Solar Panels and Batteries

(last update: 3/10/26)

Installing SOLAR in Concord

18 slides on: 

  • Financial, environmental, & energy independence benefits of solar
  • Siting decisions and, if you move ahead, steps in the process
  • Ways to learn, do, give, and ask more on these topics

Net Billing in Concord for Solar and Batteries

The Basics - 10 slides explaining Time of Day rate variables and how to read your bill

The Details - 6 slides explaining net usage within each hour, using your solar array and/or batteries to save on your bill, and determining how much electricity you used in a month

Rebate

CMLP Solar PV Rebate: $625 per kW(DC) of installed solar PV generation capacity, capped at $3,125 per service address.  Residential installations up to 167 kW(AC) and commercial installations of any size are eligible.  You may choose to have CMLP issue the rebate to the electric account holder or to the project installer.  There is no expiration date anticipated for this rebate.

Steps to Install Solar and/or Storage

A. Explore Options & Sign a Contract:

  1. IMPORTANT NOTE: If your property already has or you are considering installing a sub-meter (such as for an EV (electric vehicle), winter electric heating rate, etc.) please read this page and its sub-pages to familiarize yourself with the options and trade-offs when combining sub-meters with solar panels.
  2. We recommend that you solicit proposals from at least three solar installers for your new solar PV system.  You’ll find information to help you with this step at our Lease/Buy/Choose an Installer webpage.  People who’ve already installed solar are also a good source of information about installer performance.  Check online reviews, talk with people you know, or ask CMLP’s Energy Specialist Pamela Cady (pcady@concordma.gov or (978) 318-3149) to put you in touch with Concord homeowners or businesses who’ve installed solar and volunteered to coach others.
  3. When soliciting proposals from solar installers, tell them you are interested in applying for the CMLP Solar PV Rebate.  Confirm that they’re familiar with the CMLP Solar PV Rebate and interconnection requirements outlined in step B below.
  4. Paired storage: Current CMLP electrical distribution system limitations may preclude the installation of medium or large solar arrays without an accompanying energy storage system
    1. Medium scale systems: Total solar capacity 25-50 kW (AC) 
      Decisions are made on a case by case basis after engineering review
    2. Large scale systems: Total solar capacity >50 kW (AC)
      1. If prior solar capacity at the site is under 50 kW(AC) and more solar is added, battery capacity must be paired with any solar capacity in excess of 50 kW(AC). The battery capacity must be capable of storing 4 hours of electricity produced by any solar capacity in excess of 50 kW(AC), at its peak solar electricity production potential.
      2. If prior solar capacity at the site is over 50 kW (AC), battery capacity must be paired with any new solar capacity added. The battery capacity must be capable of storing 4 hours of electricity produced by your new solar capacity, at its peak solar electricity production potential (AC).
      3. In both instances, CMLP must be able to control the times of battery charging and discharging.

B. Installer Emails Interconnection Application with Related Documents to CMLP:

  1. Residential or Commercial Interconnection Application, with or without battery
    (or Battery-Only Supplement for buildings with a pre-existing solar array)
  2. Wiring diagram (see simplified Wiring Diagram and Site Plan samples showing information to include)
    1. CMLP requires production meter sockets for all solar projects, but not the production meter itself.  The installer must supply either a production meter (which will enable the customer to sell Class 1 RECs) or jumpers (meaning the customer will not be able to sell their Class 1 RECs) and a weatherproof cover in that socket.
    2. CMLP prefers 3-Line drawings (rather than 1-Lines) in all cases and requires them for projects that include batteries
  3. Specification sheets for all equipment
              (i.e. solar PV panels, inverters, and (if applicable) energy storage systems)
  4. CMLP Solar PV Rebate Application (see this document for how to calculate shade percentage)
  5. CMLP Solar PV Rebate Terms and Conditions
  6. Residential or Commercial Net Metering Policy Acknowledgement
              Note: per Light Board review, CMLP staff are modifying our policy on batteries and other options for solar arrays over 50 kW.
              We will update the NMA documents as soon as possible.
  7. Signed contract between installer and property owner

Note: Installer must contact Concord’s Building Department to file separate permits before work begins.  Electricians can visit the office in person or upload their documents (liability insurance certificate & license) and pay online via Permit Eyes.

C. Approval to Install from CMLP:

  1. CMLP Engineer conducts initial project review
  2. On-site visit:
    1. Solar-only projects: not usually needed
    2. Battery installations: Required pre-install walk-through with CMLP, Fire Dept, Building Dept, and installer
  3. CMLP sends signed APPROVAL to INSTALL document to property owner and installer.
    An email from CMLP with "Approval to Install" in the subject line marks successful completion of this step. On average, from the date CMLP receives the complete document set, it takes solar-only applications 1 month and solar + battery applications 2 months to get approved for install.

D. Install Equipment:

  1. Solar PV panels (and battery, if applicable) installed on property
  2. Installer or electrician (not homeowner) contacts Building Department for Electrical Inspector to visit site
    Call (978) 318-3235 from 7-9 am with permit number and desired inspection date and time.  Messages left after 9 am are returned the next morning.  Inspections can usually be completed within a week of the request.  CMLP is notified by the Building Department the day after permit approval.
  3. CMLP's Senior Utility Electrician, triggered by Building Department's approval email, does a final exterior site visit.  The owner does not need to be on the property at the time. The inspection covers: 
    1. System disconnects
    2. Equipment labels, warning placards, and map
    3. Any general safety concerns
    4. Verifies that a customer-owned meter or jumpers were installed by the solar company in the PV production meter socket

E. Approval to Operate from CMLP:

  1. CMLP Engineer conducts final project review
    Solar-only projects usually don't need an on-site visit
    Battery installations require in-person Witness Test for CMLP to confirm the wiring, equipment, disconnects, labels, battery charge / discharge settings, solar pass through, demand on local transformer following an extended power outage, simulated power outage, and verify time delay after power is restored.  The homeowner must be there to give access and the installer (or their electrician) must be there to operate the equipment.  Afterwards CMLP emails a signed Witness Test Letter for the installer to sign and return.
  2. CMLP emails signed APPROVAL to OPERATE document to property owner & installer
    An email from CMLP with "Approval to Operate" in the subject line marks successful completion of this step. On average, from the date CMLP issues the Approval to Install, it takes solar-only applications 2.5 months and solar + battery applications 4.5 months to get approved to operate.
  3. Property owner begins generating their own power!

F. Receive Your CMLP Solar PV Rebate:

Property owner receives one-time check by mail from Town of Concord for CMLP Solar PV Rebate (if rebate check requested rather than on-bill credit).  This arrives 6 – 8 weeks after Approval to Operate email.  Any rebate of $750 or less is issued as a credit on your electric bill.  If a customer requesting a check has been in arrears frequently in the past two years, CMLP may apply all or part of the rebate as a bill credit rather than as a check.  The rebate can also be directed to your solar installer to help you with cash flow.

If you have any questions, please contact:

Concord Municipal Light Plant
PO Box 1029
1175 Elm Street
Concord, MA 01742

ATTN: Pamela Cady
pcady@concordma.gov
(978) 318-3149