From Adam Ozimek, here are some very good points, which I had not previously pondered:
…what a carbon tax does is push the required cost threshold up. This would allow solar to become the more profitable source of energy in the US sooner and increase the speed of its dominance here.
However, a carbon tax would raise the threshold in the US relative to the threshold for developing countries. In other words, the race for solar companies in the U.S. becomes to be cheaper than dirty energy + a carbon tax, which is a higher threshold than being cheaper than dirty energy alone, which is the threshold in many developing countries.
It is easy to see how this could cause downward march in solar costs to slow, and as a result solar would reach the threshold for China, India, and other developing countries perhaps much much later.
If this is true, it would suggest that for clean energy to become globally dominant faster it’s better for the U.S. to just subsidize solar innovation and let the untaxed U.S. market price of dirty energy stand as a strong incentive for solar to drive costs lower.
To see this, consider a world where solar was already dominant in the U.S. with current technology and costs, perhaps via a total ban of dirty energy. The supply curve of the installed base of solar technology would be much more price inelastic than the supply curve of today’s installed base of dirty energy due to higher fixed costs and lower marginal costs. This means a steeper residual demand curve for marginal innovators that provides less market share rewards for marginal declines in price, and therefore lower rewards for marginal cost cutting.
In this way, a carbon tax could make global warming worse.
From Jerry Taylor at the new Niskanan Center, here is a paper on the conservative case for a carbon tax.