"cheaper electricity at night"
That might not be the case.
If we have a lot of electric cars, they might be gobbling all night. Solar panels will be dark. If demand equals or exceeds supply, there is no reason for prices to drop.
At times when there is plenty of wind, we'll get quite a lot of wind power, which will sell into any market for whatever price it can get. Wind installations are constantly getting cheaper.
However, if our nuclear plant ever gets finished, we have foolishly committed to pay way over the market price, with a price escalator to help the French and Chinese owners get rich at our expense. So nuclear power will not be cheap at night or at any other time.
This link is interesting.
At the time of writing, national demand is about 27.7GW. That's a night-time low, it doesn't go much lower.
On a windy day, windpower can give between 5GW and 10GW. But at the moment it is only giving 1.1GW, and has been low for a couple of days.
Our remaining nukes are giving 6.8GW (near their max); coal and solar nothing; hydro almost nothing.
More than half our electricity is coming from large gas generation, giving 15.5GW
We are importing a bit, mostly from French nukes.
Our peak winter daytime use is about 40GW
All being well, we can meet that if we fire up some old coal stations, and some small, inefficient gas generators that are kept as backup.
If the event of a gas shortage, we're stuffed. The government thinks it more economical not to pay for a reserve store of gas, and there is no private operator willing to pay for it.