Norwich — The former Stott family dairy farm's conversion into a fully functioning 15-acre solar panel field operated by Norwich Public Utilities was hailed Wednesday during rain-soaked ceremonies as a landmark for the region and state.

The 4.7-megawatt solar storage system at Mountain Ash Solar Farm on Stott Avenue, which sits near Dodd Stadium and across from a cornfield, is the largest solar and energy storage system in Connecticut, and is not expected to add costs to local power bills.

When combined with hydroelectric power already generated in the city, residents here will obtain nearly 20 percent of their electricity from renewable sources, said John Bilda, general manager of NPU.

The project is expected to supply the full annual electrical power needs of more than 8,400 homes over the next two decades.

"This to me is a real milestone to how renewable energy will work in the future," said John Conley, vice president of project development for SolarCity, the clean-energy company that financed the project.

Mayor Deberey Hinchey praised the public-private partnership that brought about the project, which includes more than 15,000 solar panels.

In addition to NPU and SolarCity, the solar farm was brought to life by the Connecticut Municipal Electric Energy Cooperative — a consortium of municipal utilities that include Norwich, Groton, Bozrah and Jewett City — as well as Brightfields Development, which completed the project's construction.

"This project is a great source of pride to the city of Norwich and Norwich Public Utilities," Hinchey said.

"We all know renewables are the future," said state Sen. Paul Formica, R-East Lyme, ranking member on the legislature's Energy and Technology Committee. "It takes this type of collaboration."

U.S. Rep. Joe Courtney, D-2nd District, pointed out that the project was made possible thanks partly to $25 billion in federal energy tax credits pushed through Congress toward the end of last year.

It is one of six renewable-energy projects being completed or planned by the municipal energy cooperative, said CMEEC Chief Executive Drew Rankin, including one other in Norwich, one in Bozrah and three on Navy land in Groton.

When storms hit, he said, "It's another local generation source to keep the lights on and power flowing."

Michael Singer, principal of Brightfields, said the project included the installation of 1,800 posts, 6,000 pieces of racking and five miles of wiring, not to mention five transformers and six inverters, plus battery storage.

This project was the first ever using SolarCity's new GridLogic control platform, which provides public utilities with the ability to instantly use battery-stored solar energy if there is sudden increased demand, such as a power outage.

The storage system can provide up to 3,000 kilowatt hours of electricity.

The utilities cooperative has a 20-year purchase agreement with SolarCity to use the energy from Mountain Ash Farm at a fixed rate for capacity, stabilizing customer rates.

"It's energy businesses can afford to purchase and move into this area," said state Sen. Cathy Osten, D-Sprague.

In Norwich, the other solar power installation being completed is at the Roger's Road landfill, where SolarCity is leasing about five acres for a project about half the size of the former Stott's Farm property.

Rankin called the Stott Avenue project "groundbreaking" and thanked Kelvin Stott and his family for providing the land to make it a reality.

"For seven generations, the Stott family operated a successful dairy farm at this very location," he said in prepared remarks. "It is our hope that this project enjoys the same longevity as we provide thousands of Connecticut residents and businesses with clean and renewable energy for years to come."

l.howard@theday.com