If Bitcoins are backed by energy who is the issuer of the coins and in what form will they deliver the energy and how much energy will the issuer deliver for each coin?

Gold is not "backed by energy" nor is gold "stored energy" or anything like that. Rather, the energy required to find, extract & refine gold is a limitation on supply. There is zero energy *demand* for gold. Nobody buys gold so they can go to the issuer of gold (God himself, or at least a supernova) and redeem each tz of gold for a certain volume of oil or a certain number of kilowatt-hours of electricity.

But, when the dollar was backed by gold this is precisely what happened. A perfectly valid way to get gold was to first acquire US dollars and then proceed to the issuer of dollars and exchange them for gold, at a fixed exchange rate and for a predetermined form of gold.