This story is showing in German right now at the website of Hans-Josef Fell, the former Green member of Parliament who was one of the authors of the German feed-in tariff.
It is about the experience of the small town of Hammelburg. It has a population of around 11,000.
In 1993, the local electricity provider decided to pay 2 German mark per kWh for solar electricity, up to a capacity of 15 kW, and finance that with a surcharge of 0.0015 mark (about 0.o7 cents Euro). A private company was founded and investors came up with 210,000 German mark (around 100,000 Euro). They installed solar panels and got their feed-in tariffs.
At the time, Hans-Josef Fell had high hopes. He thought in 1996 that Germany might be able to reach a whopping 80 MW a year if that principle of a feed-in tariff was extended to the whole country.
The actual success of this model was better by close to two orders of magnitude. It is interesting to look back and see that 80 MW a year was something people would value as a high number.
Now the solar panels at Hammelburg have worked for 20 years. And they are expected to work for at least another 20 years.
That’s another point worth noting. Solar panels are not going away once they are paid for (after twenty years). Those couple of kW in Hammelburg are among the first that celebrate such an anniversary. But they won’t be the last.
I leave it as an exercise for the reader to figure out what that means for the price of solar electricity (hint: it is much lower than what you’d get if you assume only 20 years of operation).