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Investor-owned utility

National Grid (Nantucket Electric) interconnection application

National Grid (Nantucket Electric) is an investor-owned utility serving 12,966 residential customers in Massachusetts (EIA-861, 2025). Applications: Own online portal (National Grid Customer Application Portal (Salesforce)). Gridpol files National Grid (Nantucket Electric) interconnection applications for licensed installers – solar, storage and EV chargers – with single-line diagram and site plan, unlimited for $500 a month.

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Partly researched from official sources. verify on first project: assumed same National Grid MA portal/tariff as Massachusetts Electric (Nantucket Electric is a National Grid MA affiliate); confirm Nantucket-specific tariff and any island grid limits.

National Grid (Nantucket Electric) at a glance

Utility

Nantucket Electric Co (National Grid plc)

Type

Investor-owned utility

EIA utility ID

13206

Residential customers

12,966 (EIA-861, 2025)

Net-metered residential customers

312 (EIA-861, 2025)

Service territory

1 county in Massachusetts

How to apply

Own online portal – National Grid Customer Application Portal (Salesforce) · official link

Who submits

Installer/developer submits in portal on behalf of Interconnecting Customer (system owner); Exhibit H required if billing account holder is not system owner; registered users communicate via case chatter.

Export compensation

NEM – Net Metering Provision M.D.P.U. 1625 (03/01/2026) / SMART
Schedule Z required

Review time (official)

DPU-approved interconnection tariff (Simplified, radial): acknowledge 3 BD, completeness 10 BD, screens 15 BD (20 BD if Screen 5 fails), total max 25 BD (30 BD); witness test within 10 BD of Certificate of Completion; Authorization to Interconnect within 5 BD after requirements and meter installation.

Documents National Grid (Nantucket Electric) asks for

  • Interconnection application formExhibit A Simplified Interconnection Application (M.D.P.U. 1646, 11/1/2026), webform with e-signature, signature & date required Gridpol prepares this.
  • Site plan / site layoutTo scale with scale bar, north arrow, property lines, streets, all meters, isolation device, PCC, nearest pole number, existing systems (ESB 756 C 5.1.4) Gridpol prepares this.
  • Single-line diagram (one-line)Line diagram; equipment must match application and Equipment Selector; required notes on grouped/lockable metering and disconnects; ESS charge/discharge and derating notes Gridpol prepares this.
  • PV module spec sheetTechnical specification sheets for all equipment
  • Inverter spec sheetPlus UL 1741 SB certificate
  • Battery spec sheet (when applicable)ESS Questionnaire (webform) + cut sheets; total ESS kWh and AC/DC coupling must match
  • Net metering / net billing agreement (when applicable)Schedule Z (M.D.P.U. 1646) for net metering
  • Other utility-specific document (when applicable)Exhibit H Retail Customer Agreement if billing account holder is not system owner; Exhibit I Landowner Consent; curtailment/derating letter on manufacturer letterhead if system larger than export
  • Final inspection sign-offExhibit A2 Certificate of Completion + Simplified Process Completion Documentation Checklist + commissioning memo
  • Photos (meter, main panel, equipment) (when applicable)PV plaques must be visible in pictures accompanying completion documentation

How the National Grid (Nantucket Electric) process runs

  1. (If new/upgraded service needed, request it first.) Installer submits Simplified Process application (Exhibit A) with supporting documents through the utility portal.
  2. Utility acknowledges receipt within 3 business days; completeness determination within 10 business days.
  3. Utility completes screens within 15 business days (20 if Screen 5 fails); total max 25 business days (30 with Screen 5 failure).
  4. Utility countersigns application approval line = Conditional Approval to Interconnect (minor system modifications billed if needed).
  5. Install facility; local electrical wiring inspector signs Certificate of Completion (installing electrical contractor also completes it).
  6. Return Certificate of Completion (and completion documentation); utility may perform Witness Test within 10 business days or it is deemed waived.
  7. Meter installation; utility issues Authorization to Interconnect within 5 business days after requirements met and meter installed. No parallel operation before Authorization to Interconnect.

Fees

FeeApplies toNote
$28Simplified application feeAs listed on NG MA documents page (DPU 15-155)
$4.50/kW (min $300, max $7,500)Expedited/Standardper tariff

Utility fees are paid by the installer or customer; they are not part of the Gridpol plan.

Size levels and limits

LevelUp toNote
Simplified50 kW<=50 kW AC system size with <=25 kW AC total export (NG checklist 08/2026, MDPU 1632/1646)
ExpeditedNot Simplified; Standard recommended for non-inverter and >=500 kW

Storage, EV and stamps

Battery storage

Batteries (ESS) must be entered in portal, ESS Questionnaire required (DPU 19-55 interim guidance); AC/DC coupling, kWh and charge/discharge intentions must be shown on one-line and match all documents; curtailment letter if export limited.

EV chargers

Service work for EV: 'New EV - Electric Service Form' and 'Electric Service Upgrade Form' (PDF, 8/15/2024) on NG MA documents page; requires pending/active billing account.

PE stamp

NG checklist: Electrical PE stamp required for any non-PV-only project (e.g., PV+storage) in Simplified, and for all Expedited; site plans stamped by Electrical PE in project state per ESB 756 C 5.1.4(A). – PE-stamped drawings are not included in Gridpol.

Common issues the utility lists

  • Equipment on line diagram not matching application/Equipment Selector/completion documentation
  • Missing ESS Questionnaire or ESS data mismatch (kWh, AC/DC coupling, aggregate size)
  • Address mismatch between portal, site plan and application
  • Missing required one-line notes (grouped, outside, 24/7 lockable metering and disconnects)
  • PV plaques not visible in completion photos

Gridpol’s pre-submission check covers these before we file.

Sources

Massachusetts interconnection rule

Commission

Massachusetts Department of Public Utilities (DPU)

Interconnection rule

DPU-approved uniform 'Standards for Interconnection of Distributed Generation' tariff of each distribution company (National Grid M.D.P.U. No. 1468; Eversource/NSTAR M.D.P.U. No. 55D; Unitil/FG&E M.D.P.U. No. 484); dockets incl. D.P.U. 19-55, D.P.U. 23-140 – Standards for Interconnection of Distributed Generation · source

Applies to

The investor-owned electric distribution companies (Eversource/NSTAR Electric, National Grid/Massachusetts Electric & Nantucket Electric, Unitil/Fitchburg Gas & Electric). Municipal light plants are not subject.

Application form

Uniform tariff exhibits: Exhibit A Simplified Process Interconnection Application (with Certificate of Completion attachment), Exhibit B Pre-Application Report form, Exhibit C Expedited/Standard application; Interconnection Service Agreement.

Timelines

All time frames in Company Business Days. Simplified (radial): acknowledgement 3 BD, completeness 10 BD, screen review (20 BD if failing screen 5), conditional approval by signed application, witness test within 10 BD of Certificate of Completion or deemed waived, Authorization to Interconnect within 5 BD. Pre-Application Report required >= 250 kW, issued within 10 BD (fee $100 <250 kW, $250 250-500 kW, $750 >500 kW).

Fees

Simplified $28; Expedited/Standard $4.50/kW (min $300, max $7,500) plus supplemental review/studies at cost; witness test actual cost up to $300 plus driving time (Table 6).

Insurance

No insurance required for facilities eligible for Class I net metering (<= 60 kW) per 220 CMR 18.03(2) (company recommends adequate insurance). Otherwise general liability: $500,000 for >10-100 kW; $1M for >100 kW-1 MW; $2M/$5M aggregate for >1-5 MW; $5M for >5 MW (tariff Sec. 11.1).

External disconnect

For Listed inverters the Company MAY require an external disconnect switch (or comparable device by mutual agreement) at the PCC, accessible at all times, gang-operated, visible break, lockable open (tariff 4.2.3.1(b)).

Export compensation

NEM – M.G.L. c. 164 §§ 138-140; 220 CMR 18.00 (Net Metering)
220 CMR 18.02: Class I <= 60 kW (any eligible generation); Class II > 60 kW to <= 1 MW and Class III > 1 MW to <= 2 MW (agricultural, anaerobic digestion, solar or wind). Subject to aggregate net metering caps (not re-read). Applies to distribution companies only.

Not bound by the rule

Municipal light plants (about 40, e.g., WGELD) are not subject to the DPU interconnection tariff or 220 CMR 18.00 and set their own interconnection and net metering policies (some use a similar simplified application).

Other utilities in Massachusetts

All Massachusetts utilities →

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$500 / month

Unlimited interconnection applications. 12-month agreement, signed online. The agreement starts the day you sign; first invoice right away, then monthly.

  • Unlimited interconnection applications
  • Single-line diagram and site plan for every application
  • Pre-submission check against the utility’s requirements
  • Homeowner e-signature link for the authorization
  • Filing in your utility portal accounts or by the utility’s method
  • Utility questions, corrections and resubmissions
  • Follow-up through approval, inspection and PTO
  • Customer list, exports, API and webhooks
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Applications are typically submitted within 2 business days after complete documents. Utility review times are set by each utility.

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