On June 2, 2016, FERC approved revisions to the California Independent System Operator's open access transmission tariff that facilitate the participation of small, distribution level energy generation, storage and demand-related resources in the CAISO wholesale energy and ancillary services markets. For individual generators, the CAISO tariff sets a minimum capacity of 0.5 MW to participate in the CAISO markets. The revisions approved by FERC permit smaller distributed energy resources (DERs), including distributed generation, energy storage, dispatchable load (such as pumping load that can increase or decrease its consumption), and plug-in electric vehicle charging stations, to form aggregations of 0.5 MW or more that are eligible to participate in CAISO energy and ancillary services markets.
A copy of CAISO's filing can be found here. A copy of FERC's order can be found here.