Comment by LeonM

I found most people fixate on the price of the cells/panels, but forget that the rest of the installation required to use said panels easily exceeds the price of the panels by a factor of 3~4. Think mounting hardware, cabling, inverters, batteries, control hardware, labour, etc. It all adds up.

I've been pricing a PV system recently, and I was surprised at how low the price of panels already is. In most estimates I received the panels itself were less than 20% of the total installation costs. Granted, I am looking at a 3-phase system with plenty of battery capacity. For a more typical household setup with 1-phase and moderate battery capacity that percentage will shift a bit.

In my case the quotes are roughly: 40x430Wp panels (~€4000), 3x (3-phase) inverter/chargers (~€5000), batteries (~€5000), auxiliaries (~€1500), cabling (~€2000), mounting hardware (~€2500), labor (~€5000), planning/permissions (~€1000). So total project price is ~25k, of which the panels are only ~€4000. And that doesn't even count the construction of a utility building to house the batteries and inverters, the EV chargers, etc.

On a side note: I found that battery prices have also dropped significantly already. If you're willing to do some assembly yourself you can get ~15kWh of LiFePO4 for just over €1k.

Also, for those wondering: for my situation the ROI of this setup is expected to be about 5 years. This will be quicker if I get an EV, which I am planning on.