Unlike the dollar or the pound, these virtual "coins" aren't tied to a central bank. Instead, bitcoins are "mined" by computers in vast data centers that guzzle huge amounts of energy.
Bitcoin uses about 32 terawatts of energy every year, enough to power about three million U.S. households, according to the Bitcoin Energy Consumption Index published by Digiconomist, a website focused on digital currencies.
By comparison, processing the billions of Visa transactions that take place each year consumes the same amount of power as just 50,000 American homes, according to Digiconomist.
The country's hinterlands have proved attractive for the data centers that bitcoin mining requires because "electricity and land are very cheap," researchers at the University of Cambridge wrote in a recent study.
A lot of the energy in provincial China comes from inefficient, coal-fired power plants that were built in anticipation of big construction projects that never happened, according to the researchers.
Big bitcoin miners have defended their operations, telling the Cambridge researchers that they believe their environmental impact pales in comparison with that of extracting natural resources such as oil.
And more eco-friendly power sources are being adopted. Vienna-based HydroMiner, for example, uses renewable hydroelectric power for its bitcoin operations
But some experts are very pessimistic about the future.
The Chicago Board of Options and Chicago Mercantile Exchange will allow investors to start betting on the future price of bitcoin later this month.
That is expected to prompt a flurry of interest from the big, professional money managers who have so far stayed on the sidelines of the bitcoin party. More demand for the digital currency is likely to push energy use even higher.
"The CME futures may institutionalize bitcoin, which would be disastrous [for the environment]," said John Quiggin, an economics professor at the University of Queensland.
Quiggin believes policymakers won't be able to ignore the fallout for much longer.