The surge of interest in the payment system is a recognition that despite generous state and federal incentives, the United States still lags far behind Europe in solar power. Germany, where feed-in tariffs have been in place since 1991, has about five times as many photovoltaic panels installed as the United States, though they still account for only 0.5 percent of electricity in that country.

In the United States, said Wilson Rickerson, a Boston energy consultant, “a lot of people simultaneously reached the conclusion  who’s moving fastest internationally? And that’s definitely been Germany and Spain.”

In Gainesville, the new policy has already sparked a rush to put up panels. John Stanton, a retired civil servant living there with his wife, put 24 solar panels on his roof in late January, as city leaders sped the policy toward approval. Gainesville’s municipal utility will pay Mr. Stanton and other homeowners and businesses who generate solar power more than twice the standard electricity rate, guaranteeing that rate for 20 years.

“It was the thing that sort of put us over the top,” said Mr. Stanton, who gained an appreciation of European energy policies after living in Italy for more than a decade.

Mr. Regan said that homeowners with panels received a payment under the new policy that works out to more than a 25 percent premium over the city’s other incentives, which include rebates and a more modest rate payment.

Wind power and other sources of renewable energy are generally included in the European payment systems, but solar  as one of the costliest renewables  has benefited the most. Payment rates in Europe for wind are substantially lower than for solar, according to Christian Kjaer, chief executive of the European Wind Energy Association.

Image Homes with solar panels in Germany, where homeowners are paid to produce green energy. Credit... Karl-Josef Hildenbrand/European Pressphoto Agency

In the United States, solar panels remain prohibitively expensive  a big reason that the panels account for far less than 1 percent of electricity generation. Generating power from the sun using rooftop panels can cost four times as much as coal, the largest and cheapest source of electricity in this country.