BERLIN -- Researchers calculate that the electricity required for the virtual currency bitcoin generates as much carbon dioxide as a city like Las Vegas.

The Technical University of Munich said Thursday that researcher Christian Stoll and colleagues first calculated the power consumption of the entire bitcoin network. They then combined the results with the carbon emissions from electricity production in the countries where the computers were located, concluding that bitcoin's carbon footprint in late 2018 was 22-22.9 megatons of CO2 per year.

Stoll, who also works at the Massachusetts Institute of Technology, said the findings should prompt policymakers to consider regulating bitcoin so it uses mainly low-carbon, renewable energy.

Alex de Vries, a bitcoin expert who wasn't involved in the study, said the figures were plausible and probably on the conservative side.