National Grid - Interconnection of Generators

Interconnection Process All Interconnection Service Applications Must Be Submitted Through Our Customer Application Portal.

Unsure how to use the portal? Watch this video for step-by-step instructions. Questions? Visit our help page.

The information contained or referred to herein is for reference purposes only, and shall not be relied upon for any purposes. The user of this webpage should independently verify all information before proceeding forward with any project.

To interconnect a distributed generation (DG) system, please review the following sections in order:

Note: Please use Chrome or Firefox browsers to online open or download the latest format documents such as .docx, .pptx, .xlsx etc.

The 2019 Residential Renewable Energy Growth program will have a cap of 12.23MW (The calendar year for the program is 4/1/2019-3/31/2020). The cap currently has 9.48MW available as of August 26, 2019. National Grid will accept applications until the conclusion of the program on 3/31/2020 or capacity restrictions are issued.

Effective June 1, 2018

All inverter-based solar PV projects 100 kW or less with applications submitted on or after June 1, 2018 are subject to ISO-NE Ride through Requirements. Changes will be required to your submitted documents Click this link for more information New Inverter Message.

Effective January 1, 2017
Notice for customers regarding Rhode Island Renewable Energy Growth (RE-Growth) dual meter installations

This notice serves to clarify the acceptable installation methodology for multiple meter installations related to Rhode Island's Renewable Energy Growth (RE-Growth) program. This notice does not nullify or supersede National Grid standard requirements for meter installation. It is provided for additional clarification, specifically related to the unique installations of Rhode Island RE-Growth.

The following installation approaches are acceptable. Any other installation approach is not acceptable by National Grid. All installations are subject to review and approval by National Grid. Clarification on the topic will be added to the next scheduled revision of ESB 756.

Note: Due to the required service change for this program if your electrical meter is currently located inside it will need to be moved outside at your location to meet National Grid standards.

Overhead Service Installations

At the home, provide single service from the weatherhead to a multi-gang meter socket, for installation of the multiple meters required for RE-Growth.
At the home, provide parallel services from the weatherhead to individual meter sockets, for installation of the multiple meters required for RE-Growth.

Note: Installation of a single service from the weatherhead to a junction box mounted on the side of the house, which would subsequently serve individual meter sockets is not acceptable. Bifurcation of the service for the purposes of serving multiple meters related to RE-Growth is only acceptable at the weatherhead.

Underground Service Installations

Provide single service to house, which will feed a multi-gang meter socket, for installation of the multiple meters required for RE-Growth. Expansion joint is required for the feeder entering the meter socket, which is consistent with National Grid standard practice for meter installation.

Note: Due to the nature of underground service installations, a multi-gang meter socket is the only acceptable means of installation.

Pre-Application Report Request
Application Process
Simplified Application with RE Growth enrollment option
Expedited Application
Standard Application
Simplified Network Application - information pending
Feasibility Study Process (for Renewable Process only)
Screening Process (for Expedited Process only)
Study Process (for Standard Process only) - information pending
Conditional Approval
Construction Process - information pending
Customer Construction - information pending
Witness Test Process (if applicable) - information pending
National Grid Construction (if applicable) - information pending
Project Completion Process
Completion Documentation
Net Meter Installation Process (if applicable)
Authorization to Interconnect
Post-Interconnection Information
First Bill Walk Through
Changes to System Ownership - information pending
Updating Billing Account Information - information pending
Customer Generator Modifications - information pending

Note about Time Frames: As per the Standards for Connecting Distributed Generation (RIPUC 2180) , Interconnecting Customers are required to respond promptly to any requests for signatures, information, documentation, and/or payments in compliance with the Time Frames described in the Interconnection Tariff. Failure to comply with these Time Frames during any stage of the interconnection process may result in an Interconnection Application being cancelled without compensation being provided to the Interconnecting Customer.

Note about Payments: In order to avoid issues while attempting to submit any payments (other than the initial application fee), Interconnecting Customers are advised not to submit any payments prior to receiving a corresponding invoice. Interconnecting Customers should follow the instructions provided on the invoice and any invoiced fees should only be submitted to the PO Box indicated on the invoice.

Pre-Application Report Request

Prior to submitting an Interconnection Application through either the Expedited or Standard Process (see Sections 3.2 of R.I.P.U.C. 2180 Standards for Connecting Distributed Generation), all Interconnecting Customers with Facilities that are 500 kW or greater must request and receive a Pre-Application Report from the Company. The Pre-Application Form is provided in Exhibit B. The Pre-Application Report is optional at the election of the Interconnecting Customer for those Facilities that are less than 500 kW. There is no fee for either a mandatory or optional Pre-Application Report.

To request a Pre-Application Report, please complete the following steps:

Standard Application Process

Prepare a Pre-Application Report Form (Exhibit B) in the online application portal in order to request a Pre-Application Report for the proposed location of the distributed generation system.

Attach a map or overhead picture from an online mapping website (e.g. Google Maps, Bing Maps) with the proposed location clearly marked, North indicated (if not at the top), and at least one cross street visible (if possible). A separate request should be submitted for each location that is being inquired about (One Exhibit B per location).

In response to your request, National Grid will provide a Pre-Application Report that describes the electrical service characteristics of the local Electric Power System (EPS) based on the information provided in the request form (Exhibit B).

Please refer to the Interconnection Documents webpage for a high level overview of the DG Interconnection Process and all relevant Interconnection Process documents.

Application Process

To install a distributed generation (DG) system, please complete the following steps in order prior to preparing an Interconnection Application (IA) for a customer:

Contractors (e.g. electricians, developers, and design engineers) should familiarize themselves with the most recent versions of the relevant interconnection standards:
1. RIPUC 2180 - Standards for Connecting Distributed Generation (also known as: "Interconnection Tariff")
2. ESB 756D - National Grid's technical requirements for DG interconnections
3. ESB 750 - National Grid's Specifications for Electrical Installations (relevant sections)

Note 1: Other guidance can be found on the Interconnection Documents page. All of the service documents for National Grid can be found on the Service Documents webpage.

Complete a Pre-Application Report by visiting the online application portal.. In Rhode Island, this step is optional for all DG systems; however, it is recommended for DG systems ≥500kW in aggregate AC generation capacity. Pre-Application Report requests must include:
The proposed location of the DG system (preferably including a street address and map view with multiple streets visible)
An existing electric billing account (if applicable)/p>
A description of the proposed generator(s)
If it is requested, National Grid will provide a Pre-Application Report that describes the electrical service characteristics of the local Electric Power System (EPS) based on the information provided in the request.
Prepare the customer's design diagrams for your proposed distributed generation system. Refer to the RI DG Design QuickGuide.

P.E.-stamped one-line diagram

Relay settings should appear on one-line (for non-simplified process systems this includes the settings internal to any inverters/generators and any external/redundant protection equipment)
Schematic drawings for all protection and control circuits, relay, current circuits, relay potential circuits, and alarm/monitoring circuits (if applicable)
Refer to the relevant standards (above) for applicable design criteria
Inverter/Generator equipment
AC Disconnect Switches
Meters (utility revenue meters & customer-owned production meters)
Service equipment/disconnects (all such equipment on the property)
Customer-owned transformers (if applicable)
Utility-owned transformers (including utility pole number, if applicable)
Technical Specification documents from the equipment manufacturers should be gathered for all major pieces of equipment, such as:
Inverter/Generator equipment (including internal relay settings)
Customer-owned transformers (if applicable)
Relays and Grounding Equipment (if applicable)

Note 2: Phone lines must be installed at the utility revenue meter for all generators that intend to export power (other than net metered customers ≤60kW in aggregate generation). Refer to the Phone Line and RTU Guidance for DG page for more information about phone line and RTU requirements

Note 3: A P.E.-stamped three-line diagram is required for any distributed generation system that includes generation equipment that is not UL-1741 certified. (It is also strongly recommended for any Standard Process applications and will likely be required later.)

By reviewing the documents listed above, particularly the Interconnection Tariff, contractors should be able to determine the application process(es) through which a DG system is eligible to be interconnected. However, below are some general recommendations for determining the most efficient process through which to interconnect. (Visit the appropriate application process section below to view the next step of the process.)

Simplified Process

Single-phase Listed inverter-based systems up to 15kW(AC) in aggregate generation capacity
Three-phase Listed inverter-based systems up to 25kW(AC) in aggregate generation capacity
Applicants in Providence and Pawtucket should refer to the Simplified Network Process guidance below.
Expedited Process
Listed inverter-based systems <500kW(AC) in aggregate generation capacity (that do not qualify for the Simplified Process)
Listed inverter-based systems <1,000kW(AC) in aggregate generation capacity with significant load behind the same meter
Standard Process
Listed inverter-based systems ≥500kW(AC) aggregate generation capacity without significant load behind the same meter
Listed inverter-based systems ≥1,000kW(AC) aggregate generation capacity
Any non-listed inverter-based systems of any aggregate generation capacity
Any non-inverter-based systems of any aggregate generation capacity
Simplified Network Process
Applicants (generally large-scale industrial facilities) should determine if their service is on a Spot Network.
Applicants in cities that have non-radial networks (i.e. Providence and Pawtucket), should refer to the Area Network Maps to determine whether or not the proposed project location is on an Area Network.
If a proposed project is located on a network and the aggregate generation capacity is less than 1/15th of the minimum load behind the same meter, then customer may apply to the Simplified Network Process. Otherwise, customers are advised to apply directly to the Standard Process.
If a proposed project is NOT located on a network, applicants should refer to the other guidance above to determine the most efficient process through which to interconnect.

Simplified Application Process

If you have not already visited it, please refer to the overall Application Process section before proceeding. (Download Simplified Interconnection Documents Zip Folder)

This application now includes the option to enroll in the Rhode Island Renewable Energy Growth Small Solar Program. Additional forms and requirements apply to be eligible for and receive a Certificate of Eligibility under this program. Please see the RE Growth page at www.ngrid.com/REGrowth for complete Solicitation and Enrollment Rules, Tax Policy Statement, and official tariffs.

In order to submit a successful Simplified Process Interconnection Application (IA) to interconnect a distributed generation (DG) system, please complete the following steps in order:

If the customer is in need of a new electrical service (e.g. there is no existing electric account at the proposed project location) or upgraded electrical service (e.g. proposing to install a three-phase DG system on a single-phase service), request it before proceeding! New customers are not required to send a copy of a recent electric bill, but they must provide a Work Request number and pending Account Number on the IA form. (Please contact customer service at 1-800-322-3223 to create the Work Request Number and to receive the Pending Account Number. More information can be found on the Apply for Service page.)

Note 1: Any upgraded service that is requested for an account with a pending IA will be put on hold until National Grid sends the Interconnecting Customer a Conditional Approval to Interconnect.

The Interconnecting Customer should review the Terms and Conditions for the Simplified Process (in Exhibit A of the Interconnection Tariff).
Prepare the Interconnecting Customer's IA materials (and have these materials initialed and signed by the appropriate parties).
Exhibit A Simplified Interconnection Application (IA) - Required for Net Metering
Exhibit A Simplified Interconnection Application (IA) - Required for RI-Re-Growth
Exhibit I - Retail Customer Agreement (if applicable) - Required for RI-Re-Growth and Net Metering
Legal Information Document - Required for RI-Re-Growth and Net Metering
Schedule B - Information Required for Net Metering Service form - Required for Net Metering
Recent copy of the retail customer's electric bill (for Existing Customers only)
Payment / Credit Transfer Form - Required for RI-Re-Growth
REC Assignment and Aggregation Form - Required for RI-RE-Growth
ACH Authorization Form - Required for RI-Re-Growth
W-9 (Customer must Retrieve from the IRS Website) - Required for RI-Re-Growth
Ownership and Segmentation Affidavit - Required for RI-Re-Growth

Note 2: In the Simplified Process, the Exhibit I must be submitted with the other IA materials in any instance where the owner and/or operator of the DG system is not the named responsible party on the host retail electric billing account (also known as the "Host Customer" or "Retail Customer").

Submit all of the Interconnecting Customer's IA materials and proposed design diagrams (refer to the Application Process section if necessary) within our online application portal.
One-Line Diagram - Required for RI-Re-Growth and Net Metering
Technical Specifications - Cut Sheets, Specs, and Technical References for all Equipment being used. (PDF files only) - Required for RI-Re-Growth and Net Metering
Exhibit A - Simplified Interconnection Application (IA) - Required for Net Metering
Exhibit A - Simplified Interconnection Application (IA) - Required for RI-Re-Growth
Exhibit I - Retail Customer Agreement (if Applicable) - Required for RI-Re-Growth and Net Metering
Legal Information Document - Required for RI-Re-Growth and Net Metering
Schedule B - Required for Net Metering
Recent copy of the retail customer's electric bill (for existing customers only) (for Existing Customers only)
Payment / Credit Transfer Form - Required for RI-Re-Growth
REC Assignment and Aggregation Form - Required for RI-RE-Growth
ACH Authorization Form - Required for RI-Re-Growth
W-9 (Customer must Retrieve from the IRS Website) - Required for RI-Re-Growth
Ownership and Segmentation Affidavit - Required for RI-RE-Growth
Once the IA materials are received at National Grid, a representative of National Grid's Distributed Generation Services (DGS) group will communicate with the contacts listed on the IA form and Legal Information Document about the status of the application and provide an application number.
Once all the initial documents (see above) are received and approved, the application is considered complete (application not project).
A representative of the DGS group will counter-sign and return the IA Form. (Visit the Project Completion Process section to view the next step of the process.)

Note 3: If minor System Modifications are required to interconnect the proposed DG system to the National Grid Electric Power System, the Interconnecting Customer should refer to the "Simplified Process" section of the Interconnection Tariff for more information.

Expedited Application Process

If you have not already visited it, please refer to the overall Application Process section before proceeding. (Download Expedited Interconnection Documents Zip Folder)

In order to submit a successful Expedited Process Interconnection Application (IA) to interconnect a distributed generation (DG) system, please complete the following steps in order:

If the customer is in need of a new electrical service (e.g. there is no existing electric account at the proposed project location) or upgraded electrical service (e.g. proposing to install a 200kW DG system behind an existing residential meter), request it before proceeding! New customers are not required to send a copy of a recent electric bill, but they must provide a Work Request number and pending Account Number on the IA form. (Please contact customer service at 1-800-322-3223 to create the Work Request Number and to receive the Pending Account Number. More information can be found on the Apply for Service page .)

Note 1: Any new or upgraded service that is requested for an account with a pending IA will be put on hold until the Interconnecting Customer signs an Interconnection Service Agreement.

Prepare the Interconnecting Customer's IA materials (and have these materials initialed and signed by the appropriate parties).
Exhibit C - Expedited/Standard Interconnection Application (IA) form - Required for RI-Re-Growth and Net Metering
Legal Information Document - Required for RI-Re-Growth and Net Metering
Schedule B - Required for RI-Re-Growth and Net Metering
Recent copy of the retail customer's electric bill (for Existing Customers only)
IA fee check made payable to National Grid
$3/kW - Max $2500 / Min $300
Scan a copy of the check before mailing it!

Note 2: In the Expedited Process, the Exhibit H should NOT be submitted with the other IA materials; it will be provided by National Grid as part of the Interconnection Service Agreement. However, contact information for the named responsible party on the host retail electric billing account (also known as the "Host Customer" or "Retail Customer") should be provided in the IA form and the Legal Information Document.

Submit all of the Interconnecting Customer's IA materials and proposed design diagrams (refer to the Application Process section if necessary).
Copy of any Pre-Application Reports related to the application provided by National Grid (if applicable)
P.E.-stamped One-Line Diagram (and Three-Line Diagram if applicable)
Technical Specifications (pdf files only)
Exhibit C (IA Form)
Legal Information Document
Schedule B

Once the IA fee check and signed IA form are received at National Grid, a representative of National Grid's Distributed Generation Services (DGS) group will communicate with the contacts listed on the IA form and Legal Information Document about the status of the application.
Once all the initial documents (see above) are received and approved, the application is considered complete (application not project).
Complete applications are forwarded to a Technical Support Consultant (in the Technical Sales & Engineering Support department - part of the DGS group) to perform a technical screening review. (Visit the Feasibility Study Process section or the Screening Process section to view the next step of the process.)

Standard Application Process

If you have not already visited it, please refer to the overall Application Process section before proceeding. (Download Standard Interconnection Documents Zip Folder)

In order to submit a successful Standard Process Interconnection Application (IA) to interconnect a distributed generation (DG) system, please complete the following steps in order:

If the customer is in need of a new electrical service (e.g. there is no existing electric account at the proposed project location) or upgraded electrical service (e.g. proposing to install a 500kW DG system behind an existing residential meter), request it before proceeding! New customers are not required to send a copy of a recent electric bill, but they must provide a Work Request number and pending Account Number on the IA form. (Please contact customer service at 1-800-322-3223 to create the Work Request Number and to receive the Pending Account Number. More information can be found on the Apply for Service page.)

Note 1: Any new or upgraded service that is requested for an account with a pending IA will be put on hold until the Interconnecting Customer signs an Interconnection Service Agreement.

Prepare the Interconnecting Customer's IA materials (and have these materials initialed and signed by the appropriate parties).
Exhibit C - Expedited/Standard Interconnection Application (IA) form - Required for RI-Re-Growth and Net Metering
Legal Information Document - Required for RI-Re-Growth and Net Metering
Schedule B - Required for Net Mertering.
IA fee check made payable to National Grid
Non-Renewable: $3 per kW(AC) - Minimum $300 / Maximum: $2,500
Renewable: refer to table in tariff to determine your feasibility study fee
Scan a copy of the check before mailing it!

Note 2: In order to request the Feasibility Study (as opposed to the Any DG Process), ensure that the "Yes" option is checked on the IA form

Note 3: In the Standard Process, the Exhibit H should NOT be submitted with the other IA materials; it will be provided by National Grid as part of the Interconnection Service Agreement. However, contact information for the named responsible party on the host retail electric billing account (also known as the "Host Customer" or "Retail Customer") should be provided in the IA form and the Legal Information Document.

Submit all of the Interconnecting Customer's IA materials and proposed design diagrams (refer to the Application Process section necessary).

Complete the following materials on our online application portal.
i. Copy of any Pre-Application Reports related to the application provided by National Grid - Required for RI-Re-Growth and Net Metering
ii. P.E.-stamped One-Line Diagram and Three-Line Diagram - Required for RI-Re-Growth and Net Metering
iii. Technical Specifications (pdf files only) - Required for RI-Re-Growth and Net Metering
iv. Exhibit C (IA Form) - with Standard Process requested! - Required for RI-Re-Growth and Net Metering
v. Legal Information Document - Required for RI-Re-Growth and Net Metering
vi. Schedule B - Required for Net Mertering
Once the IA fee check and signed IA form are received at National Grid, a representative of National Grid's Distributed Generation Services (DGS) group will communicate with the contacts listed on the IA form and Legal Information Document about the status of the application.
Once all the initial documents (see above) are received and approved, the application is considered complete (application not project).
Complete applications are forwarded to a Technical Support Consultant (in the Technical Sales & Engineering Support department - part of the DGS group) to perform an initial technical review. (Renewable DG applications will undergo a Feasibility Study instead of an initial review. Visit the Feasibility Study Process section to view the next step in the process.)
Once the initial technical review is completed, National Grid will offer the Interconnecting Customer an executable Exhibit E - Impact Study Agreement, including a cost estimate and anticipated timeline for the Impact Study. receipt of a signed Exhibit E, National Grid will prepare and issue an invoice (as per the payment terms offered in the Exhibit E and as indicated on the Legal Information Document).
The Interconnecting Customer pays the invoiced cost in full.
The Interconnecting Customer may be required to provide additional information, documentation, and/or corrections (as identified during the initial technical review) before proceeding.
Upon receipt of the full payment (and all necessary revised documentation), National Grid will initiate the Impact Study. (Visit the Study Process section to view the next step of the process.)

Simplified Network Application Process

Information Pending

Feasibility Study Process(for Renewable DG Applications only)

If you have not already visited it, please refer to the Standard Application section before proceeding.

In the Standard Process for Renewable Distributed Generation (DG), once the Interconnecting Customer has been notified that its DG Interconnection Application (IA) has been deemed complete (i.e. all application materials are accounted for), National Grid shall direct the Interconnecting Customer (and its representatives) through the following process:

A National Grid Technical Support Consultant (in the Technical Sales & Engineering Support department - part of the Distributed Generation Services (DGS) group) will conduct a feasibility study. This feasibility study generally includes:
A review of the local and area National Grid Electric Power System (EPS)
A review of the proposed DG design diagrams and other IA materials
An identification of any missing or deficient customer documentation or EPS information
An identification of obvious regulatory or code infractions based on a comparison of the proposed DG design diagrams and the National Grid EPS
Answers to screening questions (as per "Figure 1 - Schematic of Rhode Island DG Interconnection Process" and the accompanying notes provided in the Interconnection Tariff)
Once the Technical Support Consultant has completed its feasibility, National Grid will provide the Interconnecting Customer with a Feasibility Study Report, which will:
Provide a cost estimate of the potential construction costs.
Refer customers to impact study fees in the table of the tariff.
If the Interconnecting Customer requests an Impact Study, National Grid will provide an Exhibit E - Impact Study Agreement. Then:
The Interconnecting Customer signs and returns the Exhibit E.
Upon the receipt of a signed Exhibit E, National Grid will prepare and issue an invoice (as per the payment terms offered in the Exhibit E and as indicated on the Legal Information Document).
The Interconnecting Customer pays the invoiced cost in full.
The Interconnecting Customer may be required to provide additional information, documentation, and/or corrections (as identified in the Feasibility Study Report) before proceeding.
Upon receipt of the payment (and all necessary revised documentation), National Grid will initiate the Impact Study. (Visit the Study Process section to view the next step of the process.)

Screening Process(for Expedited Applications only)

If you have not already visited it, please refer to the Expedited Application section before proceeding.

In the Expedited Process, once the Interconnecting Customer has been notified that its distributed generation (DG) Interconnection Application (IA) has been deemed complete (i.e. all application materials are accounted for), National Grid shall direct the Interconnecting Customer (and its representatives) through the following process:

A National Grid Technical Support Consultant (in the Technical Sales & Engineering Support department - part of the Distributed Generation Services (DGS) group) will conduct an initial technical review screening. This initial technical review screening generally includes:
A review of the local and area National Grid Electric Power System (EPS)
A review of the proposed DG design diagrams and other IA materials
An identification of any missing or deficient customer documentation or EPS information
An identification of obvious regulatory or code infractions based on a comparison of the proposed DG design diagrams and the National Grid EPS
Answers to screening questions (as per "Figure 1 - Schematic of Rhode Island DG Interconnection Process" and the accompanying notes provided in the Interconnection Tariff)
Once the Technical Support Consultant has completed its initial technical review screening, National Grid will provide the Interconnecting Customer with a Screening Memo.
If the proposed DG design diagrams result in the IA passing all of the screening questions, National Grid will offer a Conditional Approval to the Interconnecting Customer along with the Screening Memo. (Visit the Conditional Approval section to view the next step of the process.)
If the proposed DG design diagrams result in the IA failing the screening questions, National Grid will offer the Interconnecting Customer an Exhibit C - Supplemental Review Agreement along with the Screening Memo.

Note 1: In some cases, where extremely minor National Grid EPS system modifications are required (and the IA would otherwise pass the screening questions), National Grid may opt to waive its right to require a Supplemental Review. In such instances, Interconnecting Customers will be provided additional guidance in the Screening Memo about how to proceed.

In the case where National Grid provides an Exhibit C - Supplemental Review Agreement, if the Interconnecting Customer wishes to proceed with the Supplemental Review:
The Interconnecting Customer signs and returns the Exhibit C.
Upon the receipt of a signed Exhibit C, National Grid will prepare and issue an invoice (as indicated on the Legal Information Document).
The Interconnecting Customer pays the invoiced cost in full.
The Interconnecting Customer may be required to provide additional information, documentation, and/or corrections (as identified in the Screening Memo) before proceeding.
Upon receipt of the full payment (and all necessary revised documentation), National Grid will initiate the Supplemental Review.
Once the Supplemental Review is initiated, a Technical Support Consultant will coordinate with an Interconnection Engineer (in the Retail Connections Engineering department - part of the DGS group) and any other necessary engineering resources to conduct the Supplemental Review. The Supplemental Review generally includes:
A quick review of the information provided in the Screening Memo
Answers to the Supplemental Review Screens (as per "Figure 1 - Schematic of Rhode Island DG Interconnection Process" and the accompanying notes provided in Interconnection Tariff)
An identification of possible design diagram changes that may allow the IA to pass the Supplemental Review Screens (if applicable)
Once the Interconnection Engineer has completed the Supplemental Review, National Grid will provide the Interconnecting Customer with a Supplemental Review Memo.
If the proposed DG design diagrams result in the IA passing all of the Supplemental Review Screens, National Grid will offer a Conditional Approval to the Interconnecting Customer along with the Supplemental Review Memo. (Visit the Conditional Approval section to view the next step of the process.)
If the proposed DG design diagrams result in the IA failing the Supplemental Review Screens, National Grid will offer the Interconnecting Customer:
Options to address the failed Supplemental Review Screens (if applicable, refer to guidance in the Supplemental Review Memo)
An executable Exhibit E - Impact Study Agreement, including a cost estimate and anticipated timeline for the Impact Study
In the case where National Grid provides an Exhibit E - Impact Study Agreement, if the Interconnecting Customer wishes to proceed with the Impact Study:
The Interconnecting Customer signs and returns the Exhibit E.
Upon the receipt of a signed Exhibit E, National Grid will prepare and issue an invoice (as per the payment terms offered in the Exhibit E and as indicated on the Legal Information Document).
The Interconnecting Customer pays the invoiced cost in full.
The Interconnecting Customer may be required to provide additional information, documentation, and/or corrections (as identified in the Supplemental Review Memo) before proceeding.
Upon receipt of the payment (and all necessary revised documentation), National Grid will initiate the Impact Study. (Visit the Study Process section to view the next step of the process.)

Note 2: In the event that the Interconnecting Customer signs and returns an Exhibit E, the interconnection application will be transferred from the Expedited Process to the Standard Process. For the remainder of the application process, the interconnection application will be considered a Standard Process application.

Study Process(for Standard Applications only)

Information Pending

Conditional Approval

If you are looking for information about preparing a new application, please refer to the overall Application Process section before proceeding.

The information on this section only applies to distributed generation (DG) Interconnection Applications (IA) considered under the Expedited Process or the Standard Process. For information on other IA's please refer to the Simplified Application section.

Once all required reviews and studies for an IA are complete, National Grid's Distributed Generation Services (DGS) group will draft an executable Interconnection Service Agreement (ISA) based on the results of the required reviews and studies. As per the Interconnection Tariff, the ISA will generally include:
A description of the customer's proposed DG system and National Grid's Electric Power System (EPS)
Any special operating requirements for the customer
A description of required EPS System Modifications (e.g. upgrades to the existing electric service)
An estimated cost & estimated timeline for National Grid construction (if applicable)

Note 1: The information and requirements provided in the Interconnection Service Agreement (ISA) will vary depending on the level of review or study that was required by the Interconnection Tariff, the configuration of the customer's proposal, and the existing National Grid Electric Power System (EPS).

The Conditional Approval email will include the following:
The most recent technical findings document (e.g. screening memo)
The executable ISA, which includes:
Exhibit G - Interconnection Service Agreement (including any attachments)
Exhibit H - Retail Customer Agreement (if applicable)
A checklist of pending Completion Documentation

Note 2: The Exhibit H must be submitted in any instance where the owner and/or operator of the DG system is not the named responsible party on the host retail electric billing account (also known as the "Host Customer" or "Retail Customer").

Once National Grid issues the Conditional Approval, the Interconnecting Customer must respond in a timely manner (as per applicable time frames in the Interconnection Tariff).
If the Interconnecting Customer does not agree with the terms, conditions, and attachments of the executable Interconnection Service Agreement (or the results in the technical findings document), please refer to the appropriate process section in the Interconnection Tariff.
If the Interconnecting Customer agrees with the terms, conditions, and attachments of the executable Interconnection Service Agreement, the Interconnecting Customer must promptly return the signed, dated, and initialed Interconnection Service Agreement (including the Exhibit H, if applicable).
Once National Grid receives the signed ISA, National Grid will:
Issue an invoice for the EPS System Modification costs based on the payment terms of the ISA and the Interconnection Tariff (if applicable)
Execute the ISA and return it to the Interconnecting Customer.
Proceed with its obligations to interconnect the Interconnecting Customer's DG system based on the terms and conditions of the ISA and the Interconnection Tariff.
Once the Interconnecting Customer submits the signed ISA, it should proceed with the construction of it's DG system and work to meet its other obligations based on the terms and conditions of the ISA and the Interconnection Tariff. (Visit the Construction Process section to view the next step of the process.)

Construction Process

Information Pending

Customer Construction

Information Pending

Witness Test Process

Information Pending

National Grid Construction

Information Pending

Project Completion Process

The information on this section only applies to distributed generation (DG) Interconnection Applications (IA) that have already received a counter-signed IA form under the Simplified Process or that have already received a Conditional Approval under the Expedited or Standard Processes.

If you have not already visited it, please refer to the Construction Process section before proceeding. (In particular, Standard Process applicants should refer specifically to the Witness Test Process section before proceeding.)

Once the Interconnecting Customer's DG system has been constructed and installed, it is the responsibility of the Interconnecting Customer or one of its representatives (e.g. the installer) to submit the appropriate project completion documentation for review by National Grid prior to energizing the system (other than for testing purposes). Please refer to the Completion Documentation section for more information.
Additionally, Interconnecting Customers that have applied for Net Metering must wait for their traditional, detented utility revenue meter to be replaced with a new bi-directional net meter. Attempting to operate a DG system behind a traditional meter may result in billing issues! Please refer to the Net Meter Installation Process section for more information.

Note 1: Qualifying Facilities may also need to have a new meter installed to properly register their generation. Please also refer to the links above for more information.

Once the Interconnecting Customer has completed all of the relevant process steps and fulfilled all of the requirements specific to its Interconnection Application, National Grid will issue an Authorization to Interconnect. Interconnecting Customers are NOT permitted to operate any generation capacity prior to receiving an official Authorization to Interconnect and will be held liable for any damages that may occur as a result of unauthorized operation. (Visit the Authorization to Interconnect section to view the next step in the process.)

Completion Documentation

If you have not already visited it, please refer to the Project Completion Process section before proceeding.

Every Interconnecting Customer will be required to submit a Certificate of Completion, which should be filled out during the municipal electric inspection:
Exhibit A2 - Certificate of Completion (Simplified only) - Required for RI-Re-Growth and Net Metering
Exhibit B2 - Certificate of Completion (Expedited or Standard) - Required for RI-Re-Growth
In addition to the Certificate of Completion, Interconnecting Customers shall generally be required to submit the completion documentation (as described in the checklists provided below) after constructing and installing a DG system (but prior to receiving an Authorization to Interconnect from National Grid).
Simplified Process Checklist
Expedited Process Checklist
Standard Process Checklist
RI-RE-Growth Process Checklist

Note 1: The checklists provided above are only general checklists. Additional pieces of documentation may be required depending on the specific circumstances related to an Interconnecting Customer's IA. Any specific requirements for completion documentation will be identified or referenced in the Interconnection Service Agreement and/or the Conditional Approval email.

Once all of the required completion documentation has been submitted, reviewed, and approved by National Grid, a representative of the Distributed Generation Services (DGS) group will notify the Interconnecting Customer. (Visit the Project Completion Process section to view information about the remainder of the interconnection process.)

Net Meter Installation Process

If you have not already visited it, please refer to the Project Completion Process section before proceeding.

For any DG systems that are capable of exporting power (other than net metered customers <=60 kW in aggregate generation), a dedicated phone line must be installed at the meter. Refer to the Phone Line and RTU Guidance for DG page for more information about phone line and RTU requirements. In any instance where a phone line is required, the Interconnecting Customer must provide the phone number to National Grid.
Once the Interconnecting Customer has completed all of the relevant process steps and fulfilled all of the requirements specific to its IA, National Grid's Distributed Generation Services (DGS) group will request that a new net meter be installed. As part of this request, the DGS group will forward information along to the meter services and account services representatives in order to process the request, including:
Account information (including the Schedule B)
Contact information
Phone number for the dedicated phone line (if applicable)
An estimated in-service date

Note 1: For accounts metered via a programmable meter (i.e. meters tied into a CT cabinet or at a service transformer), the preparation work required to install a net meter can be substantial and may require several weeks of lead-time. In such cases, it is strongly recommended that the Interconnecting Customer (or one of its representatives) regularly communicate with the DGS group regarding any changes to the estimated in-service date prior to submitting the project completion documentation.

Once the request for the new meter installation has been submitted, the meter installation is typically scheduled and completed within 15 business days.
Once the new meter has been installed by National Grid, a representative of the DGS group will notify the Interconnecting Customer. (Visit the Project Completion Process section to view information about the remainder of the interconnection process.)

Authorization to Interconnect

The information on this section only applies to distributed generation (DG) Interconnection Applications (IA) that have already completed all of the applicable, preceding steps in the interconnection process. If you are looking for information about preparing a new application, please refer to the overall Application Process section.

If you have not already visited it, please refer to the Project Completion Process section before proceeding.

Once the Interconnecting Customer has completed all of the relevant process steps and fulfilled all of the requirements specific to its Interconnection Application, National Grid will issue an Authorization to Interconnect. Interconnecting Customers are NOT permitted to operate any generation capacity prior to receiving an official Authorization to Interconnect and will be held liable for any damages that may occur as a result of unauthorized operation.
Upon receiving the Authorization to Interconnect the Interconnecting Customer may energize its DG system (subject to the terms and conditions of the Interconnection Tariff and any agreements between National Grid and the Interconnecting Customer).

Note about net metering credits: The net metering credits may not be applied to the host account (where the net meter is located) until the following billing cycle. If your system is transferring net metering credits to other accounts, the non-host account(s) may need to wait for an additional billing cycle (beyond the delay for the host account) before the net metering credits are applied to the non-host account(s).

It is required that the Interconnecting Customer safely operates and maintains it's DG system in accordance with all applicable laws, rules, and regulations governing distributed generation. In particular, the Interconnecting Customer should schedule regular maintenance and must maintain any permanent plaques and other signage related to its DG system.
Additionally, the Interconnecting Customer is required to notify National Grid of any changes (or proposed changes) related to: the configuration or operation of its generating equipment, the ownership of the DG system, or the host retail electric billing account. (Visit the Post-Interconnection Information section to view post-interconnection information.)
In general, after the Interconnecting Customer receives the Authorization to Interconnect, customers should review this website periodically for changes and updates. Also, any questions that may arise should be directed to National Grid's customer service representatives via phone at (800) 322-3223.

Note: In the event of an emergency, contact the local emergency services (dial 911).

Post-Interconnection Information

First Bill Walk Through

Please review our First Bill Walk Through presentation as a guide to understand your net metering bill.

Changes to System Ownership

Information Pending

Updating Billing Account Information

Information Pending

Customer Generator Modifications

Note about Time Frames: As per the Standards for Connecting Distributed Generation (RIPUC 2180), Interconnecting Customers are required to respond promptly to any requests for signatures, information, documentation, and/or payments in compliance with the Time Frames described in the Interconnection Tariff. Failure to comply with these Time Frames during any stage of the interconnection process may result in an Interconnection Application being cancelled without compensation being provided to the Interconnecting Customer.

Please refer to the Interconnection Documents webpage for a list of all relevant interconnection process documents.

Please refer to the Net Metering webpage for more information about billing options related to DG interconnections.

Contact E-mail: distributed.generation@nationalgrid.com

DISCLAIMER: All content and information provided on this 'process' webpage, including links to other National Grid webpages or documents and all of the content and information provided therein, is solely to provide customers, contractors, and other parties with additional useful guidance regarding National Grid's typical distributed generation interconnection process and matters related thereto. In all instances, the content and information provided by National Grid is superseded by the applicable laws, rules, regulations, tariffs, and regulatory decisions governing the distributed generation interconnection process and all matters related thereto in the relevant jurisdictions, all as may be amended from time to time. The content and information contained herein is not intended to be all inclusive of every process or action available to users with respect to the interconnection of distributed generation. It is the sole responsibility of users of this website to independently verify the process to interconnect its distributed generation, as well as the status of any changes, pending changes, or updates to the process described herein. National Grid shall not be held liable under any circumstances for any errors, omissions, inaccurate, and/or out-dated content or information provided herein.