ASHLAND — The city of Ashland has expanded its landmark policy on selling excess power from residential solar panels in order to encourage large-scale projects.

People could receive credit on their electric bills for systems up to 25 kilowatts by feeding the extra electricity back into the city electric grid.

Now the Ashland City Council has raised the level to 50 kilowatts because more home-owners and businesses may be taking advantage of federal and state tax incentives to install bigger systems, said Ashland Electric Department Director Dick Wanderscheid.

“We’re hearing some systems may go in that are over 25 kilowatts. The largest one we’ve heard of that’s being planned is 32 kilowatts,” Wanderscheid said.

Some people may be racing to install solar systems because of uncertainty over whether Congress will reauthorize federal incentives for solar that expire at the end of this year.

Several reauthorization bills have been introduced, but none have passed so far, Wander-scheid said.

He estimated that 42 net- metered solar systems in Ashland are connected to the grid.

Ashland first passed a net metering policy in 1996, making it the first community in the Northwest to pay solar system owners for their extra electricity. Since then, other Northwest utilities have followed Ashland’s lead, Wanderscheid said.

In 2005, the amount of solar electricity connected to Ashland’s grid doubled to 66 kilowatts after the city increased the amount of money it gives as rebates to people who install solar.

The amount connected to the grid doubled again this year to at least 140 kilowatts.

People who take part will receive annual credits on their energy bills that equal the value of the electricity their panels generate.

The payback is estimated to be up to $425 over 20 years on one panel — or about half the amount a person invests.

Solar systems for the typical home range from about $13,000 to $32,000, although city rebates and state and federal tax credits reduce the final cost.