Participating transmission owner per unit costs - 2025

The ISO Generator Interconnection Procedures (ISO Tariff DD Appendix 5) requires participating transmission owners to annually update and publish per unit costs for use during the current interconnection study cycle for estimating the cost of facilities required to interconnect generation. Per unit costs are used to develop the cost for reliability and delivery network upgrades and participating transmission owner’s interconnection facilities. The ISO annually publishes draft per unit costs to its website, holds a stakeholder meeting and allows stakeholders to comment on the draft costs. The ISO publishes the final costs in the March to April time frame. The schedule for this annual process is located in Appendix 5 of the interconnection procedures.