That would only be fair if you required coal plants to pay for all the lives shortened or affected by its pollution. And that would be many orders of magnitude

That would only be fair if you required coal plants to pay for all the lives shortened or affected by its pollution. And that would be many orders of magnitude higher than the insurance that you are proposing. And no, CO2 taxes aren't the same (air pollution and global warming are separate things), and even then they are absolutely tiny.