so far i've moved floor heating, hot water, and car charging entirely to solar (see chart and its alt text).
not sure there is much left to cut: especially with always-on systems like ventilation and my local network
@hi yeah at this point you just need to run the numbers on battery storage & installation/cabling/etc.
Modern lithium cells are rated for over 8000 cycles (that is, they retain over 80% capacity AFTER so many cycles) so daily cycling when charged from solar excess and running at night will still mean they should last you well over ten years.
Even a tiny, simple, easy-to-install system can make a huge difference on a 10-year timeframe: my homeserver, network etc. uses roughly 1kWh in a day, it's hooked up to an Ecoflow River 3 Plus acting as a UPS. If you can power & charge that from your existing solar excess (planning to add some balcony solar) that will recover your investment in 5 years or less (costs 260 EUR, assuming 0.13c/kWh average electricity price over 2000 days to ROI)
https://www.hind.ee/p/kaasaskantav-akujaam-ecoflow-river-3-plus-286-wh-600-w-must/