Energy storage is relatively easy, you just need to appreciate that there are losses in the conversion process. There are some days where we do generate an excess on top of the baseload that we currently get from Nuclear and the limited coal Powerstations (mainly Drax). Once up and running the production and storage of green hydrogen is pretty simple. Likewise liquified compressed air, the ideal place to store it is underground and seen as the coal mines aren’t producing much coal these days…
https://www.theguardian.com/environ...-liquid-air-battery-starts-construction-in-uk
You are right about coal, the UK were leaders in low carbon emission coal plants but a decision was made to decommission them because gas was seen to be cleaner and cheaper.
The issue of energy security has never been high on anyones agenda until now. For the suppliers it’s been about maximising margins and from a government point of view, placating the oil and gas producers.