The California ISO has updated its energy storage and distributed energy resource (ESDER) initiative, RTO Insider reports.
ESDER’s proposal includes a less restrictive methodology for assessing the demand response potential of aggregated retail customers, essentially a four day look-back for residential accounts, rather than 45 days. CAISO is also working with the Public Utilities Commission to rework station power rules for battery storage.
CAISO’s changes are scheduled to be reviewed by the Energy Imbalance Market on July 13 before being submitted to the ISO’s board of governors at its July 26-27 meeting.
California leads the nation in distributed energy resources, but integrating those resources into the grid is not easy. On the regulatory front the integration process has resulted in a profusion of rules the CPUC is trying to tame with a DER Action Plan.
CAISO is also working toward a smoother integration of DERs. In its latest update, the agency is working toward a brighter line between station power and wholesale charging energy when it comes to energy storage.
The challenge is distinguishing between wholesale charging energy that will be resold and “station power,” which is energy consumed to operate a generator. The ISO has proposed a simpler definition that defines station power as energy used to serve a resource’s own load that is settled under a retail tariff.
CAISO is trying to distinguish between the two because it is trying to avoid storage resources from getting charged twice at the wholesale and retail level. One way of addressing the issue, the ISO said, would be to require wholesale load and retail load to be metered separately.