Log in links for this page

Mayflower Wind SouthCoast

EFSB 22-04/D.P.U. 22-67/22-68: Mayflower Wind petitions for approval to construct 2.7 miles of high voltage export cables offshore in Massachusetts state waters, making landfall at Brayton Point, and continuing onshore at Brayton Point in the Town of Somerset, Massachusetts along with a new high voltage converter substation, and 0.2 miles of high voltage underground transmission lines onshore in the Town of Somerset, Massachusetts.

Table of Contents

Public Comment Hearing

The Siting Board conducted a remote public comment hearing regarding the Project on October 11, 2022.  A copy of the full public comment hearing notice can be accessed at: https://fileservice.eea.comacloud.net/FileService.Api/file/FileRoom/15454376.

A recording of the public comment hearing was posted to the Department’s YouTube channel, at https://www.youtube.com/watch?v=cbbspUD8f_s.  The transcript of the public comment hearing was posted to the DPU Fileroom at https://fileservice.eea.comacloud.net/FileService.Api/file/FileRoom/15661351.

 Written Comments

The Siting Board will also accept written comments on the Project.  Written comments will be most useful to the Siting Board if submitted by Tuesday, October 25, 2022

Participation in Proceedings

Persons or groups who wish to be involved in the Siting Board proceeding, beyond providing comments at the public comment hearing or in writing, may seek either to intervene as a party or to participate as a limited participant.  A petition to intervene or participate must be filed with the Siting Board in electronic format, by email or email attachment, to dpu.efiling@mass.gov. and to Robert.J.Shea@mass.gov no later than the close of business (5:00 p.m.) on Tuesday, October 25, 2022. For those individuals and groups that are “substantially and specifically” affected by energy proposals, and wish to participate actively in the proceeding, please visit the link below to learn more.

File a petition to intervene in an EFSB or DPU Siting case | Mass.gov

Project Information

Mayflower Initial Petition and Application

Mayflower Wind’s three petitions have been consolidated for hearing before the Siting Board under docket number EFSB 22-04/D.P.U. 22-67/22-68.  Under G.L. c. 164, § 69J, the Siting Board will review Mayflower Wind’s filing to determine whether the Project would provide a reliable energy supply for the Commonwealth, with a minimum impact on the environment, at the lowest possible cost.  Under G.L. c. 164 § 72, the Siting Board will determine whether the proposed Project is necessary, serves the public convenience, and is consistent with the public interest.  Under G.L. c. 40A, § 3, the Siting Board will determine whether the requested zoning exemptions in Somerset are required for the Project and whether the present or proposed use of the land or structures is reasonably necessary for the public convenience or welfare.   

The Siting Board will not review the Offshore Wind Resource itself (including the turbine array, related equipment, and a portion of the transmission line) as it would be located in federal waters and therefore is subject to federal jurisdiction and review.  Additionally, the Siting Board will not review the portion of the transmission facilities that would be located in Rhode Island; these will be subject to Rhode Island jurisdiction and review.

Important Dates

This section will be updated as the EFSB develops a procedural schedule for this proceeding.

May 27, 2022:  Mayflower Wind files Petitions with the Siting Board

October 11, 2022:  Siting Board holds Public Comment Hearing

October 25, 2022:  Deadline to Petition to be Intervenor or Limited Participant/Deadline for Written Comments

Description of Project

Mayflower Wind’s proposed Project consists of: (1) two HVDC export power cables with a nominal voltage of approximately 320 kV and associated communications cabling that travel through Massachusetts state waters, proceed below the seabed in Mount Hope Bay and make final landfall at Brayton Point in Somerset, Massachusetts, using horizontal directional drilling (“HDD”); (2) after making landfall at Brayton Point, two HVDC export power cables with a nominal voltage of approximately 320 kV and associated communications cabling continue underground onshore for approximately 0.6 miles to the converter station; (3) a new Mayflower Wind-developed onshore HVDC converter station designed to convert the HVDC power to HVAC to enable interconnection to the existing transmission infrastructure; (4) underground HVAC transmission lines with a nominal voltage of approximately 345 kV connecting the converter station to the existing New England Power Company d/b/a National Grid substation at Brayton Point; and (5) a Noticed Variation, as described below.

Mayflower Wind’s filing identifies two primary alternatives for the offshore export cable corridor (“ECC”) in Massachusetts state waters and landfall locations, as well as two primary alternatives for the onshore underground route from the landfall locations to the Mayflower Wind Converter Station (the Proposed Route and the Noticed Alternative Route), one location at Brayton Point for the Mayflower Wind Converter Station location, and one onshore route between the Mayflower Wind Converter Station and the National Grid substation at Brayton Point. 

Project Filing with EFSB

The petition to construct the Project includes the following information: (1) a description of the Project; (2) an analysis of the need for the Project; (3) a description of the alternatives to the Project; (4) a description of the route selection process and of the proposed route (Proposed Route), the alternative route (Noticed Alternative Route), and a design variation that applies to both routes (Noticed Variation); (5) a description of the environmental impacts of the Project and a comparison of the routes; and (6) a description of the Project’s consistency with policies of the Commonwealth of Massachusetts. 

All documents related filed in relation to a proceeding are posted to the DPU Fileroom.  The Fileroom page for a proceeding represents the official record for that proceeding.  The public can access the Fileroom page for this proceeding at the following link:

Language Services/Accommodations

Reasonable accommodations for people with disabilities are available upon request.  Include a complete description of the accommodation you will need and a way we can contact you if we need more information.  Please provide as much advance notice as possible.  Please allow at least two weeks (14 days) advance notice.  Last minute requests will be accepted, but we may be unable to fulfill the request.  Please send your requests to: Melixza G. Esenyie, ADA and Diversity Manager at the Executive Office of Energy and Environmental Affairs at Melixza.Esenyie2@mass.gov or call 617-626-1282.

Interpretation services for those with limited English language proficiency are available upon request.  Include in your request the language required and a way to contact you if the Presiding Officer needs more information.  Please provide as much advance notice as possible.  Last minute requests may not be able to be accommodated.  Contact the Presiding Officer (contact information below).


Any person desiring further information regarding this proceeding, including information regarding intervention or participation in the adjudicatory proceeding, may contact the Presiding Officer at the following telephone number or email address:

Robert J. Shea, Presiding Officer
Energy Facilities Siting Board

One South Station

Boston, MA 02110

617 305-4246

Useful Information

EFSB and DPU Siting Process

Energy facility siting laws and regulations listing

Energy Facilities Siting Board Handbook (updated 2019) | Guía para fijar la ubicación de instalaciones energéticas (2019)

Siting Related Links



EFSB/DPU Siting Division (617) 305-3525
DPU Main (617) 305-3500


(617) 443-1116


Department of Public Utilities
1 South Station, 5th floor
Boston, MA 02110

Help Us Improve Mass.gov with your feedback