Capacity Requests

Capacity Requests

Capacity Requests (aka ICAP, UCAP, Peak Contribution) 

05/31/2024 - Effective on 05/31/2024, the capacity values transmitted via EDI 867 Historical Usage are the values for the 2024 Power Year (June 1, 2024 - May 31, 2025)

12/19/2011 - Capacity values are NOW included in the EDI 867 Historical Usage data. Licensed Suppliers should use the HU request to obtain capacity data.  Licensed Aggregators not using EDI may still obtain capacity data using the method outlined below.

Submitting Capacity Requests

Capacity requests may be submitted to UI by CT licensed aggregators and CT licensed suppliers not registered with UI as prescribed in CT DPUC Docket No. 07-01-21. Capacity requests are submitted by email to in a MS Excel file. Results are returned by email in a MS Excel file.


How does UI determine individual customer and ultimately the Load Asset capacity values?

ISO New England, Inc. (“ISO”) notifies UI and other Market Participants, of the day and specific hour and load value to be utilized for Forward Capacity Market Annual Peak Load reporting and provides UI with both the New England Hourly System Peak and the corresponding UI System Peak load value.  UI provides this information on its Historical UI Load Data page in the file called UI_ISO_Peak_Contribution_reported_values_SS_and_LRS_2007-2023.xls .  The UI System Peak provided by ISO is the value of all non-Station Service Load in the peak hour plus Demand Response reconstitution, if any.  


Peak Contribution by Load Asset Daily Reporting Value Process

The following is the process utilized by UI to generate the daily reporting value for Peak Contribution by Load Asset:

  • A load settlement is completed for the Forward Capacity Market Annual Peak Load peak day.  This load settlement is done after the updated class average load shapes (Load Profiles) for the peak day year have been updated/loaded into the UI load settlement system.  Actual class average load shapes for the specific peak day are utilized in this load settlement. 
  • The load settlement for the Forward Capacity Market Annual Peak Load peak day calculates values for the peak hour for each customer that existed on the peak day.  The sum of the individual values for each customer in that peak hour will exactly equal the total UI Forward Capacity Market Annual Peak Load hourly value.
  • New customers, added since the peak day, are assigned the class average value (please see the file link below).
  • Peak Contribution values for those that leave the system are not used in the daily calculation. 
  • Daily, the Peak Contribution for each Load Asset is calculated by summing the value of the currently active individual customer peak contributions mapped to that Load Asset.  Daily, the sum of the Peak Contribution values for all reported Load Assets must equal the UI System Peak.  Any difference, positive or negative, is distributed to each Load Asset on a pro rata basis.


Additional information regarding capacity requests:

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