FERC proposes to standardize interconnection procedures

A Broach Reach Power battery storage unit (Courtesy Broad Reach Power).

Editor’s note: This is the third and final installment of a series of articles breaking down the FERC interconnection NOPRCheck out the first article in the series, “Breaking down the FERC interconnection NOPR,” as well as Part 2, “How FERC plans to speed up interconnection queues.”

As part of the Notice of Proposed Rulemaking (NOPR) on generator interconnection, FERC proposed that co-located resources can share an interconnection request, was convinced about the “fuel-based dispatch” to reduce the instances of expensive network upgrades for worst-case interconnection studies, and expanded ride-through requirements to include under-voltage and over-voltage conditions.

This final component of FERC’s interconnection NOPR has three controversial requirements. First, FERC requires transmission providers to terminate an agreement with the interconnection customer if a hybrid resource didn’t operate as intended. Second, transmission companies must evaluate alternate transmission technologies only when the customer requests. Third, interconnection customers are required to provide detailed modeling data to transmission companies; otherwise, the request for interconnection is withdrawn.

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1. Requests for shared interconnection Hybrid projects

FERC defines hybrid resources to be co-located, share a point for interconnection, and go through the generator interconnection process using a single interconnection request.

Before proposing requirements, FERC takes a trip down the memory lane to FERC Order 2003, where it didn’t foresee hybrid resources (energy storage co-located at solar interconnection) taking up much space in current interconnection queues.

FERC proposes to record co-located resources within Large Generator Interconnection Procedures. FERC proposes that transmission providers must allow multiple resources to co-locate at a shared site behind a single point for interconnection and share a single interconnection request. But FERC doesn’t guide transmission providers on what to do with current hybrid resources in the queue.

In addition to defining co-located resources and their ability to share an interconnection request, FERC’s proposal modifies the definition of site control to allow interconnection customers to demonstrate shared land-use for generating facilities that include more than one resource. FERC also proposed that co-located resource are responsible for ensuring that there are no voltage variations among the technologies.

2. Revisions to the material modification procedure

FERC learned from the ISO reports submitted as part the hybrid resource proceeding that PJM considers any addition of an electric storage resource at a solar connection to be a material modifiion.

In contrast, CAISO doesn’t consider it a material modification because any transmission congestion resulting from energy storage injection is considered “non-material” if it doesn’t change the requested interconnection service level.

So, FERC’s proposal requires transmission providers to evaluate the proposed addition of a generating facility to an interconnection request as long as the interconnection customer does not request a change to the originally requested interconnection service level. FERC stated that a transmission provider cannot automatically consider such a request a material change.

FERC is also seeking comments on whether a complete interconnection service study should be conducted in cases where a generator does no alter the final interconnection level. FERC also wants to know what storage does to alter the electrical characteristics of interconnection requests.

3. Access to surplus interconnection services

FERC defines surplus interconnection service as “any unneeded portion of Interconnection Service established in a Large Generator Interconnection Agreement, such that if Surplus Interconnection Service is utilized the total amount of Interconnection Service at the Point of Interconnection would remain the same.”

MISO has received fourteen surplus interconnection requests this year. All of them add storage to existing interconnection requests for solar and wind.

FERC required transmission companies to allow interconnection customers access to the surplus interconnection service process after the original customer has filed an LGIA or when the file of an unexecuted LGIA is made. FERC lifted the restriction that only commercially operated interconnection customers could have access to surplus interconnection capacity.

Grissom Solar is a 6.9MWdc solar and storage project in Enfield NC. Pine Gate Renewables

4. Operating assumptions

FERC suggested that hybrid project operating assumptions should be based on worst-case assumptions. This would include the assumption that electric storage resources will charge during peak loads and then discharge when the load is lighter. FERC was concerned that these worst-case operating assumptions could result in expensive network upgrades during interconnection studies.

FERC referenced Hybrid Resources Coalition and Pine Gates’s comments in modeling hybrid resources. FERC was also sold on Enel’s comments about “fuel-based dispatch” – solar would produce more in the summer, the wind would produce more in the winter, and if both were studied for peak output, then a network upgrade would be triggered. But if solar peak output was only considered for summer months and wind output was only considered for winter months – it would not create the need for that expensive network upgrade. This dispatch is used by both MISO (and PJM) according to FERC.

FERC proposes that transmission providers be required to use operating assumptions for interconnection studies which reflect the proposed operation or co-located resources containing an electric Storage Resource (including hybrids) at the request of interconnection customers.

FERC proposes that interconnection customers be held accountable for statements they make about the intended operation and management of the hybrid resource. The LGIP agreement may be terminated if an interconnection customer fails the to operate hybrid resources according to plan.

FERC also requests comments on whether the proposal should be expanded to include definitions for peak loads, firm and unfirm charging for electric storage resources. Transmission providers will also need to define study criteria, possible interconnect ways, and possible ways to connect for both firm and unfirm charging.

5. Alternative transmission technologies

FERC has yet to decide whether new transmission technologies are viable alternatives for network upgrades. This is because FERC has begun to distinguish between grid enhancing technologies, and alternative transmission technology.

Many comments were made by FERC regarding the ANOPR that grid enhancing technology (GETs) be required to reduce the cost of network upgrades. But for this NOPR, FERC has decided to focus on alternative transmission technologies defined as “advanced power flow control, transmission switching, dynamic line ratings, static synchronous compensators, and/or static VAR compensators.”

FERC does not propose many requirements for this aspect of NOPR. Rather, FERC wants to hear from stakeholders about a few requirements. After receiving a request by the interconnection customer, it requires the transmission provider (or any other transmission provider) to examine alternative solutions during the cluster study. It proposes to revise both the small and large generator interconnection protocols to include alternative transmission technology consideration.

FERC seeks comments on a variety of topics related to alternative transmission technology, including the barriers and whether these technologies could provide the same transmission service as a traditional network upgrade. Also, whether the existing models and studies are suitable.

FERC also requested comments on who should pay for the evaluation of these alternative technologies, whether they should be divided among interconnection customers in a cluster, what is the reasonable number study requests from interconnection customers so that the transmission provider does not get bogged down, as well as whether provisional interconnection services for these technologies should become mandatory.

6. Annual informational reports

FERC also wants to know if you think FERC staff should create an annual report on how transmission providers evaluate alternative technologies.

7. Non-synchronous generating plants: Performance and modeling requirements

Before FERC can expand ride-through requirements for nonsynchronous (solar photovoltaics and wind, fuel cells, and battery storage), facilities, it must discuss past events in which solar failed to perform.

FERC’s timeline started with the first large-scale event in 2016 with the Blue Cut Fire, then followed up with the Canyon 2 Fire Event in 2017, the Angeles Forest and Palmdale Roost Events in 2018, the San Fernando Disturbance in 2020, and multiple events in both ERCOT and CAISO during 2021. FERC is concerned about nonsynchronous units tripping, or entering momentary cessation modes.

An anomaly in FERC’s proposal at this stage in NOPR is that even though FERC doesn’t discuss past modeling issues or challenges, FERC proposed that all interconnection customers seeking to interconnect non-synchronous units provide the modeling information necessary for the transmission provider to conduct interconnection studies.

FERC justifies the modeling requirement based on potentially skewed interconnection costs if the transmission provider doesn’t have the right information to identify interconnection facilities and network upgrades needed to interconnect renewable projects safely.

Before we move on to ride-through requirements, it’s worth noting that FERC proposed queuing projects be withdrawn if an interconnection customer fails after a 10-day grace period to provide data to the transmission provider. FERC is seeking comments on this modeling requirement to determine if it is sufficient and necessary to accurately model non-synchronous facilities.

8. Ride-through requirements

FERC generally follows NERC Inverter Based Resources’ (IBR) performance guidelines when proposing ride-through requirements for new generator interconnection projects. In this NOPR, FERC proposed to expand the definition of “ride-through” from under-frequency and over-frequency conditions to include the ability of the large generating facility to stay connected to and synchronized with the transmission system during system disturbances within under-voltage and over-voltage conditions as well.