By far, the most frequently cited estimate in news media is the Bitcoin Energy Consumption Index (BECI), which uses a top-down approach that assumes miners spend (on average) 60% of their revenues on electricity at a rate of 0.05 USD/kWh. These key assumptions have been criticised to overestimate electricity consumption; indeed, BECI estimates represent the high range of published estimates to date.

Bendiksen, Gibbons (2018; 2019) & Lim (2018) also use a top-down approach, but undertake significant data collection efforts on existing mining hardware and mining locations to inform their assumptions and analysis. They also conduct sensitivity analyses around key uncertainties, including electricity costs and capital depreciation schedules. Under their central assumptions, they estimate that the bitcoin network consumes between 35 TWh (May 2018) and 41 TWh (November 2018; June 2019) per year.

Other researchers have calculated lower-bound estimates using a bottom-up approach (e.g. Deetman, 2016; Morgan Stanley, 2018; Valfells & Egilsson, 2016). This approach assumes that all miners are using the most efficient mining hardware to achieve the network’s hashrates (TH/s). The Bitmain Antminer S9 series (0.1 J/GH), used by two-thirds of miners worldwide, is typically used as a benchmark.

Using this approach, we can estimate that thebitcoin network (excluding cooling) consumed 31 TWh in 2018. Based on data collected from mining facilities in China, cooling and other ancillary demands accounts for 30% of electricity use overall, thereby adding another 42% to the lower-bound estimate. Therefore, we estimate that bitcoin mining consumed around 45 TWh in 2018, which aligns well with the latest peer-reviewed estimate of 45.8 TWh as of November 2018 (Stoll et al., 2019).

With the recent run up in price and hashrate, energy consumption is expected to be much higher in 2019. Through the first six months of 2019, bitcoin mining has already consumed an estimated 29 TWh.

While these early estimates provide a rough indication of bitcoin energy use today, it is clear that researchers need more data, in particular from mining facilities, to develop more rigorous methodologies and accurate estimates.