By tapping the daylight for electricity -- which power companies are obliged to buy for 20 years at more than triple market prices -- they are at the vanguard of a grassroots movement in the fight against climate change.
"It's grown much faster than anyone thought it would," Juergen Trittin, the former Environment Minister who masterminded the scheme, told Reuters. He was mocked at the time for his claims it would create jobs and not hurt the economy.
There are now 250,000 jobs in Germany in the renewables energy sector. Asbeck expects the number of jobs in solar power alone to double to 90,000 over the next five years and hit 200,000 in 2020.
The law has also since served as a model for other countries including Spain, Portugal, Greece, France and Italy.
GUARANTEED PAYMENT
Germany's photovoltaic systems generate about 3,000 megawatts of power -- 1,000 times more than in 1990.
Asbeck said political decisions in the 1990s made it easy and even lucrative for ordinary people to put the systems on their roofs.
At the heart of the scheme is a "feed-in tariff" giving anyone who generates power from solar PV, wind or hydro a guaranteed payment from the local power company. The power firms are obliged to buy solar electricity for 49 cents per kilowatt hour -- or nearly four times market rates.
This can work out at a better return than putting money in the bank. So despite the cloudy weather, the investment pays for itself within 10 years.
There are some critics of the solar power incentives who want the government to phase out the programme faster than now planned. The lucrative feed-in-tariffs are, however, guaranteed for 20 years for all existing owners.
Gerhard Mueller-Westermeyer, a climate researcher at the German national weather service (DWD), said most of Germany is covered by clouds between five and six eighths of the time and there are only a handful of days each year with no clouds at all. Many German towns have annual sunshine of some 1,500 hours -- about half as much as in Spain.
"Obviously, there would be a better return on solar panels set up in sunnier places like Africa," he said. "But the energy would have be transported and that's difficult. So it makes sense to build solar panels where people need them."
