By Michael Yoder

PJM stakeholders last week questioned the scope and timing of the RTO’s proposed initiative for considering storage as transmission assets (SATA) in the Regional Transmission Expansion Plan (RTEP) process.

The RTO is hoping to develop rules by the end of the year for treating storage that would be dispatched to address thermal, voltage or stability violations or to relieve transmission constraints. Other potential uses for SATA include operational performance (mitigating real-time violations not identified in planning studies) and public policy (grid enhancements requested by a state to further its policies).

PJM’s proposed issue charge says it is seeking “transparent rules for stakeholders to understand how PJM evaluates these assets as opposed to an ad hoc evaluation process to evaluate SATA proposals submitted to mitigate baseline RTEP violations.”

During a first read of the RTO’s SATA plan at the April 14 Planning Committee meeting, Adrien Ford of Old Dominion Electric Cooperative (ODEC) expressed concern that the issue charge states that “PJM needs to initiate a stakeholder process” to add the SATA category.

‘Bias Toward Change’

“We often have a bias toward change” instead of giving proper weight to the status quo as an equally viable alternative, she said.

Ford said she hopes PJM and its stakeholders determine whether planning rules require changes and SATA resources are appropriate for transmission. She said ODEC believes that guidance from FERC on the issue is needed, as the current definition of transmission doesn’t include SATA.

“It really seems as though PJM has come to the foregone conclusion that we should have storage as a transmission asset,” Ford said. “FERC really needs to answer the threshold question on whether storage should or shouldn’t be defined as a transmission asset.”

Marji Philips, LS Power’s vice president of wholesale market policy, said the timing of PJM’s proposal was “aggressive” because FERC will be presenting information on SATA in upcoming months that could potentially be utilized in the planning.

FERC has scheduled a technical conference for May 4 on MISO SATOA Proposal Set for Technical Conference.)

The commission has also scheduled a conference on hybrid storage and generation resources for July 23 (AD20-9). (See FERC Sets Tech Conference on Hybrid Resources.)

Philips also contended that evaluating the cost determination methodology for SATA should not be included in the scope of the proposal until it is decided “there is a separate and unique role” for battery SATA. She said SATA could be ruled to be a hybrid asset, making it subject to existing generation rules.

Independent Market Monitor Joe Bowring called the issue charge a “very significant change,” citing several concerns, including why it makes sense to allow transmission companies to treat a type of generation asset as a cost-of-service transmission asset that would compete with market assets owned by competitive companies. “Is it reasonable to have regulated assets competing directly with competitive assets?” Bowring asked, while also questioning whether battery projects treated as transmission would be open to competitive bidding.

“If you’re really going to evaluate this, you have to do it comprehensively, and you can’t do it piece by piece,” Bowring said. “As the proposal is written, other market-based generation assets could be treated as transmission assets by transmission owners.”

Sharon Segner, vice president of LS Power, suggested that the issue charge or problem statement should address whether SATA is an appropriate policy to tackle. Segner previously raised questions about a proposal from American Electric Power to use storage to correct repeated outages on its Falcon-Prestonsburg 46-kV circuit (AEP-2018-AP010). Segner said PJM cannot include non-transmission alternatives such as storage in the RTEP until it has been designated as transmission by FERC. Allowing AEP to win approval of the project under the M-3 process — which is limited to TOs — discriminates against non-TOs, she said. (See LS Power Challenges PJM on MEP, SATA.)

Dave Mabry, representing the PJM Industrial Customer Coalition, questioned the RTO’s proposal to rule issues over dual usage — considering storage both as transmission and as a market participant — out of scope.

Looking for Gaps

PJM’s Jeff Goldberg said the RTO’s plan is intended to evaluate business rules and assess opportunities for the technology. “We want to explore the existing rules and performance measurement and methodology and look for gaps and opportunities in those in order to integrate storage transmission assets,” Goldberg said.

The key work activities and the scope highlighted by Goldberg in Phase I of the process included ensuring the planning criteria address both performance measurement and cost measurement methodologies while also reflecting system operations input to maintain reliability.

The issue charge also calls for development of criteria regarding the size of SATA projects, including peak load, load duration and recharging characteristics.

It also would develop a framework for comparing storage to traditional transmission reinforcements.

Goldberg said modeling processes will be a key element to the project to address a storage asset’s state of charge (injecting power to the grid, recharging or standing by for deployment). PJM wants to be able to conduct sensitivity analyses to expose any reliability deficiencies.

Finally, PJM seeks to evaluate the methodology for determining the total cost of SATA facilities. The methodology would include an initial cost and ongoing maintenance cost; the life expectancy and cost to ensure usable life compared to traditional transmission assets; the consideration of losses associated with charge and discharge cycles; and comparability to existing transmission reinforcement.

“The idea is we want to formalize these as a proposal by taking all those concepts together,” Goldberg said.

Phase 1 of the proposal was not intended to address issues associated with storage as a market participant, Goldberg said, because the terms “energy storage resource” and “capacity storage resource” are already in the Tariff.

Also out of scope for Phase 1 are operational mechanics such as model and telemetry requirements.

PJM’s Aaron Berner said the issue charge is centered on examining PJM’s requirements in relation to the RTEP and how storage could be used as “reinforcements” in meeting compliance obligations.

“In the end, that’s what this effort at this phase is about: Can PJM accept a storage resource as a mitigation project for any of our compliance obligations?” Berner said. “If we can’t get past that issue, we don’t feel that there’s any discussion around whether or not these facilities might be used for any dual use.”

PC Chairman Dave Souder thanked the stakeholders for their feedback and said the committee would discuss the issue further at its May meeting.