CAISO Cluster 15 rules limit study capacity by zone

CAISO's interconnection process reform introduced zonal capacity limits and scoring criteria that determine which requests enter study at all. This is a different instrument from the cluster mechanics required by Order No. 2023, and it operates earlier in the sequence.

The design logic is that studying requests far in excess of deliverable capacity in a zone produces cost estimates that no project will accept and restudies that no timetable survives. Constraining entry keeps study output closer to what the system can absorb.

The consequence for developers is that site selection becomes a queue strategy question rather than a resource quality question. A superior solar or storage site in a saturated zone may be a worse queue position than a mediocre site in an unconstrained one.

The consequence for investors is that zonal information is now material to valuation of development pipelines held in California, and that pipelines assembled before the reform may carry positions that cannot enter study on the schedule underwritten.

What to watch: the distribution of scoring outcomes across zones, which reveals the implicit ranking the criteria produce.