Money is redeemable for anything, from anyone. En un viejo país ineficiente, algo así como España entre dos guerras civiles, poseer una casa y poca hacienda y memoria ninguna. -- Gil de Biedma
I would propose as a starting point membership by energy users and consumers alike of an International Energy Trade Association (defined by use of a transaction registry) and then to build an Energy Pool, Guarantee Society upon that foundation, and apply unitisation within the resulting framework.
I think that you would be hard pressed to find people not prepared to accept a Unit redeemable in energy if such a framework of trust existed.
Note that I see Units redeemable in energy as a global reserve currency. Units redeemable in land rental value would probably comprise most of the value circulating locally. "Any economic unit can emit money. The serious problem is to get it accepted" Hyman Minsky
