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Transmission Interconnections

Is a transmission interconnection right for me?

The rules for interconnection depend on typical voltage and MWs.

Voltage Less than 69 kV Greater Than or Equal to 69 kV
MW 200 kW – ~20 MW
Greater Than ~20 MW

The ISO New England tariff only applies to transmission-interconnected projects participating in the markets.
Distribution-interconnected projects will follow the applicable state interconnection process. If a distribution-interconnected project triggers a transmission study, ISO New England planning procedures and tariff apply.

Beyond supporting your project through the interconnection process, Eversource Transmission Interconnection Services can provide additional support through tailored interconnection plans, commercial and other supporting agreements designed to meet your organization’s individual needs. Read the pre-studies and assistance section for additional details. 

Interconnection Process

Interconnection Resources

This information is being provided for educational purposes only and should not under any circumstances be relied upon for business, financial, planning, or operational decisions.  Interconnection rules and requirements, including applicable state and federal laws and regulations, are complex and subject to change. 

Prospective interconnection customers and other interested parties should consult with their own retained experts and attorneys to navigate this process.  While the information provided here is accurate to the best of Eversource’s knowledge as of the date below, it is nevertheless a gross summarization of an extremely complicated and often expensive process.

If there is any conflict between the information provided herein and any applicable laws, regulations, ISO New England processes or other controlling interconnection documents, those documents shall control.  Nothing herein should be construed as legal, business, engineering or other expert advice.  

Nothing herein shall be construed as a representation that Eversource or its affiliates will provide any service or product under the interconnection process unless subsequently agreed to in writing.  If you have any questions or concerns regarding the information provided herein, please email

Last updated April 1, 2023