This post depicts the scenario if the energy pessimists are correct.
The moderate among the energy pessimists do not think that the world will run out of energy. They are very much aware that the sun beats down more energy in a week than civilization uses in a year or something. However, society with its present design and structure cannot capture that. Most of our present energy needs are being obtained from concentrated sources like coal, not from diffused sources like solar and wind.
If the energy pessimists are even slightly correct, then the available excess energy flow is on a slow decline. Energy is a must have. As for energy flow, generally, the more the better for industrial civilizations, but paraphrasing the architect in the matrix said, "There are levels of survival we have to be prepared to accept". This means an energy based currency may appear, by default, if not by design.
In an era where the general consensus has shifted that energy flow is declining and will continue to do so for a while, for governments who are not already rich in precious metals, an electricity based currency could be quite attractive to signal currency strength.
In the long run, bitcoin is dominated by energy costs. But bitcoin's distribution is to make it attractive for early adopters. Governments who have taxation powers are not in need of such a distribution scheme.
The best way to go about an energy based currency is to set a value for kwh wrt M1 and then set a target time for present banks to become zero maturity transforming institutions (100% reserve banking). Then allow any powerplant or a power grid operator near any sufficiently large city to print money once in a quarter based on the power that it sold to the city in the last quarter. As more money gets printed by the power plants and the grid, the reserve ratio in the banks is increased until the banks move towards zero maturity transformation (all long term loans backed by long term deposits). Once 100% is reached, the central bank can shut shop.
The advantage of the electricity backing over commodity backing is that it is extremely difficult to substitute electricity in common usage today. Regular quarterly payment of the electricity bills keeps the whole thing real. Imagine if the gold standard were constantly being audited by actual redemptions every quarter.
If the energy pessimists are correct, this will not lead to hyperinflation since it will not be possible to create power plants very easily because the easy sources of creating power are more or less all over. Intense energy research would happen since no one would actually give away a chance to print money. The currency would freely float with respect to other currencies and commodities, but it would be "redeemable " only in the mother country.