Until 2025 anything dirty - tax is 3% for import
2028 tax is 6%
2030 - 12% etc...
Also rollout new target for next Phases. To get rid of coal first, Gas after, ICE cars, inefficient heating, metal production...
You can make it more complex to include coal in formula etc. So if energy production contains 15% of coal then tax this economy. If that doesn't work in few years double the tax. Very simple and efficient.
it make sense to make it social, and invest this tax into low income homes upgrades for electricity(solar), heat production(geotermal).
That basically makes the Carbon/dirty production a luxury.