I attended a lecture on tidal-power schemes, about four years ago. (Sea-floor open turbines using the normal currents, not water stored behind a tidal dam).
It seems this country is an international leader in R&D of that but of course, officially has a fetish for sun and wind only!
More to the point though, the speaker told us briefly of an estimate by BP, whom you would expect to be optimistic not pessimistic, of probable depletion of coal and oil reserves assuming extraction continues.
Its figures were based on present extraction rates and (obviously!) known tapped and awaiting deposits, but finding new ones is becoming harder and costlier:
– Oil: around the middle of this Century.
– Coal: around the end of the Century.
Errr…. then what? The politicians of all parties, Press and campaigners cannot see beyond fuel and electricity generation, so the "what" just does not occur to them.