How do imports and exports affect resource adequacy?
RA can be estimated for large geographic regions (e.g. Europe) or for a specific administrative or bulk system operator footprint within a region. A system that is part of a wider interconnection has transmission interties (AC or HVDC) with neighboring systems. The degree to which energy imports and exports impact the assessment of adequacy of an interconnected system depends on:
- Certainty of, and availability of, the capacity located in the sending footprint and the reliability of the transmission network transferring the power to the interface.
- The likelihood of coincident scarcity conditions occurring in both sending and receiving systems.
- Contractual obligations that may hinder or fail to promote local system operations, balancing, resource sharing, and priorities.
Several studies have demonstrated that assessing capacity adequacy over a wider footprint reduces the generation capacity required, when compared to smaller subdivisions of footprints, under fully adequate transmission assumptions. However, alignment between regulatory authority and grid regional boundaries is rare.
Forecasts of non-firm imports across AC-connected areas may have significant errors compared to firm, scheduled imports. Non-firm contracts are more likely to be curtailed due to grid conditions. For RA, a prudent approach assumes the availability of generation outside the territory is grounded in firm operational experiences and contractual agreements.