It all matters on what nation you're in and where in that nation. A quick google showed this for the US : In the U.S., hydropower is produced for an average of 0.85 cents per kilowatt-hour
I am in the US..... $.85 is way too high for any sort of power. I think you might have your decimal in the wrong place.
I have seen $.03 - $.06 for a range. What I was hoping to get is what miners are really paying.
He may well have it right at .85
CENTS per KWh. It wouldn't surprise me if that is close to the marginal cost of a Hydro plant Kwh. That of course isn't what a customer pays to have it delivered to their house, with some money being put away when it's time to actually do a major overhaul at the plant.
I expect some research on Washington State will get when you are looking for.