Funneling subsidies and tax breaks from fossil fuel to sustainable energy sources. In the Netherlands alone, the around 40 billion euros are spent by the government each year directly or indirectly subsidizing fossil fuel.

Kerosine airplane fuel is untaxed for example, while consumer car fuels carries a 20% (ish) tax.

Charging them for the negative externalities. Like coal kills way more people than nuclear but there’s no tax on coal plants for the harm caused.