Solar Guide

This page contains helpful information on a variety of topics related to solar.

Scroll down or click on the appropriate link below for info on the following topics: 

Solar Basics

Curious whether solar is right for you? Not sure where to begin? Here are some helpful pieces of information to get you started. 

What ownership options are available?

Solar companies typically offer a few different ownership options: direct ownership, lease, or Purchase Power Agreement (PPA). A PPA consists of the solar company owning the array and selling you the electricity it produces. RMLD customers must lease or own the system; third party electricity sales to municipal utility customers (such as a PPA) are not allowed per MA state law. 

How do I know what size system I need? 

The system should be sized to roughly match the electricity consumption of the home or business where it is being installed. RMLD recommends that system capacity be no greater than 80-90% of the customer's kilowatt hour energy usage. The average residential system size in Massachusetts is 6.3 kilowatts (kW). This size system has the capacity to produce about 9,000 kilowatt hours (kWh) per year. Commercial system sizes vary. 

How do I know if my roof is right for rooftop solar?

The roof's structural and surface condition should be evaluated prior to installation to ensure repairs and/or replacement will not be needed in the near future. Roof orientation, tilt, and shading are also important considerations that impact a system's operating efficiency as well as a customer's eligibility for rebates. 

  • Roof orientation: south facing is best
  • Roof tilt: a 30-45 degree angle is best (this is typical of most New England homes)
  • Shading: ideally, a system should have no shade for a minimum of six hours per day (to qualify for the MLP Solar Rebate Program, shading must be less than 20%)

About how much will a system cost?

System cost will differ by size and installer. The table below illustrates the potential net cost of an average-sized residential solar system (6.3 kilowatts) after incentives, as well as the expected timeframe to achieve return on investment. 


Average cost per watt installed (MA)

MLP Solar Rebate Program

Massachusetts Tax Credit (lesser of the two)

2019 Federal Income Tax Credit

Net Cost After Incentives

2020 Federal Income Tax Credit

Net Cost After Incentives

MLP Solar
(<25 kW)









6,227 watts









Estimated Years to Achieve Positive Return on Investment




Are there any financing options are available?

Some customers may be eligible for a low-interest, fixed-rate loan through the Mass Solar Loan Program which is run by the MassCEC and the Massachusetts Department of Energy Resources (DOER). 

What happens to the excess electricity that my system produces? 

On clear days during the middle of the day when the sun is at its peak, your system is likely to produce more electricity than your home will use. In this scenario, you will be credited the monthly fuel charge per kilowatt hour for excess electricity fed into RMLD's distribution system. 

More Information

RMLD held a Solar Workshop on June 20, 2019. CLICK HERE to review the materials and watch the video. 

First Step - Selecting an Installer

If you've reviewed the basics and decided solar may be right for you, you're ready to take the first step: getting quotes and selecting an installer.

The Massachusetts Clean Energy Center (MassCEC) maintains a database of solar installers that have completed projects in Massachusetts. The tool can be filtered by county and provides the name of the installer, their median cost per watt, and the number of projects they've completed. Click here for MassCEC's Solar Cost Comparison Tool. It is recommended that you solicit at least three competitive quotes. The installer will determine the recommended size of the system based on your electricity usage. 

Once you've received quotes, the following steps are recommended:

Large municipal or commercial customers may prefer to issue a Request for Proposal (RFP). The US Department of Energy has created a Solar PV RFP Template that can be tailored to the needs of a particular business. 

Available Rebates

MLP Solar Rebate Program - for systems 25 kW or less (Residential and Small Commercial Customers)

Customers who install qualifying systems that are 25 kW or less in size may apply for the MLP Solar Rebate Program. All residential and most small commercial projects will fall under this limited-time program, which is funded 50/50 by the DOER and the RMLD. The amount of the rebate will be based on the size of the system installed, and equates to $1.20 per watt. Rebates are not to exceed 50% of the total installed costs of the system and are capped at a maximum of $30,000.

Examples of possible rebate amounts for qualifying systems:

  • 6.3 kW system = $7,560
  • 10 kW system = $12,000
  • 25 kW system = $30,000

DOER extended the program so applications can now be submitted through 6/30/2021, and all projects must be completed by 6/30/2022. Customers who installed systems with an operation date of November 27, 2018 or later may apply for the rebate. Energy New England (ENE) is administering the program on behalf of DOER and RMLD. Click here for complete program requirements

Commercial Renewable Energy Rebate Program - for systems larger than 25 kW (Large Commercial and Municipal Customers)

Customers who install qualifying systems that are greater than 25 kW in size may apply for the Commercial Renewable Energy Rebate Program. Most large commercial and municipal projects will fall under this program. The rebate is 50% of project costs and is capped at $50,000. Click here for complete program requirements

Rebate Pre-Approval

Regardless of which rebate you qualify for, it's important to know that you need to obtain pre-approval before starting installation in order to receive the rebate. Your installer will help you with this. MLP Solar Rebate Application step-by-step instructions may be found below. For more information on the Commercial Renewable Energy Rebate Program application process, CLICK HERE or call 781-942-6598. 

MLP Solar Rebate Program: Step-by-Step Application Instructions

All paperwork must be filled out in its entirety and all required supporting documentation must be included. Missing information could result in a delay in the approval process.

You must provide a valid email address as this is how you will receive all rebate related correspondence. All correspondence between RMLD and the DOER will go through the Program Administrator, Energy New England (ENE).

  1. Interconnection Review and Approval- RMLD’s Engineering Division must approve interconnection to RMLD's distribution system prior to system installation. 
  2. Apply for Rebate Pre-Approval- Apply for rebate pre-approval through ENE's rebate portal. You may proceed with this step while you are awaiting interconnection approval from RMLD.
    • Upload the following Rebate Pre-Approval Documents to the Rebate Portal (you will need your RMLD account number to apply):
      • DOER MLP Solar Program Rebate Application
      • DOER MLP Participant’s Agreement
      • Proof of Property Ownership (tax bill or copy of deed)
      • Shade Study (some DOER-approved shading analyses: Solmetric SunEye, Solar Pathfinder, Wiley ASSET Software, Aurora software with LIDAR data available, Bright Harvest, Scanifly)
      • Copy of Solar Contract between Homeowner and Contractor
      • Financial/Loan Documentation (if applicable)
      • Layout Sketch
      • Pre-Installation Site Photos
      • Tree Removal Attestation (if applicable)
  3. Receive Rebate Pre-Approval- ENE will forward the rebate application to the DOER for approval.
    • When a decision is made, the DOER will send the Rebate Award Packet to ENE. ENE will forward the packet to RMLD, the contractor, and the Customer.
    • Award Packet Contents:
      • Award Reserve Letter- Indicates the rebate amount and project completion deadline
      • Project Completion Form- This form will need to be completed in order to receive rebate payment
      • Change Request Form (if applicable)
  4. System Installation- When both the interconnection approval is received from RMLD and the Award Packet is received from the DOER, the system installation can begin. The installation must be completed within 1 year of DOER approval.
    • Prior to starting construction, the electrician must call RMLD at (781) 944-1340 to request a Utility Authorization Number (UAN)
  5. System Inspection- At the completion of the installation, a site inspection must be performed by the Town’s Wiring Inspector and the RMLD. 
    • Please send the following documents to
    • The approved Certificate of Completion and a Solar Permission to Operate (PTO) Letter will then be emailed to the customer.
  6. Final Rebate Documents- This is the final step in receiving payment.
    • Once the system is up and running, upload the following documents to the Rebate Portal to complete the application:
      • RMLD Permission to Operate Letter
      • RMLD Certificate of Completion
      • DOER Project Completion Form (provided in Award Packet)
      • DOER Change Request Form (if applicable - provided in Award Packet)
      • DOER Locus Meter Connection Form
      • Evidence Locus Production meter has been installed and is communicating (photo of the power-on meter showing the MAC ID)
      • Invoice from installer
      • Post Installation Photos
      • Updated Shade report and paid invoice from tree cutting service (if applicable)
    • You should expect to receive your payment within 90 days of the DOER receiving the final documents. Payment will come in the form of two separate checks from Energy New England.