Commonwealth Solar II Rebates

February 04, 2015


Block 20 opened on October 7, 2014 and is the final funding block of the Commonwealth Solar II Program. See program website for more information.

Commonwealth Solar II, offered by the Massachusetts Clean Energy Center (MassCEC), provides rebates for the installation of photovoltaic (PV) systems at residential, commercial, industrial, institutional and public facilities.* Commonwealth Solar II rebates are available to electricity customers served by the following Massachusetts investor-owned electric utilities: Fitchburg Gas and Electric Light (Unitil), National Grid, NSTAR Electric and Western Massachusetts Electric. In addition, customers of certain municipal lighting plant (MLP) utilities are now eligible including Ashburnham, Holden, Holyoke, Russell, and Templeton. Commercial projects are eligible for rebates for PV projects less than or equal to 15 kilowatts (kW) in capacity and the rebate will be based on the first 5 kW only. Funding is released in "blocks" every quarter. All rebate applications must be approved BEFORE the project installation begins.

Rebate amounts are based on the total PV system size per building, regardless of the number of electric meters in use and certain other characteristics of the project. The proposed Commonwealth Solar II rebate levels for residential and commercial PV systems are:
  • Base incentive: $0.25/watt
  • Adder for Massachusetts company components: $0.05/watt
  • Adder for moderate home value: $0.40/watt (applicable to residential projects only), or
  • Adder for moderate income: $0.40/watt (applicable to residential projects only)
  • Natural Disaster Relief Adder (see program manual for detailed eligibility requirements): $1.00/watt
The rebate is available to the system owner, which may or may not be the host customer. In the case where the system owner is a third-party owner serving a residential host customer, the project is treated as a commercial project (and eligible for the commercial rebate amounts only). Solar renewable-energy credits (SRECs) associated with system generation belong to the system owner and may be sold via the Department of Energy Resources (DOER) SREC program. Note: appropriate, approved tracking must be utilized in order to qualify to sell SRECs. MassCEC reserves the right to conduct post-installation inspections of PV projects prior to approval for payments.

System installers are responsible for the application process and securing necessary permits. MassCEC has developed an online application system (called PowerClerk) for pre-approved installers. Only online applications will be accepted. An energy-efficiency audit is generally required. Required documentation generally includes electric utility interconnection approval, an energy-efficiency audit, paid invoices or equivalent, and, if applicable, evidence that automated reporting is functional. It is recommended, but not required, that installers or their subcontractors obtain or seek to obtain North American Board of Certified Energy Practitioners (NABCEP) PV installer certification.

This summary does not capture all of the requirements of the Commonwealth Solar II program. The MassCEC provides program manuals as well as appendices with full program requirements and you must read those materials carefully.
The Commonwealth Solar II program summary report provides an ongoing tally of number of systems and kW installed in the state. The Commonwealth Solar II Program will end once funding for Block 20 is fully expended.


Program Overview

Implementing Sector: State
Category: Financial Incentive
State: Massachusetts
Incentive Type: Rebate Program
Web Site:
Administrator: Massachusetts Clean Energy Center (MassCEC)
Start Date:
Eligible Renewable/Other Technologies:
  • Solar Photovoltaics
Incentive Amount: Residential: $0.25 (base) - $1.70/W DC (varies by rebate adders)
Commercial: $0.25 (base) - $1.30/W DC (varies by rebate adders)
Maximum Incentive: Residential: $3,500; Commercial: $1,500 (per host customer and excluding natural disaster relief adder)
Eligible System Size: 1 kW (minimum) up to 15 kW (DC)
Equipment Requirements: All equipment must be new, UL-listed and compliant with IEEE standards. Modules must be certified to UL 1703 standards. Inverters must be certified to IEEE 929 and UL 1741 standards. All modules, inverters, and production meters must be on the California Energy Commission's list of eligible equipment. Automated reporting encouraged for systems over 10 kW. Minimum manufacturer warranties required: 5 years product and 20 years performance for modules; 10 years for inverters; 2 years for revenue grade production meters; and 5 years for mounting equipment.
Installation Requirements: Projects must be installed in compliance with all local, state, and/or federal building and electrical laws, codes and practices. Electrical work must be performed by a Massachusetts licensed electrician. NABCEP certification recommended. Projects must have a minimum 5-year warranty provided by the installer against defective workmanship, project or component breakdown, or degradation in electrical output of more than 15% from original rated electrical output during the warranty period.
Ownership of Renewable Energy Credits: Remains with project owner


Name: Commonwealth Solar II
Organization: Massachusetts Clean Energy Center
Address: 55 Summer Street, 9th Floor
Boston MA 02110

This information is sourced from DSIRE; the most comprehensive source of information on incentives and policies that support renewables and energy efficiency in the United States. Established in 1995, DSIRE is operated by the N.C. Clean Energy Technology Center at N.C. State University.