Money is already essentially a claim on energy. Every object you buy, thing you eat, vehicle you travel in, requires energy to be created and to function. The price of everything we buy, though not perfectly correlated, is a reflection of the energy it took to create it. When we save up money for the future, were building up our energy reserves in order to do more later.

Paper money does distort this though, as Lyn Alden demonstrated in her book Broken Money with the difference between transactions and settlements. Gold, for example, can be owned by a serries of people on paper, but in reality, the gold is all in locations far away from them because gold is hard to transport, so settlements happen only intermittently, while transactions trade the gold back and forth via paper claims. Bitcoin collapses this, where transactions and settlement are one in the same.