Let the economics engender the savings. Efficiency is a two-edged sword. If somebody invented a light-emitting diode, you'd get this bright light and almost no energy. What are we using here? It didn't displace very many lights, but every billboard in the airport is a sheet of these things, which uses a lot of energy because there are a lot of LEDs. Why are there a lot of them? They are so cheap, and each one uses so little.
The way you make automobile engines more efficient is you make them bigger and run them faster. That's how you can make them more efficient. That's what you do. Look at the size of engines in vehicles today. You look at the efficiency of just the vehicle system and you're maybe around 20%, but now you want to move a single body that weighs 150 pounds, and that's only one-thirtieth of the mass of the total vehicle, so now you're down to an overall efficiency of three-quarters of a percent. The efficiency is how much energy it takes to move me from where I am to where I want to go. If the vehicle weighs one-half, you've doubled the efficiency of the actual system.
Anyway, those are just two examples. Efficiency is a two-edged sword.