Facilities study: engineering and pricing the connection itself
The final study stage, which engineers the interconnection facilities and network upgrades identified earlier and produces the cost estimates and schedule carried into the interconnection agreement.
A facilities study is the last of the study stages in the standard interconnection process. It takes the network upgrades identified in the system impact study and produces engineering detail: equipment specifications, construction scope, a cost estimate at the accuracy level required by the tariff, and a construction schedule.
The study covers both the network upgrades on the transmission system and the interconnection facilities themselves — the switchyard, breakers, protection and metering at the point of interconnection — and states which are the responsibility of the interconnection customer to build or fund.
On completion, the transmission provider tenders a large generator interconnection agreement reflecting the study results. The cost figures in a facilities study report are estimates under the tariff''s stated accuracy band; the agreement governs how actual costs above or below estimate are settled.
Questions
- How does a facilities study differ from a system impact study?
- The system impact study identifies what the network needs. The facilities study designs and prices it, including the interconnection facilities at the point of interconnection.
- What follows a facilities study?
- The transmission provider tenders an interconnection agreement, which the requester may execute, request to be filed unexecuted, or decline by withdrawing.
Sources
- 01
Improvements to Generator Interconnection Procedures and Agreements, Order No. 2023
Federal Energy Regulatory Commission · RM22-14-000 · retrieved 2026-08-09
- 02
Pro forma Large Generator Interconnection Procedures and Large Generator Interconnection Agreement
Federal Energy Regulatory Commission · pro-forma-LGIP-LGIA · retrieved 2026-08-09