That's at 19 megawatts burning natural gas. So that means they spend about 140MWh of energy for one BTC. I calculate that comes to around $20/MWh, which seems

That's at 19 megawatts burning natural gas. So that means they spend about 140MWh of energy for one BTC. I calculate that comes to around $20/MWh, which seems to be on the low side of energy production. Coal is $40 to $143 per MWh. Edited to add: That's roughly 60 tons of CO2 emissions per BTC mined. https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 The other aspect here is let's say you're a speculator and you think the price of BTC can go up another 50x or roughly $1M/BTC. Then even spending any amount less than the BTC spot price now is a bargain.