I think that the liquid fuel powered Internal Combustion engine, that can be adapted to run on many fuels (gas, diesel, alcohol blends, biodiesel, etc.) at a high efficiency is an important step.

Any product is going to cost more energy to make than you get out of it. It's called the three laws of thermodynamics.

The good thing is that people are starting to think holistically about the total carbon footprint of a product or process, at the grass-roots level. There are loads of small things that are starting to be done that add up.