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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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Average U.S. gasoline prices have slipped back above $4 a gallon.
A decade ago, the Princeton economists Alan Blinder and Mark Watson published a paper about a fact that they called “not nearly as widely known as it should be”: The U.S. economy has done better under Democratic presidents than Republican presidents.
Blinder was not a completely impartial observer — he served on President Bill Clinton’s Council of Economic Advisers, and Clinton later appointed him vice chair of the Federal Reserve — but he and Watson compiled a lengthy list of statistics to back up their claim. The U.S. economy has grown faster, produced more jobs, had a lower unemployment rate, seen higher corporate profits and investment, and experienced better stock market performance under Democrats than Republicans. While the original paper described this divergence from 1947 to 2013, recent research has shown that it held through the subsequent Obama, Trump, and Biden administrations.
The only metric where the two parties come close is inflation, but Democrats still seem to have a tiny edge there, even after the Biden-era inflation.
Why? Blinder and Watson found that it didn’t entirely come down to timing. (Other observers have disputed this, arguing that Republicans tend to get elected at the peak of economic booms, while Democrats win during or just after recessions.) Instead, Blinder and Watson found that a few factors — oil shocks, productivity growth, a more favorable international growth environment, and perhaps better consumer confidence — could explain much of the divergence.
Of course, these factors can’t be entirely separated from a president’s record in office. Oil shocks, for example, tend to drag down global growth, which in turn slows the U.S. economy. And as Watson and Blinder write, some of those oil shocks “may have been induced by [American] foreign policy.” By that mechanism, presidential bellicosity in the Middle East can translate into poorer economic outcomes. This belligerence may even be, as the writer Matt Yglesias contended earlier this year, Republican presidents’ “worst economic policy.”
Why am I recounting all this? Because average U.S. gasoline prices have slipped back above $4 a gallon, according to AAA. (As I write, they stand at $4.01.) The collapse of the ceasefire with Iran — and President Trump’s inability to figure out how to end a war he started — are once again driving up fossil fuel prices.
The numbers add up. Defense Secretary Pete Hegseth told Congress today that the Iran War has cost $37.5 billion so far, but according to a tracker from Brown University researchers, Americans have already paid nearly double that — $71 billion! — on more expensive gasoline and diesel fuel. A billion here, a billion there, and pretty soon you’re talking about real economic underperformance. That estimate suggests the burden of higher energy prices from the Iran War has wiped out the expected $65 billion consumer boost from the One Big Beautiful Bill Act’s expanded tax refunds.
Of course, from a decarbonization perspective, higher gas prices are good, in theory. They encourage people to drive less and to switch to more fuel-efficient — or even fully electrified — vehicles, reducing carbon emissions. (This is part of why I joke about Degrowth Donald, raising fuel prices as he goes.) But short-term oil shocks are the second worst kind of emissions reductions after recessions: They are unlikely to last; they will probably not lead to real decarbonization; and they produce a lot of human misery along the way.
Perhaps this oil spike won’t persist. Perhaps Trump will find a way out of the quagmiring conflict in the Persian Gulf. Perhaps Republican presidential underperformance really does all come down to luck, too. (Or maybe, as a 2020 paper argued, Democratic presidents benefit from a “pre-election growth surge” just before a Republican wins.) But I think it’s worth noting that the recent trickle of news — and the recent and less noticed surge in gas prices — is how an oil interruption results in slower growth overall. If oil shocks really are responsible for GOP presidential underperformance, this is what it would look like.
The irony is that technology finally exists to make the American transportation sector — and the overall economy — less dependent on oil. This technology was developed at the American public’s expense to help manage a scenario much like this one. And the administration has undermined it at almost every opportunity.
The latest forecast from BloombergNEF raises its estimate for AI electricity demand by 83%.
Energy analysts at BloombergNEF predicted last year that U.S. data center electricity demand would reach 106 gigawatts within the next decade. In its latest outlook, released Tuesday, the group increased its forecast by 83%, to 194 gigawatts — enough to light up 150 million homes, or roughly every single household in the country today.
Even that may be a conservative estimate. If data center developers were to max out the total number of the high-powered chips used to train and operate AI models forecast to be delivered by 2035, electricity demand would reach 229 gigawatts.
Over 100 gigawatts of that demand has entered the development pipeline since the beginning of this year, the result of both rising demand for artificial intelligence and shortened construction timelines for data centers. Some developers have oriented their site selection around energy availability, redeveloping brownfield energy generation sites for quick access to electricity and developing relationships with utilities. Others have eschewed grid interconnection entirely and instead relied behind-the-meter power generation.
As Mark Daly, head of technology and innovation at BNEF and a co-author of the report, pointed out to me, a growing share of the project pipeline comes from first-time developers. He and his colleagues project that non-hyperscaler data center capacity will nearly quintuple over the next decade, as hyperscaler capacity almost triples. That could ultimately create pipeline risks, however, as small-scale developers lack the capabilities of more experienced developers to optimize around pre-construction bottlenecks and navigate rapidly growing local opposition. Although local opposition to data centers has become prevalent, historic trends and predictions on how quickly developers are able to navigate hostile environments are built on the proficiency of experienced developers. Because first-time developers may face more challenges, Daly told me that data center projects overall “would see an increase in the number of delays.”
All of this, of course, comes with a big asterisk. The data center sector is rapidly evolving, and therefore highly uncertain. Among leading market research firms, BNEF said, there is a 100-gigawatt spread between the lowest and highest predicted electricity demand from data centers in 2030. Driving this spread are differences in assumptions about the average development timeline for a data center project. Daly told me that BNEF’s “project-based estimate is middle-of-the-road to bearish compared to other outlooks,” but also acknowledged that the fickle nature of local opposition on development timelines may place more constraints on future data center development than currently modeled.
No matter which prediction turns out to be most accurate, hourly U.S. electricity demand will come under intensifying pressure. BNEF predicts that average hourly U.S. electricity demand from AI workloads will grow five-fold over next nine years, reaching 120 gigawatts by 2035. That will put data centers at 12% of total electricity consumption on average by 2030, and 20% in 2035, up from 5% in 2025, according to figures from the International Energy Agency. This will put particular strain on electricity prices in markets like the Mid-Atlantic’s PJM, where data centers already comprise nearly a third of electricity consumption, and Texas’ ERCOT, where data centers currently consume a fifth of the market’s electricity.
Even the most conservative bet on future data center electricity demand is a scenario we’re not prepared for. If the Electric Power Research Institute’s prediction that just 56 gigawatts of new data center capacity will be up and running by 2030 — the lowest estimate BNEF cited — that would still consume the equivalent of Sweden’s total energy supply. Absent investments from utilities into grid resilience and intensive permitting reform to speed up renewable energy siting and development, PJM and ERCOT customers will not be the only ones feeling a serious squeeze in their wallets when their monthly utility bills arrive.
Current conditions: Tropical Depression Two strengthened into Tropical Storm Bertha yesterday, recycling the name of the 1996 Atlantic hurricane season’s first major storm • Floods from the monsoon season killed at least four people in Vietnam and left as many missing • Lightning in Utah sparked the state’s latest wildfire, the Meeks Fire, near the Strawberry Reservoir.
President Donald Trump’s on-again, off-again feud with America’s northern neighbor is, as of Monday, back on again. The White House imposed 50% tariffs on most Canadian goods, accusing the nation’s geographically nearest ally and closest cultural bedfellow of unfairly discriminating against American automotives, alcohol, and dairy products. The move threatens to unleash what the Associated Press called “a new wave of economic chaos, with risks of higher inflation and further fraying of relations between two nations that had been closely woven together before Trump’s return” to office.
In its announcement, the Trump administration said the new tariffs would “apply to all covered goods regardless of whether a good originates under the U.S.-Mexico-Canada Agreement,” referring to the Trump-negotiated North American free trade agreement, which the U.S. opted this month not to renew. This struck my colleague Robinson Meyer as ominous. “If the White House now thinks it can levy taxes despite that pact,” he wrote in yesterday’s Heatmap Daily newsletter, “then the risks for Ford, General Motors, and their suppliers have increased.”
Perhaps the only thing growing faster than voters’ antipathy toward data centers is the market’s desire for more of them. Demand for data centers is ballooning at such a rapid clip that BloombergNEF just raised its total forecast for 2035 by a jaw-dropping 83%. The latest data outlining the best-case scenario from the energy consultancy, released Tuesday morning, shows the total installed capacity of U.S. data centers reaching 194 gigawatts in the next nine years. The surge reflects how quickly new server farms are flowing into the project pipeline. In a bid to hedge against the continued expansion, BNEF created a new scenario based on the implied power demand of forecast shipments of microchips for AI computers up to 2033. This scenario implies an even greater need for power: 229 gigawatts of demand from data centers in just the next seven years. And that doesn’t count the continued growth of demand from data centers carrying out non-AI functions, such as traditional cloud computing workloads. This comes as the latest Heatmap Pro polling shows that seven in 10 Americans now oppose data centers in their backyard, a marked shift from last September, when the same survey showed voters evenly split in support and opposition.
That ballooning demand is already showing up in power markets. Of the $16.4 billion in charges from PJM Interconnection’s most recent capacity auction, $6.3 billion — some 38% — stems from data centers. That’s what Joseph Bowring, president of PJM’s independent market monitor Monitoring Analytics, told Utility Dive last week. In the last four base capacity auctions the nation’s largest grid operator held, 46% of capacity charges were driven by data centers. “PJM is continuing to act like it’s business as usual,” Bowring told the trade publication Friday. “You have to open your eyes and recognize that it is really a paradigm shift, and failing to do that imposes costs on other customers.”

On a logical level, it’s a simple supply and demand problem. The supply of electricity is not growing as quickly as demand, all while the Trump administration eliminates subsidies that once buoyed investments in new supply. As a result, corporate electricity deals look poised to increase in price. But not for every generating source. New estimates from LevelTen, a marketplace for power purchase agreements, found that solar PPAs were 5% cheaper in the second quarter of this year compared to the first quarter. In a piece by my colleague Matthew Zeitlin, LevelTen attributed the decline to an especially steep drop in prices in California’s electricity market. Excluding CAISO, solar PPA prices nationwide dropped slightly less than 2%. While hyperscalers are still buying solar, LevelTen found that commercial and industrial buyers are pulling back, creating a “continued softening in the market’s buy-side.” “We saw a lot less corporate energy buyers in the space in 2025 — 40% less — and that is just due to the increase of hyperscalers and data centers getting projects and snapping them up quickly,” Sarah Wolf, LevelTen’s director of North American transactions, told Matthew.
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Ah, Germany. The land of the Autobahn. Diesel-powered industry. The purring engines of BMWs, Porsches, and Mercedes-Benzes. The nation’s automotive might makes its latest milestone particularly important: Electric vehicles just outsold gas and diesel cars for the first time. New data from the Federal Motor Transport Authority shows that Germans registered 84,057 new electric vehicles in June, a more than 78% year-over-year increase. Traditional hybrids, meanwhile, saw 83,315 registrations, followed by gasoline-powered cars with 60,796, diesel with 33,862, and plug-in hybrids with 32,212. “The automotive history books will need a new page sooner rather than later, after electric cars outsold every other fuel type in Germany for the first time,” InsideEVs reporter Iulian Dnistran wrote. “It’s a huge shift in Europe’s biggest car market, which has traditionally been associated with diesel-powered cars that could travel hundreds of miles at highway speeds without breaking a sweat.” The Tesla Model Y was by far the best-selling EV in Germany, with nearly twice as many registrations as the No. 2 vehicle, the Volkswagen ID.3.
Putting on my Mesopotamian metal merchant hat again: Copper prices are back up. The price of the metal needed for virtually all electrical infrastructure rose 1.3% to just under $14,000 per metric ton, according to Mining.com. The price ultimately hovered at the red metal’s record set in early June. The spike stems from data showing rising tightness in the Chinese market, namely a hike in the premium buyers will pay in Shanghai for shipments of the metal. The price hiked further after a series of storms halted production in Chile for a few days.
While the West dithers on hydrogen, China is making huge strides. It already may be too late to catch up to Beijing on manufacturing the key machinery needed to produce the zero-carbon fuel. The latest data point, via Hydrogen Insight: China just shipped its largest electrolyzer order yet to Europe, via Romania.