"Renewable resources could produce 25 percent of the electricity and motor vehicle fuels used in the United States by 2025 at little or no additional cost if fossil fuel prices remain high enough and the cost of producing renewable energy continues falling in accord with historical trends, according to a RAND Corporation study ..." (Note: pdf version of full report is free under this link.) 'Significant reductions in carbon dioxide emissions from fossil fuel combustion (15 percent of projected U.S. emissions) can be achieved. In addition, an estimated 2.5 million barrels of oil consumption would be displaced, according to the study'. What makes the Rand study especially noteworthy is that the authors went through numerous scenarios in their modeling. Now what we need is the converse benchmark, projecting what kind of cumulative US energy conservation levels can be achieved with an all out effort by both public and private sectors, with renewables set at the prospective 25% level. With both studies done, the tricky part would come when setting policy for the confluence of conservation programs and renewable energy growth. For example, should a conservation focused program be blind on the extent to which it seeks to conserve fossil vs renewable energy? Some might argue that conservation programs should primarily target situations where non-climate forcing environmental burdens, like mercury emissions from coal, are significant public health threat. If that were the policy tact, places like the Pacific Northwest and Buffalo New York, where renewable hydropower, instead of coal, is a dominant source of electricity, would deserve lower levels of Federal energy conservation support. Conversely, Texas, which is already choking on coal-fired electricity, and just can't seem to get enough of it, would warrant a higher level of energy conservation support. Not saying this would be the "right" choice. Just pointing out the tricky value judgements that must be made once both renewable and conservation benchmark projections are done.