Southwest Power Pool files to tweak rules to help hybrid resources participate in market

Southwest Power Pool is seeking to change its rules so that hybrid resources can register as a single resource and participate in the SPP market, according to a Dec. 20 filing with the Federal Energy Regulatory Commission.

The move is significant because hybrid resources are rapidly growing in interconnection queues, due in part to lower costs for battery, wind and solar resources and the federal investment tax credit, according to a FERC white paper on hybrid resources.

SPP in August implemented its rules to help electric storage resources to participate in its market. These rules created a new participation model called the market storage resource model. As storage resources started registering, SPP realized that hybrid resources could be registered as an MSR, but its rules did not explicitly address this type of registration.

Hybrid rules

In response, SPP has filed proposed changes that explain that an electric storage resource paired with a generating resource behind the same point of interconnection can register those resources as a single resource called a hybrid storage market resource. An HSMR can register as any resource type for which it meets the physical and operational requirements, including the MSR model, according to the proposal (ER22-684).

Hybrid resources directly connected to the grid will still have its component resources modeled separately, despite being dispatched and settled as a single resource, SPP said. "These HSMRs are more likely to be larger resources and information about the operation of the underlying units will be important for visibility of the operators for reliability reasons," SPP said in a footnote in the proposal.

Modeling needs

Specifically, SPP will need visibility into the actual output from variable energy resources to ensure proper forecasting, according to an SPP white paper on hybrid resource modeling. And SPP needs visibility into the state of charge of electric storage resources in order to assess reliability, the white paper said.

Hybrid resources that are not directly connected to the grid will be considered distributed energy resource aggregations and be addressed under SPP's compliance filing for DERs, SPP said in its FERC filing.

Prior to the filing, SPP considered several options to address hybrid resources, SPP's white paper said. Some stakeholders wanted SPP to implement multiple options to increase the flexibility available to hybrid resources, but SPP argued that choosing a single option would decrease the overall cost and performance impacts to the market, the white paper said.