The open-source project Cloud Carbon Footprint estimated the carbon footprint of storing 1TB in the Cloud. In their methodology they explain that they use the following numbers:
HDD average capacity in 2020 = 10 Terabytes per disk
Average wattage per disk for 2020 = 6.5 Watts per disk
Watts per Terabyte = Watts per disk / Terabytes per disk: 6.5 W / 10 TB = ...