We will always need coal.
Coal is REQUIRED to smelt steel. There's no other way to MAKE steel. The carbon in coal, and the slow hot burn, is REQUIRED.
Oh, we'll use free energy for heating our houses and our hovercars. But as long as we need steel, we'll need coal.
We are the Greek chorus of frogs from Aristophanes' 'The Frogs'
The choral interlude (parodos) [note=parody], sung by the eponymous chorus of frogs. Their croaking refrain – Brekekekèx-koàx-koáx – greatly annoys Dionysus, who engages in a mocking debate with the frogs.
You probably should have stopped lurking long ago