Balcony Power Plant

Minor quibble:

>A 600 KW balcony power plant costs about 1100-1300 €, which means it will be amortized within 5 years. With a guarantee of 20 years, this corresponds to 4800 €. This results in a profit of about 3600 €, just like that!

This isn't a 600KW balcony power plant, it's a 600W power plant.

While imagining what the article might be about, I realized that there's a massive arbitrage opportunity in the residual pressure in municipal water service at the faucet outflow.