What was so significant about Saturday 25 March 2017? According to the National Grid, it was the first time demand for electricity in the sunny afternoon fell below what it had been during the night before.
So Saturday 25 March was the day all those little PV arrays on all those houses across the UK kicked in to produce so much power that the Grid didn’t need to generate as much as it had during the night. It’s not easy to calculate what that total production was, because when the sun shines on your house all that happens to the Grid is that it registers a small reduction in demand – and it has no way of knowing what that demand might have been if there hadn’t been a burst of sunshine at that time. What the National Grid knows is what the big producers are doing in response to fluctuations in demand; but you and me, we just use what we produce first to reduce our demand for electricity from the grid, then if we have more than we need, export it to the Grid, where it doesn’t make that much difference to the power washing around the country. And on Saturday March 25, 2017, for the first time ever, the reduction in central demand as a result of us all using our own electricity (produced by those thousands of solar installations) meant we needed less coal or gas or oil than we did in the middle of the night before.
So remember that day, and say “I was there. I did that – or at least, I was a part of that. I did my bit.”
Full story here. And hear it explained by Robert Llewellyn below