Meanwhile in Germany:
Fossil fuels means it’s something we are digging up and have a limited amount of, as opposed to renewable energy. It doesn’t mean it’s necessarily fossilized lifeforms. Uranium and other radioactive metals are exactly like that, something we dig up and can run out of.
And even then, although there’s a finite amount of Uranium on Earth, the amount there is could last us thousands of years. Enough for us to get a replacement, like fusion, working.