Current and projected cost of storage is relatively high, the most cost efficient storage is hydro and compressed air, they are not showing any kind of fast decrease in cost.
Maybe there is potential in energy grids that span continents and have large over-capacity - then you dont need much storage.
I am assuming we are talking about imminent future, in 50 years maybe math is different, but thats too late for climate change.
Nuclear power has always been a government funded energy source so unless government policy changes and UK orders 50-100 of these power plants by 2050 then nuclear power is not going to make any difference. Convincing all governments on the planet to invest into nuclear power is extremely unlikely. Without the introduction of a CO2 tax nuclear power will always look bad vs coal and coal will always look bad vs renewables and from what I can tell the vast majority of people don't want a CO2 tax even though it would be the best solution for climate change.