If there’s one climate policy you’re likely to hear about in the debt ceiling deal, it’s the Mountain Valley Pipeline.

The 304-mile pipeline, which will link West Virginia’s booming gas fields to the East Coast and Texas, essentially received automatic approval under the bipartisan deal. The bill compels federal agencies to approve the pipeline and then shields those permits from judicial review, all but guaranteeing the project’s eventual completion.

If nothing else, the deal brings the saga over the Mountain Valley Pipeline to a close almost a year after it began: The White House initially agreed to support the project last year in exchange for Senator Joe Manchin of West Virginia’s support for Biden’s climate law. But neither Manchin nor Biden could get a bill containing the pipeline through Congress last year as part of a larger package of permitting reforms. Manchin persevered, and the pipeline wriggled into the deal over the weekend thanks to House Republicans and oil-and-gas lobbyists. Manchin, it seems, finally has his pipeline.

The project isn’t the most important climate item in the deal. That distinction has to go to the deal’s preservation of the Inflation Reduction Act, which will ensure hundreds of billions of dollars go to clean energy and infrastructure over the next decade. Nor is it the deal’s worst blow to the climate: As I wrote yesterday, Democrats’ failure to secure any power-grid reform takes that title.

Yet the Mountain Valley Pipeline, or MVP, is the item that environmental groups have focused on the most. “Allowing this deal to advance sets a dangerous precedent,” Ben Jealous, the Sierra Club’s executive director, said in a statement. “We can pay America’s bills without undermining bedrock environmental protections or fast tracking the fracked gas Mountain Valley Pipeline.”

So I was curious: How big a deal is the MVP? When completed, it will transmit 2 billion cubic feet of natural gas a day: What does that actually mean for the country’s natural gas transmission?

Well, here’s a potentially helpful chart:

Energy Information Administration/Heatmap

This is the Energy Information Administration’s chart of new natural-gas pipeline capacity from 1995 to 2022 with my addition. I’ve added the MVP’s capacity at the right. As you can see, the MVP alone will add more pipeline capacity than the entire U.S. added last year — but that’s partially because the country added much less capacity in 2022 than it has in any year since records began in 1995.

I’ll be honest that the chart helps me think more clearly about the project, but not in a way that’s easy to describe. The Mountain Valley Pipeline is a medium-largeish pipeline — big enough to single-handedly expand the country’s ability to move natural gas, but not so big that it will change the fundamental trend that fewer new pipelines are getting built every year.

The MVP’s most important effect may not be its size, but its strategic location: By connecting the productive Utica and Marcellus shale fields in Appalachia to the Transcontinental pipeline, a massive backbone conduit that links New Jersey to the Rio Grande Valley, it will make it easier for cheap natural gas to reach the population centers — and export terminals — of the Eastern Seaboard and Gulf Coast. That will, in turn, spur a modest increase in natural-gas drilling, which could increase American emissions by roughly 6 to 16 million metric tons a year, according to an estimate from The Washington Post.

The Inflation Reduction Act, by comparison, will eliminate roughly 660 million tons a year by 2030. So preserving the IRA is worth the carbon cost of this pipeline — but it would be better, of course, not to have to make such a choice at all.