I recommend everyone who is using the cost argument to actually do the math on this first. It might be an eye opening experience. It certainly was for me.
1. This calculation takes into account that there is no exchange with mainland europe and no gas power plants or other sources of power (e.g. hydro or hydro storage). This sharply reduces the need for batteries. 2. Battery costs will fall in the next decades, compared to nuclear, which will take a long time (if ever) until costs will fall.
[1] https://www.statista.com/statistics/322874/electricity-consu... [2] https://docs.nrel.gov/docs/fy25osti/93281.pdf
In practice there are never long periods with and zero wind and zero solar and zero import capacity. Place the right price on electricity during peak demand, and suddenly the market is more than happy to install an overcapacity of wind & solar. Gigawatt-capacity cables to neighboring countries? Already being built!
A country like the UK needs an average electricity input of 45GW. It is totally fine to serve that with 60GW of wind operating at 25% capacity, 60GW of solar operating at 25% capacity, and 15GW of import operating at 100% capacity.