I don't understand where these power and cooling mantras came from, but large-scale cloud providers have very low PUE (Google publishes historical data at https://www.google.com/about/datacenters/efficiency/). That means you can take the basic power from a thread, add some for memory, and multiply by just a bit to get Watts. Take that and plug in your favorite $/kWh guess and get a price.
Ignoring Graviton, which doesn't have published power data to my knowledge, you can look up the TDP for a bunch of chips and see that it's a a few Watts per thread [1]. Similar calculations can be done for RAM. You end up at 5ish Watts per thread with some RAM attached. Let's call it 10 all in with cooling or other stuff. Since 10W is 1% of a kW, we end up with .01 kWh per hour. The top hit for "us power commercial rates" [2] says that we should assume 7c per kWh or so. That means our instance with cooling and overheads, needs to include .01 x .07 => $.0007/hr of power and cooling costs.
A single core w/ 4 GiB of memory on GCP at 3yr commitment rates (so we're focused on the long-term depreciation price) is .009815 + 4x.001316 => $.015/hr or about 20x as much as the power.
tl;dr: Power costs add up, but they are not even close to dominating the costs of cloud pricing.
[1] https://wccftech.com/amd-epyc-7h12-cpu-64-core-zen-2-280w-td...
[2] https://www.statista.com/statistics/190680/us-industrial-con...