Carbon cost of High Performance Computing

ARCHER pulls 1.2 MW [1] to run it’s 4920[1] compute nodes (each of which is 24 cores). That’s just under 250 W power per node: 6 kWhr of energy in 24 hrs. A 24-hour single-node job consumes 8.6 ‘kAU’ in the internal compute units used for accounting.

So that’s roughly 0.7 kWhr / kAU, or 700 kWhr / MAU.

The UK electricity grid carbon intensity is roughly 400 g / kWhr averaged over the year: making 280 kg CO2 per MAU of Archer calculation.

A relatively small research project doing hybrid calculations can easily consume 10s of MAU: generating a lot of atmospheric carbon dioxide!

By comparison, an economy return flight from London to Boston (for Fall MRS) generates 800 kg of CO2[2].

So flying London to Boston and back for Fall MRS, adds as much carbon to the atmosphere as 3 MAU of calculations on Archer.

Interestingly, if you were to own a 24-node server in your lab continuously running calculations, this equals roughly 8.6 (kAU) * 365 = 3.1 MAU for the whole year.

My take home message was to be less concerned about the travel to conferences to present my energy-materials science, and more careful with spending HPC time wisely!

[1] [2]

Jarvist Moore Frost
Electronic structure theory