The market price of Bitcoin and other cryptocurrencies is plummeting, having dropped by 10 per cent just today, and 50 per cent over the past month. The bubble that reached maximum expansion a year ago is gradually deflating.
The good news is that a lower Bitcoin price makes the energy-wasting process of Bitcoin mining unprofitable for many, so lots of miners are turning off their servers. Most estimates of the marginal cost of mining are around $4500 per coin, but the market price has just fallen to $3500.
That situation won’t last long. Every couple of weeks (more precisely, every 2016 blocks) Bitcoin adjusts the difficulty of the pointless algorithm used to mine coins, so as to ensure a steady flow of around one every 10 minutes. As mining effort has declined, the difficulty is reduced, which means less electricity wasted per Bitcoin.
The rapidity with which Bitcoin prices are falling give some hope that the entire disastrous episode will soon be over. If the current rate of decline (50 per cent per month) is maintained, Bitcoins will be worth less than dollar coins in a year’s time, and their impact on electricity demand will be negligible. That’s equivalent to taking a small country like New Zealand off-grid.
In this context, it doesn’t matter whether Bitcoin miners are using renewable energy or coal. The opportunity cost of the electricity they use is the coal-fired electricity that would otherwise be displaced by renewables.
fn1. As shown here, mining difficulty leveled out in September and started declining in November. Since electricity consumption depends on both mining difficulty and the speed of the machines being used, which is increasing over time, the energy wasted on Bitcoin probably started declining modestly as soon as mining difficulty leveled out.