Auburn’s Wastewater Treatment Plant has a couple of new additions to feel sunny about.

On Tuesday the city unveiled its new solar power project and ultraviolet disinfectant system to the public.

An overflow reservoir just outside the plant’s processing center is now home to over 4,000 solar panels that rotate 45 degrees to track the position of the sun.

The city entered into a leasing agreement with Auburn company Pacific Power Renewables, which owns and operates the new solar array.

Instead of paying a PG&E bill, the city now receives its power from Pacific Power Renewables, which saves the city money on its annual cost, said Bernie Schroeder, director of the Auburn Public Works Department.

“We believe based on last year, and what we have been guaranteed by Pacific Power, that we are going to be able to reduce our annual cost of power by 10 percent,” Schroeder said. “It could be more.”

As a result of the agreement, the city did not have to pay for the installation of the solar panels.

David Dwelle, president of Pacific Power Renewables, said the solar array also generates more than enough power for the plant, including supporting the new disinfectant system.

“We are generating electricity from the sun, and we are generating about two-and-a-half times what the city is using for the plant,” Dwelle said. “Overall we think it’s going to cover the bill for the city for the entire year.”

Dwelle said the power still runs through the PG&E grid, and any extra power generated is sold to PG&E by Pacific Power. Then the company re-purchases it for the plant as needed during non-peak hours.

Dwelle said there is a monitor at City Hall that shows how much power the system is generating and how much the facility is using.

Councilman Kevin Hanley said the idea for a solar project at the plant started in 2006 when the city became aware that it would have to use UV lamps instead of chemicals to disinfect the water. In January 2007 the council approved the “Auburn Solar Initiative.”

After a multi-year debate on whether the city should upgrade its plant or participate in a regional sewer line, the city decided to upgrade and began the solar project, Hanley said.

The ultraviolet disinfectant system is replacing the old chlorine system the plant used in the past and was part of a $6 million upgrade required by the State Water Quality Control Board, Schroeder said.

The upgrade brings the plant into compliance until 2015, Schroeder said.

According to Schroeder, without the upgrade the city would have faced $30,000 a month in mandatory minimum penalties.

Mike Harrison, a design engineer on the project with Stantec in Rocklin, said there are several benefits to moving from chlorine to UV disinfectant.

“When you add chlorine to wastewater it creates what is called chlorine byproducts,” Harrison said.

These byproducts can be harmful to people and can cause fish kills if they get into the river, Harrison said.

“Removing chlorine removes the possibility of any fish kills, and it removes those chlorine byproducts,” he said.

Mayor Bill Kirby said he thinks there are several benefits to the solar power, including reducing the amount of money spent to run the plant and residents not having to pay for the project.

Kirby said the upgrades give the city more time to decide whether or not to participate in a regional sewer line.

“It puts Auburn in the best possible position for the debate,” Kirby said. “It puts us in the driver’s seat as far as negotiations because we are in no rush.”

Hanley said he sees the installation of the solar panels as a triple-win.

“No. 1, it will save Auburn sewer ratepayers up to $1.3 million through the power purchase agreement we signed with the company,” Hanley said. “No. 2, it’s good for our environment and energy independence as we use less fossil fuels, and 3, we were able to contract with an Auburn-based company.”

Reach Bridget Jones at bridgetj@goldcountrymedia.com