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Transmission Rules, Rates and Tariffs

The interconnection process is governed by the ISO New England OATT (Open Access Transmission Tariff). The following schedules are contained within the OATT.

Schedule 22Schedule 23Schedule 25
Standard Large Generator Interconnection Procedures Standard Small Generator Interconnection Procedures Elective Transmission Upgrade (ETU) Interconnection Procedure
Generating facilities that are more than 20 MW Generating facilities that are 20 MW or less New or upgraded transmission facility that the requesting entity has agreed to pay all associated costs

During the interconnection process, a determination will be made whether the upgrades associated with your project are pool transmission facilities (PTF) or non-PTF.

Non-PTF may require Local Service. Local Service over the non-PTF includes either Local Network Service (LNS) and Local Point-To-Point Service (LPtPS). Schedule 21 of the OATT defines how the Participating Transmission Owners provide LNS and LPtPS. Consult Transmission Service Applications and Schedule 21 - Local Service of the OATT for additional information on Local Service before making any reservation. 

Note: Generators are not required to make reservations in OASIS for Schedule 21 service, however, if reservations are made, charges will be based on the current transmission rates for the term of service reserved.  Generators without a reservation will be charged based on their hourly usage of the Non-PTF system multiplied by the hourly on and off-peak rates as applicable. 

The list of transmission substations subject to Schedule 21 Local Service charges can be found below. Interconnections at our other system locations not included in this listing may also yield Schedule 21 Local Service charges, a conclusive determination would be performed upon the completion of an interconnection request. This listing may change from time to time.

Additional Resources

Planning Procedure No. 5 (PP05) - Additional technical guidance on the interconnection process

Open Access Tariff - Open Access Transmission information available on ISO-New England's website

OASIS - Eversource's page on the Open Access Same-time Information System (OASIS) website

Required Postings

Open Access Transmission Information - Information pertaining to FERC Order 890 and 676-E

Transmission Rates - Current Eversource open access transmission service rates in Connecticut, New Hampshire and Massachusetts

FERC Order 717 Requirements - Information and disclosures pertaining to FERC Order 717 for Connecticut, New Hampshire and Western Massachusetts transmission

Transmission Interconnections

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