Some say, "There is so much more we can do to conserve energy". Of course there is, but there are financial and physical limits. You can add insulation to your house of even paint your roof white. You can't live in a thermos bottle. So there is a point were adding more insulation is not cost effective. Painting the roof white is fine, but you have to clean the roof to keep it white.
Is there a conspiracy by big oil and Detroit to keep 100 MPG cars off the road? No, there are real technological, financial and utility limits. You can build something close, but is not very useful. A one seater car with hard rubber tires and no get up and go limits consumer demand. The Chevy
A surprisingly large number of the public are second hand buyers. That is not just people buying cars it is also municipalities waiting for proven technology. There is no magic wand that anyone can wave to change things. You have to work with what you got.
As prices for energy grow, the options to save energy increase because they become more affordable. Take the car example, with gas at $1.50 a gallon it would be foolish to invest so much to save so little. With gas at $5.00 a gallon that new hybrid starts to look more attractive. The Chevy Volt would still be on the road with lots of buddies had gas prices stayed high. It is not that bright to artificially inflate gas prices just so you can see more Volts than Volkswagen. Trust me, poverty sucks.
Estimating future energy prices is needed to determine the value of energy options. Now, energy security issues adds to the criterion and potential global warming is in the mix. That all combines to make more energy options viable. Financially, bang for the buck is still a major issue with either your or the peoples money.
Security wise, the Department of Defense will lead the way on transportation fuels. That limits fuels to NATO compatible blends. There is some use of waste heat that can be included in manufacture of alternate energy types of these fuels.
The big uses for waste heat are in industry. The concrete industry can use power plant exhaust heat. Not for the full process, but to preheat materials prior to final processing. They use waste heat now, it will just mean that it worth the money to use more. Lumber kilns can use waste heat even ice making companies can use waste heat.
In the US, some where around 60% of the energy used by power plants is wasted. At the time they were built, technology and finances greatly limited efficiency. In today's world that can be reduced to 50% and with a little extra need even 40%. That will decrease energy use by 20% with only one catch. That improved efficiency will not be just electrical output. It requires joint government/business partnerships to explore waste heat recovery options.