The other energy sources were able to fill the supply gap, now aside from the UK government botching (to an astonishing degree) the build of new nuclear power stations, you would have to time travel back over 40 years to the start of the coal scale back and convince people that the USSR was going to collapse and invade itself resulting in disruptions to supplying Europe with natural gas. Given that, at that point in time, Ukraine was still part of the USSR (as was Russia), they supplied Europe with zero Natural Gas (because Cold War), and the UK had ample Natural Gas of its own, and abundant gas storage in place, you would have been considered quite, quite mad and laughed out of the room.
Applying contemporary hindsight to the events of the last century is absurd.