I already spent what felt like 2 hours reading all the posts here, and I also want to briefly share my opinion on the amortization. But first, a quick word on physics: electrical power is measured in watts and capacity (amount of current) accordingly in power x time, so Wh. For the power of the systems and storage described here, we are therefore talking about kW and kWh. Please be accurate, after all, we are not Angela Merkel, who talks about energy production. That makes me sick, because every schoolchild learns in 5th grade that energy is not produced but only converted. Back to the topic: Since I am an eco-friendly person, I find electricity storage a great thing, if you ignore that enormous resources of valuable elements are built in here. Large pumped-storage power plants are more ecologically sensible! From an economic perspective, things look even worse. As the operator of 2 small photovoltaic systems and a mini combined heat and power plant, I would have top conditions to permanently charge and discharge the storage, at least 300 days a year. Calculated with a 10 kWh storage, I could store 1700 kWh per year and, with 90% efficiency, therefore reuse 1530 kWh. The difference between the feed-in tariff of about 12 cents and electricity purchase of about 23 cents net (I am a commercial user) is 168.30 euros. Assuming the storage lasts 20 years—that is, 6000 charge cycles—then I would save 3366 euros. For a private user, who settles everything in gross and maybe can also increase the storage capacity, a few euros more come into play. But from a business perspective, the investment costs should not exceed the savings, I would say...