re: #4 Tsuga

Yes. You have to distinguish between costs of installing different kinds of new power plants (one set of cost comparisons) versus the cost of actually closing and cleaning up old plants plus building new, cleaner ones (a different set of numbers).

Subsidies can easily solve this fiscal problem. The kind of politician who would oppose this approach would most likely also oppose a carbon tax. The subsidy approach would streamline the change compared to the carbon tax. And it’s more likely to happen because, let’s face it, the US government would rather subsidize businesses than tax them anyway.