The price of electricity in the UK is because of the price of LNG due to the war in Ukraine. Without North Sea wind power reducing the demand for LNG electricity would be even more expensive.
Its always worth playing with iamkate and looking at what the current power mix is and what it has averaged over the last year and how prices correlate with green energy.
As with everything else, the marginal cost of additional renewable energy and storage will rise. At some point, all the low-hanging fruit is picked; there are only so many locations suitable for wind farms and pumped hydro. It's fallacious to think that the £0.15/kWh price will hold as it gets scaled up to meet more of the demand.