Surfside Wastewater Treatment Plant Solar Project

On July 21, 2023, the Town of Nantucket energized its first municipal solar project at the Surfside Wastewater Treatment Facility—the island’s second largest consumer of electricity.

The 104.4-kilowatt (DC) rooftop solar array, installed by local company ACK Smart Energy, consists of 232 solar panels and was funded primarily through a $200,000 Gap Energy Grant from the Massachusetts Department of Environmental Protection’s (MassDEP) Clean Energy Results Program. This grant, awarded to the Town’s Energy Office in 2019, fills critical funding gaps that often prevent clean energy projects from advancing at the local level.

In its first year of operation, the system produced 150.32 megawatt-hours (MWh) of electricity, offsetting approximately 6% of the facility’s electric load and 106 metric tons of greenhouse gas emissions. The project has resulted in an estimated $30,064 in avoided electricity costs in its first year alone.

Thanks to a combination of state grants, federal tax incentives, and utility rebates, the project achieved an immediate return on investment, generating savings from the outset with no upfront cost to taxpayers. In addition, the array participates in the Massachusetts SMART solar incentive program, which provides ongoing revenue to support future Sewer Department capital and maintenance needs.

On May 5, 2025, the Town of Nantucket received a $71,894 payment through the Elective Pay (Direct Payment) provision of the Federal Clean Energy Tax Credit, established under the Inflation Reduction Act. This payment included the Town’s full $64,969 cost share—representing 25% of the project’s total cost—and an additional $6,925 in interest to account for the year-long processing delay following the original IRS filing in May 2024.

Click to view the system’s energy production and performance!

Financial Information

The estimated electrical energy savings is over $35,000 per year. After factoring in grant funds, tax rebates, and utility incentives, the Town anticipates an immediate return on investment/payback period for the solar system.

Additionally, with the project’s participation in the Massachusetts SMART solar incentive program, the project will generate additional revenue for the Sewer Department to help fund future capital and maintenance projects.