Gas power generation is a necessary evil to balance out the variability of intermittent energy generation (i.e. wind and solar).
Hydropower isn't a feasible alternative because the easy resources have been developed.
The only alternative source of flexibility available today is demand side response.
Edit: I appreciate the down votes, as I've not explained in detail. It is a complex issue. My opinions are based on having a phd in the topic, 10+ years in control rooms, years of market operations and design, and years contributing to europe-wide risk assessment methodologies.
I emplore anyone who is actually interested in how energy mix actually impacts grid stability/reliability to look into the Eirgrid DS3 programme (https://www.eirgrid.ie/ds3-programme-delivering-secure-susta...).
If prices continue to drop, there will be a powerwall alike in every second house in some years.
The UK is forging ahead with large scale battery storage projects. I have not done the math, but I assume there is a sound economic case in order for these projects to receive this level of investment.
Edit: Here's some more data on revenue for battery storage in the UK [3]
[1] https://www.solarpowerportal.co.uk/battery-storage/statera-u...
[2] https://www.solarpowerportal.co.uk/battery-storage/fidra-ene...
[3] https://modoenergy.com/research/gb-research-roundup-january-...