As part of my Master and PhD theses I have used a lot of computer time on supercomputers in Jülich, Stuttgart, Bologna and the cluster in Bonn. I want to estimate the magnitude of CO₂ that this has released.
It is a bit hard to say how many core hours I have used exactly as I have already used data that existed already. Let's take like 5 Mh to pick a number. Then on JUWELS with the dual Intel Xeon Platinum 8168 with 48 cores that is around 100 kh. Each of the CPUs has a TDP of 205 W. Then there is network, file system, backup. Perhaps 750 W per node? And then there is cooling, which roughly takes the same on top, so 1.5 kW per node. That makes 150 MWh of electricity used. In Germany it seems that we would have to take 0.4 kg/kWh of CO₂. This would then give a little over 60 t of CO₂.
This in itself lacks a comparison scale. Assuming a usage of 6 l/100 km of Diesel fuel, one gets an emission of 0.3 t CO₂ per 1000 km driven, or 0.3 kg/km. This make the equivalent of 200,000 km car driving. Assuming like 15,000 km/yr that would be a little over four years of car driving.
Personally I use around 1500 kWh of electricity at home. In this way I have consumed a lifetime of household electricity as part of my thesis.
Perhaps the best comparison is to the average German who apparently emits around 10 t/yr. Then I have emitted another six years worth of emissions, I basically have lived at three times the average footprint. Guess I will have to cycle a lot to compensate that.