The Kennebunk Light & Power District has entered into a 20-year agreement to support development of a large solar array on district property.

The power purchase agreement calls for DG Maine Solar LLC to design, permit, construct, operate and own the 2.9-megawatt solar array, which will be constructed adjacent to the district’s West Kennebunk substation. The district’s board of trustees said commercial operation of the array could begin as soon as the fall of 2018.

DG Maine Solar is a subsidiary of NextEra Energy Resources LLC, which is headquartered in Juno Beach, Florida.

Initial estimates project that the solar array will produce 3.9 kilowatt-hours during its first year of operation, or just under 4 percent of the district’s annual kilowatt-hour sales.

Kennebunk Light and Power District’s trustees initially received several unsolicited offers for the design and construction of a solar array. After reviewing the offers, trustees determined that it would be in the district’s best interest to seek official proposals.

In June 2016, the district advertised for proposals and received four from different solar providers. General Manager Todd Shea reviewed the proposals and the trustees selected DG Maine Solar at their October meeting. They approved the power purchase agreement at their April 25 meeting, the district said in a statement last week.

“Pricing for the solar power is actually lower than the cost to purchase energy off the grid due to the lack of regional network and local network charges that are added to the cost of energy that must be delivered from outside of the District’s territory,” the statement said.

The agreement gives the district the ability to expand the system so long as the power generated does not exceed system consumption for the West Kennebunk substation.

Kennebunk Light and Power District is a consumer-owned utility that was founded 1893.