Chemically gasoline is Octane, C8H18, which is, as you can see, a fairly simple hydrocarbon. "Dung" implies all organic waste, not only what cows produce.Huseng wrote: You're dreaming if you think you can maintain let alone grow industrial civilization with cow dung.
Crude oil found in earth is also a biological waste product, it is not something radically different from dung. This means that we can make from "dung" chemical products very similar to the hydrocarbon octane. Their energy density will be on the same level with Octane.
Energy in the form of electricity is same amount of energy as energy produced from oil products. It is capable of doing exactly same work. This is basic physics.
If you insist, it is possible to transform electricity into a liquid or a gas, that contains energy.