Old coal plant is now mining bitcoin for a utility company

Old coal plant is now mining bitcoin for a utility company

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Bitcoin’s massive power consumption is cryptocurrency’s dirty secret. To mine bitcoin, computers across the globe chew through enough electricity to power a medium-size country, somewhere on the order of the Netherlands or Poland depending on the estimate.

In fact, electricity has become such a significant factor that one private equity firm owns a power plant to mine bitcoin. The company, Greenidge Generation, said at one point that it could mine one bitcoin for less than $3,000. Even today—at $40,000 per bitcoin, some 30 percent off its peak—the potential for profit is real.

Which is why an investor-owned utility has dropped a containerized data center outside a coal-fired power plant 10 miles north of St. Louis. Ameren, the utility, was struggling to keep the 1,099 MW power plant running profitably when wholesale electricity prices dropped. But it wasn’t well suited to running only when demand was high, so-called peaker duty. Instead, it’s experimenting with running it full-time and using the excess electricity to mine bitcoin.

Can’t cope with the load

Ameren executives reportedly blame wind and solar power for the load variability that taxes the 55-year-old power plant. The utility claims that mining bitcoin could reduce its carbon footprint by allowing it to run its plants more consistently rather than ramping them up and down, which they say can increase emissions.

“We have pretty dramatic changes in load minute by minute, second by second at times,” Warren Wood, the utility’s vice president of regulatory and legislative affairs, told E&E News. But when it’s running full time, they only have to take power away from the mining operations. Wood said it takes about 20 seconds to divert power back to the grid.

Compared with gas peakers, which typically need at least five minutes to ramp up to full capacity, that’s pretty quick. But it’s also incredibly slow when compared with grid-scale batteries, which can respond within milliseconds.

Across the entire grid, cryptocurrency mining operations could “add a lot of value, particularly how fast they can move up and down, Joshua Rhodes, a research associate at the University of Texas at Austin, told E&E News. “It can have a positive emissions impact if it’s run the right way,” he said. “It can also increase emissions if it’s not.”

“Slippery slope”

Ameren attempted to get rate-payers to foot a portion of the bill for its experiment, but Missouri’s consumer advocate pushed back. “If Ameren Missouri wants to enter into speculative commodities, like virtual currencies, then it should do so as a non-regulated service where ratepayers are unexposed to the economics of them,” Geoff Marke, chief economist for the Missouri Office of the Public Counsel, wrote in a filing. “This endeavor is beyond the scope of intended electric utility regulation, and, if allowed, creates a slippery slope where ratepayers could be asked to put up capital for virtually anything.”

The utility says that if its bitcoin experiment pans out, it could attach similar containerized data centers to wind and solar farms to soak up excess electricity profitably in times of high supply or low demand. The coal-fired power plant that’s being used in the experiment is scheduled to be shut down in 2028.

Ameren says that so far it’s pleased with the project, which has mined 20 coins and mints a new one at a rate of one every 15 days or so. Whether the math continues to work depends largely on the cost of running the plant and the price of bitcoin, which is highly volatile. Based on today’s prices, the company has made about $800,000 since it switched on the miners in April.