US’ best source of carbon-free energy is efficiency . Not just the US of course. The laws of physics are the same all over the planet.
The McKinsey report  [pdf] arrived at [its] figures by performing a fairly simple economic analysis: what measures, if rolled out on a large scale starting in the near future, would have a positive return on investment by 2020. Those are fairly conservative conditions, since many efficiency projects require a substantial up-front investment that’s only paid back gradually; time horizons longer than a decade aren’t uncommon when it comes to payback. Nevertheless, the numbers were staggering. $520 billion worth of investments would produce a total of $1.2 trillion in savings by 2020. Presumably, the numbers would look even better later into the century.
At 2020, we’d be avoiding using that 9.1 quadrillion BTUs. That would be enough to knock 23 percent off the expected demand, dropping it below the current national usage. It’s worth pointing out that there’s a bit of a multiplier effect of efficiency efforts, as well—by not producing the energy in the first place, all the losses that occur during generation and transport never come into play. The net result would be over a gigaton of greenhouse gas emissions avoided as well.
As far as the National Academies is concerned, the McKinsey report might just as well have been a chapter in its own publication . “The deployment of existing energy-efficiency technologies,” it has concluded, “is the nearest-term and lowest-cost option for moderating our nation’s demand for energy, especially over the next decade.” [emphasis added]
So could we now get with the program and stop chasing more pollution with less power? Crap like “clean coal” and nukes. And, environmentally less appalling but socially more so: food-sourced biofuels. Here’s yet one more repeat of what’s wrong with them.
“Clean” coal  produces all the same destruction and pollution — and energy costs! — during mining as dirty coal. And another not-so-minor data point: the industrial-scale process to do it has not been invented yet  (pdf, eg p. 31).
Nuclear energy : Produces pollution, environmental destruction, and uses energy during mining. Uranium is a finite resource. A finite resource. It will . . . wait for it . . . run out. (Am I frustrated that some people don’t get this yet? Yes, I’m frustrated.) It will run out in about a century if used to produce most of our energy. It takes time to build plants. One plant would have to be built every six weeks, starting yesterday, going on until the uranium runs out, to produce most of our energy. Nuclear energy creates radioactive waste. We have no viable method of dealing with current waste, forget the amount of waste that would be generated by a bigger nuclear program. Decommissioning costs are huge and underfunded. Companies are mothballing old plants to delay the day of reckoning  when people are presented with the price tag. All that money spent on nuclear energy to get a fraction of the power needed cannot be spent on real solutions.
Biofuel  produced from corn and other food sources: Destruction of habitat to grow monocultures of energy crops (a problem with any biofuel not generated from waste). Increased food prices in a world where around one billion people are living on around one dollar a day. That leads to even worse mass starvation than we already have. That leads to even more mass migration, social dislocation, riots, and wars. Just in case I’m not being clear, this is Not Good.
Now that we have yet more studies all saying the same thing, how about we all get on the same page and DO THE OBVIOUS!
energy, efficiency, NAS, McKinsey