BERKELEY — Kevin Gage, a sales manager for Borrego Solar, which has an office in Berkeley, said the company installs about 20 solar systems in the city each year.

But since the Berkeley City Council late Tuesday unanimously approved a first-of-its-kind program to help property owners with the cost of installation — by tacking the cost onto their property-tax bills over a 20-year period — that number could soon balloon.

A deal with a bank or private-investment firm to finance the project still needs to be worked out, but the new plan is a giant step forward in meeting the city's lofty goal of reducing greenhouse gas emissions by 80 percent by 2050, city officials said.

"I really think that there is a huge advantage, especially in this current financial market," Gage said. "If a city, with their leverage and their security, can get this money, it seems like there is very little risk in that because they have the collateral of the whole home. If you were a lender, you'd be more secure in giving to a city than a single person. It's a great way of financing for renewable energy that benefits everybody."

The plan was crafted after more than 80 percent of voters in November 2006 approved Measure G, making Berkeley the first city in the nation to ask every man, woman and child who lives or works in Berkeley to do their part to reduce the city's carbon footprint.

With an 8-0 vote Tuesday night, the city approved the Sustainable Energy Financing District. This special tax district will enable property owners to install solar systems because Berkeley would pay all the upfront costs by borrowing a lump sum of money.

A pilot program will require about $1.5 million to finance about 50 homes.

Each system is expected to cost about $20,000 to $22,000, with homeowners paying about $182 monthly on their property tax bills. If all goes as planned, property owners could recoup some of the money from savings on their monthly energy bills, city officials said. Property owners will be charged interest, but the rates will likely be lower than what a bank would charge.

In a city staff report by Deputy City Manager Christine Daniel, it says there are about 4,000 homes in Berkeley that could benefit from having solar systems on their rooftops. There are roughly 25,000 residential and commercial properties in Berkeley, Daniel said.

But Gage thinks it could be more. "Anyone who has a roof facing southeast to due west would have a good roof for solar. If you have a lot of trees, that might be a factor, but there is increasingly more and more technology that can harvest more energy from sites that have shading from trees."

City leaders have had queries about the framework of the program from Hawaii to Massachusetts as well as from Europe and Asia.

Kristin Bender covers Berkeley. Reach her at kbender@bayareanewsgroup.com. Read her blog at www.ibabuzz.com/outtakes.