The electricity flickered in the basement offices at the Calvary United Methodist Church at 48th Street and Baltimore Avenue last week, and the heat wasn't so reliable either. But Brandy Doyle and Maggie Avener of the Prometheus Radio Project, bundled in heavy clothes, weren't complaining.

After about a decade of lobbying and community organizing from these humble poster-filled rooms in West Philadelphia, Prometheus Radio finally had scored with federal legislation that will legalize hundreds of, and perhaps as many as 2,000 to 3,000, low-power FM radio stations in cities and rural markets.

The seven-employee nonprofit group seeks to diversify what it views as generic radio content resulting from corporate ownership with low-power FM stations. Prometheus argues that even low-power FM stations can force full-power commercial stations to pay more attention to local news and content.

The Local Community Radio Act of 2010 passed the House on Dec. 17 and the Senate on Dec. 18 and is awaiting President Obama's signature. Matt Dinkel, the communications director for Rep. Mike Doyle, a Pittsburgh Democrat and a lead House sponsor of the legislation, said: "That's going to happen. It's just a function of when."

When it does, the Federal Communications Commission is expected to develop rules for adding the new low-power stations to the FM radio dial. There could be three to seven added in the Philadelphia area, depending on the FCC rules, officials said.

The Local Community Radio Act was a hard-won victory for Prometheus and the Washington nonprofit group Free Press, both of which have lobbied against media consolidation in TV, newspapers, and radio. While Free Press has more broadly attacked media consolidation, Prometheus has mostly focused on radio and considers itself the nation's leading advocate for low-power FM stations.

"We are thinking of low-power radio as something that revitalizes radio all around," said Avener, a broadcast engineer and Prometheus employee. "We are going to make sure the licenses are available in every city and then build those stations."

Passing the radio act was not easy. Prometheus was founded by former radio pirate Peter Tridish, who operated a West Philadelphia station without a license in the mid-1990s. His real name is Dylan Wrynn, but Tridish was how he was known on his pirate radio show. Prometheus formed alliances with religious groups to overcome opposition from full-power radio stations that warned of airwave clutter and station interference. A government-funded study largely debunked the interference argument several years ago.

Dennis Wharton, executive vice president of the National Association of Broadcasters, said Thursday that the trade association supported the radio act after it included station-interference protections and noted that commercial radio was the "primary provider of radio service in a community."

Clinton-era FCC Chairman William E. Kennard first considered licensing low-power stations in the late 1990s and began doing so in early 2000. But Congress subsequently limited the program to rural areas and called for an interference study in midsize and big cities.

Broadcasters "didn't want to see more radio stations on the dial," Tridish said. "They were thinking back to the 1940s, when everybody listened to the radio and they had a sense of entitlement to that audience."

Tridish expects the FCC to evaluate the new law in 2011 and then allow groups to apply for licenses during a five-day application window, possibly in 2012.

Low-power FM stations do not seem a threat to commercial radio stations. They will not broadcast advertising and typically reach three to five miles. The low-power stations fit on the radio dial between the commercial stations.

For groups awarded a low-power FM license, building a low-power station is affordable - about $7,000 to $60,000. The difference in costs is related to studio quality, Tridish said. The electricity costs to operate the station transmitter are about the same as lighting two 100-watt lightbulbs, he said.

With the new legislation authorizing the stations, Tridish expects Prometheus to expand modestly as it works with the FCC on low-power regulations and educates groups on how to apply for licenses.

Prometheus Radio states in its IRS tax document that its mission is "to create a more democratic media."

The group had expenses of $296,231 in 2009, and assets of $194,955, according to its latest Form 990 with the IRS. It rents offices in the church basement, sharing it with a karate class and a day care. Tridish was paid $19,880 as the executive director. Prometheus' seven employees, including himself, earn the same compensation, Tridish said. "It's been a great formula for us - all of us making the same wage."