4DS - Anything but Charting, page-30084

Airliners' largest operational expense is their fuel cost.

They spend a significant amount of effort working out ways to save fuel, by using lighter materials, eliminating dead weight on their planes. An innovation that saved 2% (which would be a lot) of their fuel bill translates into a significant dollar saving.

Same for data centres - electricity is the largest operational expense - if you could save 2% of the electricity bill that has a significant dollar saving. That's notwithstanding, a lot of the energy consumption in a datacentre ends up as heat, which has to be handled. If you're generating 2% less heat, that's smaller chillers, smaller grid interconnects or 2% more equipment you can jam into your building.