Blackout Britain stories are not completely wrong, but they have entirely the wrong cause in mind. 

I have written before about how the reason the lights go out in the winter is because of bad weather and network outages (see The real failures on energy security), not because we don’t have enough power stations. Now we can add to that the times when we are oversupplied: it turns out that too much power is likely to be a problem more often than having too little power.