Since bitcoin emerged from the internet’s muddy bottom into a global asset class, there have been many attempts to understand what this computation-based currency might mean for the world. No claim about bitcoin, or “the blockchain,” as the general category of technology is known, is too big for advocates (“the most disruptive tech in decades”) or detractors (the “biggest bubble in human history”).

But a profile of the town of East Wenatchee, Washington, by Paul Roberts in Politico Magazine is a must-read revelation about the physical reality of bitcoin mining. Whatever else bitcoin might be, it is—first and foremost—a way of converting electricity into money.

Bitcoin mining is what we call programming computers to do arbitrarily complicated calculations in a puzzle competition that gets harder as time goes on. The hardware and software necessary to do this are, more or less, commoditized. Mining has always been an aspirational name, but if we accept the metaphor, the miners are mining electricity.

So, to make money as a bitcoin miner, the only things that really matter are scale and access to cheap electricity. That’s sent bitcoin miners scurrying all over the Earth looking for low electricity prices. They tend to find it near big dams, which corral river water through massive turbines. In the right geographical circumstances, this can generate the cheapest power on earth. And East Wenatchee is one of these places, thanks to the Columbia River and the Rocky Mountains that lend the water its power.

Before cryptocurrency mining came to the region, locals enjoyed very low power prices because the local utility sold power at higher prices to other regions. “The region’s five huge hydroelectric dams, all owned by public utility districts, generate nearly six times as much power as the region’s residents and businesses can use,” Roberts writes. “Most of the surplus is exported, at high prices, to markets like Seattle or Los Angeles, which allows the utilities to sell power locally at well below its cost of production.”

This subsidized electricity is what the bitcoin miners seized on. This was an arbitrage that worked. “By the end of 2018, according to some estimates, miners here could account for anywhere from 15 to 30 percent of all bitcoin mining in the world,” Roberts writes, “and impressive shares of other cryptocurrencies, such as Ethereum and Litecoin.”

Five years ago, that might have generated a decent bump in electricity consumption, but remember, bitcoin mining is designed to use more resources as time goes on. To keep up, bitcoin miners have had to make tremendous leaps in scale. In 2012, a bitcoin mining outfit might have measured its consumption in the kilowatts.

Now, the sites are scaling up so fast that we’re talking about gigawatts, which are thousands of megawatts, which themselves are thousands of kilowatts.

“Over the past 12 months or so, the three public utilities reportedly have received applications and inquiries for future power contracts that, were they all to be approved, could approach 2,000 megawatts—enough to consume two-thirds of the basin’s power output,” writes Roberts.

One estimate of the bitcoin network’s total energy consumption, the Bitcoin Energy Consumption Index, is up to 55 terawatt hours. A terawatt-hour would be 1,000 gigawatt-hours. The orders of magnitude just keep piling up.

And that’s after taking into account the substantial energy-efficiency improvements that miners have made.

Back in East Wenatchee, new infrastructure will be required to keep feeding the mining rigs. And of course the costs for those substations and distribution lines will fall, partly, on the public utilities. It’s a remarkable hustle. And what if the industry implodes? Then, the locals will be left with an overbuilt (and therefore more costly) electrical infrastructure and a bunch of empty warehouses.

The point, too, is that the scaling-up process cannot stop. That’s how the system has been built. Even if bitcoin mining’s power needs, in the global energy picture, are still negligible. To realize the technology’s backers’ visions, the electrical consumption would have to keep growing at this breakneck pace. At a time when climate change requires that energy demand be bent downward, bitcoin miners sucking up city-size supplies of cheap and carbon-free hydroelectricity is a massive problem. And in China, where most mining is done with subsidized electricity produced in coal-fired power plants, it’s an even bigger problem.

This externality alone could wipe out a range of the benefits that bitcoin advocates imagine could result from the use of cryptocurrencies. Let’s stipulate that blockchains are useful and interesting. But will they be worth the energy it takes to do all that computation?

Bitcoin was incubated in libertarian circles, but it depends in part on government largesse. As in Washington, electricity production usually involves government subsidy of one kind or another. This makes sense: Access to electricity is one of the keys to economic development and pretty much any definition of a good life. But it also stands as one more reason that bitcoin ought to be regulated, just like the rest of the banking industry.