Energy consumption is by far the low hanging fruit on the sustainability tree. Since, according to Energy Information Administration, a whopping 65% of the energy produced by mostly non-renewable sources is lost in conversion processes, it stands to reason to look closer at these conversions and develop more efficient technologies to get what we need.
Seen from this perspective a lot of the current market trends head in that direction. The transition of incandescent lighting to the substantively more efficient CFLs is a good example. No sooner the industry “switched” there another, even more efficient technology showed up: LEDs.
We’ll see this in cars quite soon. The electrical motor is way more efficient than the combustion engine. Once the battery issues are mastered (by the way, another energy conversion issue) there would be no stopping it.
Examples in the component area abound: appliances especially water heaters, washers and refrigerators, AC units, motors, transformers, etc.
But systems are in my view the areas with the fastest payoff. You’ll find them in the commercial buildings. You start applying modern daylight harvesting, combine it with advanced heating/AC systems and efficient building materials and architectural concepts, back all this up with some local energy storage all conversant with the smart grid and you could stop dreaming about a net zero-energy building and actually start build it! Now!