How about forms of energy that already are consumables? Consider batteries, for example–ideally they’ll eventually be replaced by something smarter and more renewable, but in the meantime there are a LOT of applications for batteries. Rechargeable batteries exist–why don’t more consumers use them? Is there a way to make long-lasting/rechargeable batteries as attractive as a cheap pack of Duracell AA’s?
Another thought: focusing on a specific energy use, like energy in the home. (Something I learned recently: despite all the fuss about SUVs, buildings, overall, use up waaaay more energy than cars, overall; a big improvement in building energy-use efficiency would conserve millions of tons of fossil fuels.)