Electricity storage has the potential to provide significant flexibility in balancing the grid. The ISO has three participation models that provide opportunities for storage technologies to participate in the wholesale ancillary services market and energy market: pump storage, non-generator resource, and proxy demand resource - load shift resource.

Storage technologies

Pumped storage resources act as load while using energy to pump water to higher elevation reservoirs, and then act like generators by creating energy when releasing water back to lower reservoirs.

Non-generator resources (NGR) have the capability to serve as both generation and load and can be dispatched to any operating level within their entire capacity range.

Proxy demand resource - load shift resource (PDR-LSR) allows storage resources to bid decreases and increases in load. It requires two separate resource IDs for load curtailment, which can bid from the net benefits test threshold price up to the bid cap, and for load consumption, which can bid from less than $0 to the bid floor.

The Participation Comparison - Proxy Demand, Distributed Energy Resource Provider, Storage, and Load Forecast Adjustment is a reference document used to help distinguish between the ISO’s Distributed Energy Resources (DER), Demand Response (DR) and Non-Generator Resource (NGR) market participation model.

New resource implementation process

Participation in the ISO market requires a scheduling coordinator and ISO-certified revenue-quality meters. Bidding in ancillary services requires special certification and installation of direct telemetry. There are also requirements specific to each type of demand participation.

Storage resources as pseudo-ties

Information for market participants who wish to pseudo-tie storage resources into the California ISO Balancing Authority Area. 

The ISO has extended the co-located energy storage features under the completed and implemented Energy Storage Enhancements initiative. See the Energy Storage Enhancements 2022 presentation.

More information is available on the Energy storage and distributed energy resources initiative page.

Related ISO Tariff and Business Practice Manuals

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