saying all the right things. But then all you had to say on the other side was “it’s 18 lanes and five ramps,” and that sounded terrible and looked terrible on the page. And I mean, sure, I wish there weren’t all those ramps there, but like you said, ironically, the bridge became an icon of the city.
I think a big part of the lesson for me is how hard it is to build infrastructure democratically because the timescales are all wrong. These things have short-term costs and cause short-term disruption and bring very long-term benefits.
I was constantly struck by this issue of scale, both in terms of time and money. It’s hard to wrap your head around the idea of billions of dollars and projects that span decades. These are just things that are impossible for any regular person to really plan out.
I was talking to someone who said that their dad was in his 70s when the Big Dig was just getting started. And for him, it was like, “my city’s going to be torn up for the rest of my life,” right? That’s what this project meant for him — he would live with this mess of a project and never see the results. And he had to deal with that so that you could move to Boston in 2010 and never know the city another way. The cost of that benefit is borne by another generation.
And it’s the same thing with climate change. It moves on a scale that is so much longer than politics. The Big Dig took almost 40 years from conception to completion. So if you’re thinking about political capital, if you’re thinking about two- and four-year election cycles, it’s very, very hard to conceive, plan, and deliver a project on that kind of time scale.
The benefits and costs are almost inverted in climate change, in a way. We’re talking about future benefits, yes, but we’re also talking about future costs if we don’t do anything. But it’s so hard to make people think in a 40- or 50-year timescale.
If the Big Dig was so hard to make happen politically with what I think was a more genial political environment overall, it feels kind of impossible to think of building anything on that scale right now.
I gave a talk at City Hall a few weeks ago and I was talking with some of the young planners there, people who are in their 30s. Some of them have been listening to the series, and they told me they could not imagine what it would be like to get that kind of federal funding out of Washington, get all the local players on board, get it through the permitting process, and get it contracted. Because right now if they try to take away one parking spot and put in one bike line, they’re bogged down in meetings for a year.
I think climate change is also the inverse of projects like this because with the Big Dig, for example, you can feel the tangible benefits of a quicker commute and a more beautiful city. But with climate change, if the projects work, you’d actually feel nothing.
Exactly. Climate change is way, way harder. A road project or a rail project will have benefits. You get ribbon cuttings and photo ops. But if we make Boston resilient to flooding or something, you know, do some big project that would improve the shoreline or whatever ideally, that historic storm surge may never come, or it’ll come and we’ll be prepared for it and nothing will happen. But yeah, you’re working with long term counterfactuals.
It feels to me like climate change was designed in a laboratory to flummox institutions. It takes all of our cognitive biases, our ingrained social and biological blind spots and weak points and just flicks them all at us at once.
All nine episodes of The Big Dig are out now. You can listen on the WGBH website, Apple Podcasts, Spotify, or wherever you get your podcasts.
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BAAJA would likely help speed up the U.S. transmission buildout, but there’s a chance we’re undercounting the benefits.
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As you may have seen, my colleague Emily Pontecorvo and I got the first look at the Rhodium Group’s analysis of what the bipartisan permitting bill will do to emissions.
You can read our story at Heatmap. The upshot is that the bill’s most significant provisions are likely neutral for climate change in a worst-case scenario — and could, in more optimistic scenarios, help reduce emissions. (Those scenarios aren’t about how the bill will be interpreted, to be clear, but about what might happen in the broader energy economy — with economic growth, for instance, or oil prices — that will feed back into the emissions math.)
I won’t give away much more about our story, but there is one irony I want to note about the Rhodium study and the broader morass of American electricity policy. One of the Rhodium study’s big findings is that BAAJA will help expand the transmission system. Power lines are essential for decarbonization because they move electricity from the country’s sunniest and windiest places to its cities, towns, and suburbs.
BAAJA will help transmission both because the law affirmatively expands the power grid and because the bill’s changes to environmental review law could help power lines. Today, for instance, it takes twice as long on average to conduct a federal environmental impact study for transmission lines as it does for pipelines, according to Rhodium data. All in all, the Rhodium analysis estimates BAAJA could increase the amount of new transmission capacity added per year by 167% to 262% nationwide, compared to the average rate over the past decade.
Which is very interesting. But it’s worth noting that the Rhodium analysis may — emphasis on may — undercount the bill’s transmission benefits. This is because the Rhodium authors did not have time to conduct a full network study of the U.S. transmission system, which would take into effect the grid’s physical footprint, power flows, and existing bottlenecks. Instead, they looked at power supply and demand within the context of the broader U.S. energy system.
That’s a reasonable decision; indeed, it was probably the only decision they could make. Because of how energy system models work, a more fulsome analysis might have taken weeks to complete, not to mention a very large amount of money and computational power. When the National Renewable Energy Lab studied how quickly Los Angeles could switch to 100% renewable energy earlier this decade, for instance, it ran such a study, modeling every transmission line and substation in LA. Its supercomputer wound up churning through more than 100 million simulations; the research effort took three years. If the Rhodium analysts had done even a fraction as much work to examine what BAAJA would mean for the country’s power grid, then they would have of course finished their analysis well after the window to vote on BAAJA would have closed.
One of the ironies here is that while the LA 100 study was particularly exhaustive, we actually require clean energy projects to conduct similar studies all the time. Right now, one of the primary reasons it takes so long to hook up a new power plant to the grid is that it has to undergo an interconnection study in many parts of the country. In those regions, a new solar farm or battery project can’t connect to the grid until operators study its effect on grid congestion everywhere else.
As it happens, BAAJA aims to fix this process, allowing power plants to join the grid in batches.
I want to note the irony that a process we mandate for the power sector is actually too slow to deliver speedy policy analysis to legislators. If Rhodium had tried to study BAAJA the way we make power plants study the grid, then it never would have delivered its verdict in time. If you think Congress is slow, in other words, you should meet the electricity sector.
Current conditions: The Pineapple Express, an atmospheric river originating in the Pacific near Hawaii, is arriving in the Southwest laden with heavy rain that’s set to flood the region • Indonesia has the worst air quality in the world as forest fires rage along Sumatra’s southern coast • A cross-country storm will soak much of the United States on Tuesday’s Election Day.
The Senate’s grand compromise to simplify federal permitting on energy projects would likely drop emissions slightly as the benefits to accelerating deployments of clean energy infrastructure outweigh the boost the legislation could give to fossil fuels. Even under the worst-case scenario, emissions remain on the same trajectory as today. That’s according to a hotly anticipated new analysis by the Rhodium Group, the consultancy whose U.S. emissions estimates are among the most widely cited in American politics. The report, shared first with my colleague Emily Pontecorvo, found that provisions in the Bipartisan American Affordability and Jobs Act largely counteract each other on climate. The bill makes building transmission lines much easier, a key step to patching more renewables onto the grid. But it also makes new gas pipelines simpler to permit, clearing the way for a buildout of the infrastructure for the fossil fuel already dominating U.S. electricity and heating systems. Still, under the best-case scenario, the legislation could cut U.S. economy-wide emissions by 5% below where they would otherwise go in 2040. The bill could also slash energy bills by $78 per year and support construction of more than 200 gigawatts of clean energy capacity, as compared to a world where it didn’t pass. The Rhodium report is at least the second analysis yet to find that the bill could modestly lower emissions. The first, as I reported last week, came from the think tank Resources for the Future, which saw a slight drop in power-sector emissions relative to a world without BAAJA.
If overhauling national permitting rules to make building green energy infrastructure easier doesn’t work to lower emissions, traditional negotiations in favor of regulations that can deliver cuts looks no more promising. Two weeks of United Nations-led talks in Armenia ended Saturday without a settled approach to meeting 2030 deadlines for preserving more nature. “We don’t need to spend more to close the biodiversity funding gap, we need to spend better,” Marina Von Weissenberg, a Finnish senior ministerial advisor, said in a statement. “Governments have a real opportunity here to reshape public spending with future generations in mind, but they can’t do it alone. International coordination is key to giving governments the confidence to lead change.”
Last week, my colleague Katie Brigham published a detailed feature highlighting China’s tightening grip over the global supply chain for electrolyzers, the technology that zaps water with electricity to separate the molecule’s hydrogen from its oxygen and harvest the former as fuel. Keen readers of this newsletter recognize the story. Even before the Iran War, China had beefed up its public support for green hydrogen and related technologies. After the conflict constricted the flow of oil through the Strait of Hormuz, the People’s Republic redoubled its efforts. Quite literally. New data from the National Energy Administration shows that investments into the hydrogen industry doubled in the first nine months of this year, according to Hydrogen Insight.
Fermi America went public in a gangbusters initial public offering last year as the company, with a board of directors including former Texas governor and U.S. Secretary of Energy Rick Perry, pledged to build the world’s largest data center and power the facility with gas and four large-scale Westinghouse AP1000 nuclear reactors. In April, the chief executive and chief financial officer quit. The board room drama continued into the next month. The company’s stock recovered somewhat over the summer as investors bet on a turnaround pegged to a series of deals with companies looking to lease space on its future servers. But fresh chaos enveloped the startup Friday when The Texas Tribune reported that Perry had failed to earn enough support from the board of directors to win reelection to his seat.
In a statement posted to X on Friday evening, Fermi said that neither Perry nor investor Jeffrey Stein had been removed from the company’s board. “In fact, both Governor Perry and Jeffrey Stein received a majority of the votes cast by shareholders,” the statement read. “Let’s be clear: Governor Perry and Mr. Stein remain members of Fermi’s Board of Directors and will continue serving until their successors are duly elected. Both remain eligible for reelection.”
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If you thought the fine particulate matter from last year’s catastrophic Los Angeles firestorm was bad, you weren’t thinking imaginatively enough about just how dangerous all that airborne material could be. A new study published in the journal Science Advances suggests that upward of 7 million people were exposed to high levels of airborne lead and other toxic metals released when homes and vehicles caught flame. The January 2025 Eaton inferno that destroyed more than 9,400 buildings and killed 19 people spewed 80 times the normal concentration of lead found in the atmosphere through a plume that settled over 70% of the Los Angeles metropolitan area. “I can envision that in the future we have these evacuation zones for smoke exposure as well,” Haroula Baliaka, the study’s lead author, who was a PhD candidate at Caltech last year, told Bloomberg. “Unfortunately, this is not a one-time event. It’s a new reality and we need to adapt to it and we need to do it sooner rather than later.”
The findings come a week after a study published in JAMA Pediatrics showed a link between wildfire smoke exposure during pregnancy and autism diagnoses in children. The research from Rutgers University examined 893,212 mother-child pairs enrolled in Medicaid, with children born between 2007 and 2014. Each increase of 0.75 micrograms per cubic meter in average concentrations of wildfire-related air pollution during pregnancy was associated with a 30% higher risk of a subsequent autism diagnosis. Exposure in the second and third trimesters had the highest risk. “Wildfire smoke can travel far beyond the communities where fires are burning, and exposure may occur even when smoke is not visible,” Stefania Papatheodorou, an epidemiologist at the Rutgers School of Public Health and lead author of the study, said in a press release. “Our findings highlight the importance of awareness of wildfire events and their potential effects on air quality during pregnancy.”
The United Kingdom is building out more than 10 gigawatts of offshore wind as London looks to shore up its electricity supplies amid the global energy shock. But Chancellor of the Exchequer John Healey said he would veto any offshore wind projects that don’t lower bills. While clean power is “how we break the grip of international gas prices on our bills,” he said the infrastructure “has to come at the right pace, in the right places, with the grid to carry it.” The statement fueled what The Guardian called “concerns that the government is moving away from the pro-renewables agenda.”
Meanwhile, the U.S. midterms aren’t the only election this week. In Sunday’s runoff election, Bulgaria’s pro-Russian acting President Iliana Iotova appeared to eke out a victory over the former prime minister Andrei Gyurov, a pro-Western banker. Her win unites the government with her close ally, Prime Minister Rumen Radev, ensuring stronger support for the leader’s two signature energy policies. One, a plan to build a pair of Westinghouse AP1000s at the Kozloduy nuclear plant, is scheduled to advance to the next planning stage next year. The other, the easing of sanctions on Russian uranium to ensure a supply of fuel for the plant’s existing reactors, looks likely to continue under Iotova’s friendly diplomacy with the Kremlin.
William Nordhaus, the pioneering Yale University economist who won the Nobel Prize in 2018 for integrating climate change into macroeconomic analysis, has died at 85 following a battle with an aggressive form of brain cancer. His nephew, Ted Nordhaus of the Breakthrough Institute, referred to his father, Robert Nordhaus, as “the original environmental lawyer and Bill as the original environmental economist,” he wrote in a blog post after his uncle’s passing. “It is safe to say that the Nordhaus brothers were doing environmental law and economics, respectively, long before either label existed. Not bad for two kids who grew up in the intellectual hotbed of Albuquerque, New Mexico, population 40,000, during and after the second world war.” Their legacies are something of the Nordhaus family brand: Pragmatism. May his memory be a blessing.
Even in the worst-case scenario, BAAJA wouldn’t increase emissions, an analysis by the Rhodium Group concludes.
The bipartisan permitting reform bill is likely to slightly cut greenhouse gas emissions and lower electricity bills by 2040 — or at worst leave emissions on the same trajectory that they are on today — as compared to the status quo, according to a new analysis of many of its provisions by the Rhodium Group, an independent research firm.
The analysis examines the policies in the Bipartisan American Affordability and Jobs Act, or BAAJA, that would have the most-clear cut effects on climate pollution and the energy system. It is the most comprehensive account of the bill’s effects on emissions so far, although it does not examine all of its provisions.
The bill is hard to analyze because — unlike recent partisan energy bills, such as the Inflation Reduction Act or President Trump’s tax and spending bill — its effects on the climate are more ambiguous and often seem to counteract each other. BAAJA will make it easier to build not only long-distance transmission lines, which are essential for clean energy, but also natural gas pipelines, which can expand fossil fuel production.
Yet the climate benefits likely outweigh or balance out the harms, at least among the studied policies, the report finds. In the best case scenario, the bill could cut U.S. economy-wide emissions by 4%, reduce energy bills by $78 per year, and drive more than 200 gigawatts of new clean energy capacity by 2040, compared to status quo policy. In a worst case scenario, greenhouse gas emissions would remain unchanged on their current trajectory.
The results should be viewed as more directionally instructive than a precise accounting of the legislation, Ben King, an energy and climate director at Rhodium, told me.
“We don’t see emissions increasing because of the bill,” King said. “This bill should drive some emission reductions, it should drive some more clean energy on the grid, and it should drive electricity bills down. And given the complexity of the bill, that’s what we can say at this point.”
The analysis does not look at the bill’s permitting certainty provisions, which Democrats initially sought to stop President Trump’s war on wind but have become one of its thorniest sections. Rhodium’s modeling is also a crude tool for assessing transmission policy, since the model can look only at economic inputs such as supply and demand, and not the physical reality of the U.S. grid, such as where transmission lines run or where the bottlenecks are.
It is the second analysis to find that the bill could modestly lower carbon pollution. A more limited report focusing only on the power grid, published last week by the think tank Resources for the Future, found the legislation could cut electricity emissions by 6% while reducing electricity system costs by $350 billion through 2050.
The effects of the bill may sound small, but BAAJA is not a climate bill. It’s not engineered to reduce reliance on fossil fuels or boost clean energy technologies. Its overarching purpose is to address various federal bottlenecks that bog down America’s ability to build stuff, whether that’s a pipeline or a highway or a power line or a solar farm. So it’s not entirely surprising that it’s not expected to have a dramatic effect on emissions.
The reason it’s a priority for Senate climate champions is that many of its provisions are important precursors to decarbonizing the U.S. economy more quickly. By enabling faster expansion of the power grid, the bill would put the country in a much better position to transition to clean energy. After Joe Biden’s big climate bill, the Inflation Reduction Act, passed in 2022, Princeton University researchers found that the country’s slow buildout of transmission lines would be a major obstacle to gleaning the law’s benefits. Unless the country more than doubled the rate of transmission expansion, they wrote, more than 80% of the IRA’s emission reduction potential by 2030 would be lost.
BAAJA could nearly triple the build rate of high-voltage transmission, the Rhodium Group found, from an average of about 0.7 terawatt-miles added per year over the past decade to an average annual pace of 1.9 to 2.6 terawatt-miles through 2040. Because Republicans and President Trump have repealed so many of the IRA’s provisions, this won’t drive as much clean energy as the Princeton researchers expected, but Rhodium estimates that by 2040, BAAJA would help between 17 and 249 gigawatts of clean resources get built compared to a world without it.
The growing grid is the main reason why the bill cuts energy costs, because it enables more lower-cost resources to connect to the grid. The bill’s requirement that data centers pay the full cost of connecting to the grid also puts downward pressure on electricity rates.
“If your goal is to do climate policy in the future, this is an important down payment to making progress there,” King said.
The authors studied the bill’s provisions under a range of economic assumptions, including a “best case” scenario in which clean energy gets cheaper and easily outcompetes natural gas, and a “worst case” scenario where natural gas prices collapse and the inexpensive fuel keeps dominating the U.S. energy system.

The authors limited their analysis to the bill’s provisions that speed up transmission line and natural gas pipeline permitting. They assumed that when you make it easier to approve transmission lines, the lines get cheaper to build and get built more quickly. The same goes for gas pipelines. Then they looked at how the energy system would respond. Would we build more power plants? Would there be more natural gas production? Where will that gas go?
The caveats, aside from omitting the bill’s “project certainty” provisions, are that they did not account for policies that support geothermal energy, virtual power plants, advanced transmission technologies, or the ways in which the bill would reduce congestion on the grid — all of which could result in fewer emissions. At the same time, the modeling assumes that all of the data centers that get built between now and 2040 connect to the grid, even though today, many data centers are planning to run on inefficient off-grid natural gas plants. That means this modeling likely underestimates emissions from data centers. (Although the authors did a separate exercise that went deeper into data centers, which I’ll explain shortly.)
The report also limited its analysis to the United States. While the modeling found that liquified natural gas exports would increase by 8% to 15% under BAAJA, the authors did not account for how those exports could affect the energy mix or emissions in the rest of the world.
They found that the bill’s changes to the Clean Water Act and the National Environmental Policy Act would enable more gas pipeline development, which, in isolation, would increase emissions relative to a world without BAAJA. More pipelines means more production of oil and natural gas, which means higher methane and CO2 emissions throughout the fossil supply chain. Under a worst case scenario, they estimate a 4% increase in the amount of new gas capacity, although gas-fired generation as a whole increases by less than 1% in 2040. Even then, emissions would simply be flat compared to current expectations.
“On net, the emissions increases that we see there are outweighed by the emissions benefits that come from the transmission provisions of the bill,” King said.
The report also studied how BAAJA might affect data center emissions. Its “base case” scenario — which includes all the analysis I’ve shared with you so far — assumes data centers will make up about 17% of electricity demand by 2040. That figure already supposes huge growth in data center energy consumption, because data centers only use about 5% of U.S. electricity today.
But what if data center demand grows even faster than that? The authors modeled two additional scenarios to see what would happen if data center electricity demand instead accounted for more than a quarter of U.S. electricity demand in 2040.
While BAAJA would make it easier for data centers to connect to the grid, it also includes ratepayer protection provisions that would make it more expensive to do so — roughly 10% more for a 1 gigawatt data center, Rhodium estimates. Determining whether that will drive developers on-grid or off-grid was beyond the scope of the analysis, so the modelers looked at the two extremes — a world where all additional data center demand hooks up to the grid and one where none of it does.
For the on-grid scenario, whether or not that additional demand is met with mostly gas plants or cleaner sources largely depends on the price of fossil versus clean generation. But even if most of the demand was met by natural gas plants on the grid, emissions would still be 30% lower than if it was met by natural gas plants off the grid, Rhodium found.
Editor’s note: This article originally misstated the scope and timing of electricity systems savings in the Resources for the Future study. It has been corrected in this version.