Thats coz when we max out renewables 40% of electricity still comes from gas. Theres literally zero point in storage until renewable generation starts edging towards 100% at least sometimes.

Investment has started though - there's coire glas, which is taking about 5 years to build. 5 more of them and we could go 99% renewable on solar and wind alone.

A substantial proportion of renewable capacity is already lost to curtailment in the UK, and supposedly this could be reduced by storage. This happens well before renewable generation hits 100% even some of the time for various reasons (transmission capacity bottlenecks, the need for a certain amount of dispatchable power to ensure grid stability, and so on).

All time high is not enough for a war situation.