Around 80% of Firefox users are on Windows, per https://data.firefox.com/dashboard/hardware

That same site also suggests that Firefox has around 200e6 monthly active users, the average user uses Firefox 3.5 days a week, and for 5.5 hours per day.

My math could be wrong, but taking the above into account, and arnaudsm's 5 W estimate, I come up with an upper bound of around 80 MW. Discount that further by whatever proportion of Windows users you assume were actually affected. Not a whole coal power planet, but nothing to sneeze at.

Wow, that's fascinating. It really speaks to the utter dominance of Windows over Linux more than anything else. Like even among Firefox users, as of last year, there were an order-of-magnitude more Windows 7 and 8 users than Linux 5.x users.

Don't have any data to back this up, but I would think that the average linux user will instantly turn off firefox telemetry and won't show up on these graphs. It's one of the first things when I install firefox, disable ff telemetry, set privacy mode to strict and then install uBlock. Nevertheless Windows has a huge market share, even if no one turned off data collection, and the year of linux on desktop didn't happen.

Similar numbers can be seen with Steam demographics: Linux is nothing compared to Windows 7, to this day.

Windows 7 - 1.6%

Other - 4.09%

https://www.statista.com/statistics/265033/proportion-of-ope...