He say it takes 2.55 GW now and "potentially 7.67 gigawatts in the future" because "Economic models tell us that Bitcoin's electricity consumption will gravitate toward the latter number"
I'm not sure what 'economic model' makes him able to predict that mining will triple from where it is now.
This would also imply 6.7 Billion dollars per year just to buy the btc that the miners generate and around 6 million mining rigs running at 1300W.
I think the economic model here is that until there is no marginal increase in profitability from increasing mining capacity, miners will continue to increase their capacity.
On May 15, 2017, global hashrate was 3.6 TH/s. Six months later, on November 15, 2017, global hashrate was 10.3 TH/s (source: blockchain.info). On May 14, 2018, another six months later, global hashrate was 30.1 TH/s, an increase of just under 3x in each 6-month interval. While past performance cannot definitively determine future performance, itβs a pretty strong trend.
I'm not sure what 'economic model' makes him able to predict that mining will triple from where it is now.
This would also imply 6.7 Billion dollars per year just to buy the btc that the miners generate and around 6 million mining rigs running at 1300W.