A developer in central Massachusetts brought us a 1.4 MW ground-mount plan set this month with no battery on it. The SMART application was next. That order of work is backward under SMART 3.0. Above 1 MW, the SMART 3.0 energy storage requirement applies unless the project qualifies for an exemption. If it applies, the battery is not an add-on. It is on the site plan, the one-line, the fire review, and the interconnection application from the first revision.
DOER filed final revised SMART 3.0 regulations under 225 CMR 28.00 with the Secretary of State on September 11, 2026. Check the current text before you rely on any summary, including this one. What follows is how the storage rule has been described in DOER's program materials and guideline.
What the SMART 3.0 energy storage requirement says
DOER's guideline ties the requirement to 225 CMR 28.07(4)(e). A solar tariff generation unit above the threshold has to be co-located with an energy storage system that meets the eligibility rules in 225 CMR 28.07(5)(e)1. DOER's overview says SMART 3.0 raised the size that triggers the requirement from 500 kW to 1 MW.
There are two ways out:
- Location-based adder. The storage requirement does not apply to a generation unit that receives a location-based adder.
- Good-cause exception. A project can ask DOER for a good-cause exception to the storage requirement.
Separately, small projects of 25 kW or less no longer receive a storage adder under SMART 3.0. That matters for residential proposals, not for this plan set.
Our posts on the SMART 3.0 Statement of Qualification and final Statements of Qualification cover the application side. Decide the adder question before the drawings, because it decides whether there is a battery to draw.
The battery belongs on every sheet
Once storage is in, a 1 MW plan set changes in five places.
- Site plan. The battery enclosure or container, its pad, separation distances to the array, buildings, and property lines, and fire apparatus access, all dimensioned.
- One-line. The battery as its own source, its inverter or power conversion system, its ratings, and how it ties into the AC collection system.
- Operating mode. Whether the battery charges only from the array or also from the grid, and any export limit. Write it on the one-line and in the general notes.
- Fire and life safety. Energy storage requirements under the fire code edition Massachusetts enforces, with the listing and the hazard mitigation the fire department will ask about.
- Equipment schedule. Model, quantity, energy rating in kWh or MWh, and power rating in kW or MW.
Athol Energy prepares commercial and utility plan sets for solar and solar-plus-storage projects in Massachusetts. We are not the battery vendor or the fire protection engineer of record. We put the battery on the drawings so every reviewer is reading the same system.
Storage changes the interconnection and the local permit
A battery changes what the utility studies. Charging from the grid is load. Discharging is generation. The application has to say which the project will do and when. If the project is in an area with a planned grid upgrade, our post on Massachusetts capital investment projects explains why the exact AC size and storage description matter for cost sharing.
On the town side, a storage facility under 100 MWh is in the local consolidated permitting path, together with a solar facility under 25 MW. Our post on the Massachusetts consolidated local permit covers the 12-month clock. A battery added after the local application is complete is a change to a filed application. Add it before.
Keep the numbers the same everywhere
The commercial utility solar plan set post covers how sets break when different people edit different sheets. Storage adds two more numbers to keep consistent: energy and power. Put the solar AC size, the storage power rating, and the storage energy rating in the revision block. If any of the three changes, every sheet that states them changes in the same revision.
Questions about storage under SMART 3.0
What size project triggers the SMART 3.0 storage requirement?
DOER's materials describe the trigger as projects above 1 MW, raised from 500 kW under the earlier program. Check the September 2026 final regulations for the current text.
Are any projects exempt?
Yes. The requirement does not apply to a generation unit that receives a location-based adder, and a project can request a good-cause exception from DOER.
Does adding storage change the interconnection application?
Yes. The application has to describe the storage system, its ratings, and whether it charges from the grid or only from the array, because that changes what the utility studies.
If a Massachusetts ground-mount over 1 MW is still drawn without a battery, settle the adder question this week. Massachusetts solar design from Athol Energy will put the storage system on every sheet. Contact us.