As soon as you add that requirement to coal power plants, they become immediately uneconomic to build or operate. They are already borderline due to the fall in cost of renewables.
With a meagre Carbon Tax of $15/tonne, coal costs double in the US.
There's nothing that can be done to fix coal power apart from just shutting it all down.
Isn't that the whole appeal of our economic system? To root out these inefficiencies?
If it is not economically feasible to run a coal plant if they do not externalize the pollution cost, how is that my problem? And if the demand justifies it, the cost for coal-generated electricity will go up.
It's a matter of priorities and resource allocation.
Why do we allow coal operators to enrich themselves at the cost of everyone else?
The negative externalities are too many degrees of separation and to many years away from any immediately obvious perception of harm.
"Officer, these men are stealing my lawn, a few blades of grass a day as they walk by!" This doesn't engender a threat response until there's visible damage, and even then the solution is likely to involve signs and warnings, since the responsibility for total damage is so widely distributed. We need a fence around the climate lawn, and we can't leave the gate open for some people and not others, if you catch my drift.
We're beginning to see global acknowledgment of the problems and gradual progress towards reducing emissions. Once technology can accurately measure the cost of the negative externalities, they can be priced in. If the cost is on an exponential trend, where each ton of co2 is now seen to cost the operator an additional .0000001 cents, but 100 years later might cost millions, with regards to preventable damage, markets currently are accurately pricing in the costs. They're just not equipped to assess global climate and long term planning as relevant. That has to come from legislating sane and scientific and fair rules.
There's nothing inherently wrong with burning coal if there's a globally recognized system of accountability. Since there's not likely to ever be such a hegemony, you get what we have now - slow, frustratingly bureaucratic incremental progress, and therefore the need for mitigation as well as sustainable energy tech.
The EU has much higher pricing of CO2 (currently at 60 eur / tonne [0]) and yet Germany was using more coal power than expected, forced by the fact that there was a scarcity of wind. [1]
Of course, that caused the prices of electricity for households to jump up. [2]
Carbon Tracker calculates that the majority of coal plants in Europe are already cost negative.[1] They live off uncompetitive tariffs and subsidies. Germany's reverse auction for coal plants over the last year ended up accepting a lot of very low bids, as coal owners were desperate to get out from under stranded assets. Even they were widely criticized as over-priced given the state of the industry.
If you're considering whether coal plants would exist at all, you need to compare to the price of things like batteries. (Unless we make a ton of nuclear.)
It would be great to do sane carbon policy, but politics is the limiting factor at the moment. Carbon capture is one of the few universally popular solutions.
With a meagre Carbon Tax of $15/tonne, coal costs double in the US.
There's nothing that can be done to fix coal power apart from just shutting it all down.