I don't really want to ridicule Kevin Drum here for thinking out loud. I really hate partisan Conservative and Liberal team-politics blogs, but I read a few to stay out of the echo chamber, and Drum is smarter and incrementally more objective (a relative thing) than most.
These two things together reminded me about an energy factoid that's always struck me as slightly odd: virtually every form of energy seems to be almost as efficient as burning oil, but not quite.
For example, on either a power/weight basis or a cost basis, batteries are maybe 2x or 3x bigger and less efficient than an internal combustion engine. Not 50x or 100x. Just barely less efficient. And you see the same thing in electricity generation. Depending on how you do the accounting, nuclear power is maybe about as efficient as an oil-fired plant, or maybe 2x or 3x less efficient. Ditto for solar. And for wind. And geothermal. And tidal power.
I'm just noodling vaguely here. Maybe there's an obvious thermodynamic explanation that I'm missing. It's just that I wouldn't be surprised if there were lots of ways of generating energy that were all over the map efficiency-wise. But why are there lots of ways of generating energy that are all surprisingly similar efficiency-wise? In the great scheme of things, a difference of 2x or 3x is practically invisible.
First, we have to translate a bit. He mentions power to weight ratios for batteries in the second paragraph. In fact, batteries have terrible power (actually energy storage) to weight ratios vs. fossil fuels, much worse than 2-3x for energy storage per unit of weight or volume. That is why gasoline is still the transportation energy source of choice, because very few things short of plutonium have so much potential energy locked up in so little volume. But I will assume he is comparing an entire electric drive system compared to a gasoline drive system (including not just energy storage but the drive itself) and in this case the power to weight ratios are indeed closer.
But here is the problem: in engineering, a 2-3x difference in most anything -- strength, energy efficiency, whatever -- is a really big deal. It's the difference between 15 and 45 MPG. Perhaps this is Moore's Law corrupting our intuition. We see electronic equipment becoming twice as powerful every 18 months, and we start to assume that 2x is not that much of a difference.
But this is why Moore's Law is so much discussed, because of its very uniqueness. In most fields, engineers tinker for decades for incremental improvements, sometimes in the single digit percentages.
The fact that alternative energy supporters feel like their preferred technologies are just so close, meaning they are only 2x-3x less efficient than current technologies, explains a lot about why we skeptics of these technologies have a hard time getting through to them.