New Subcommittee Focuses on Hybrid Resource Needs

PJM Has More than 13,000 MW of Solar-Plus-Storage Resources in its Queue


PJM and stakeholders have begun a process to identify operational and market enhancements needed to accommodate a growing number of hybrid resources looking to enter the PJM market.

Hybrid resources are composed of two types of generation at a single point of interconnection. Practically speaking, that’s generation and energy storage. And while the model may apply to any type of generation, including wind, the most common pairing in PJM is solar and storage.

More than a quarter of the solar megawatts in the PJM interconnection queue represent solar-plus-storage – signaling a trend for the region and reflecting a nationwide resource shift.

133 Projects in 11 States

PJM has 133 solar-plus-storage projects in its New Services Queue, representing more than 13,000 MW, Andrew Levitt, Senior Market Design Specialist, said Aug. 3 in the first meeting of the new DER and Inverter-based Resources Subcommittee. The group was formed by merging the DER Subcommittee into a new entity that reports to the Market Implementation Committee.

The hybrid projects are located in 11 states. In order of largest to smallest output within a state, they are located in: Indiana, Ohio, Virginia, Kentucky, Pennsylvania, Illinois, Michigan, North Carolina, New Jersey, West Virginia and Maryland.

According to Jason Connell, Manager of Interconnection Projects, solar-plus-storage hybrids began entering the queue in April 2018. The following year, about 5,000 MW of solar-plus-storage hybrids entered the queue between April and September. Since then, another 3,000 MW have been added.

Solar and hybrid solar by state in the PJM New Services Queue.

Hybrids Modeled as One Unit

The first focus of the group will be on solar-plus-storage resources that will be modeled as a single resource for the purpose of offering into PJM’s energy and ancillary services markets.

These new hybrid projects differ from existing co-located fuel types in the PJM footprint, which are modeled as two distinct units because they don’t operate together, said Subcommittee Chair Scott Baker, Senior Business Solution Analyst.

However, solar and storage enjoy a unique synergy, in that they both make similar use of inverters to convert current from DC to AC, Levitt said.

In some cases, the battery component may be able to charge from the grid. In others, it will charge from its paired generation source.

“We’re trying to apply existing rules to these resources where possible – we’re not trying to create a brand-new thing,” Baker said. “But it’s possible that we need to change some rules.”

The subcommittee is aiming to have a report ready for the MIC by the end of the year, he said.

Nationwide Trend

Across the country, a number of factors are driving these projects, including the declining cost of batteries and solar technology, individual states’ efforts to reduce greenhouse gas emissions and the various economic efficiencies of sharing one site, interconnection and electric system.

At the end of 2019, PJM, ISO New England, California ISO and MISO collectively had 56,547 MW of hybrid resources in their queues, according to statistics compiled by Grid Strategies and the Energy Storage Association.

The movement has not gone unnoticed by the Federal Energy Regulatory Commission, which held a technical conference July 23 “to discuss technical and market issues” with hybrids.  

Energy storage resources combined with wind or solar generators offer the ability to “firm” the output of variable resources, increasing their resource adequacy value and offering operational benefits, Levitt testified at the conference.

One of Several PJM Initiatives

The study of hybrid resource needs is one of several PJM and stakeholder initiatives to align market rules and system requirements with the rising availability of renewables and energy storage.

The Capacity Capability Senior Task Force is exploring new methods of calculating how much power resources such as wind, solar and energy storage may offer into the capacity market.

Special sessions of the Planning Committee also are studying the concept of using storage as a transmission asset.

And in June, stakeholders endorsed the creation of the Emerging Technologies Forum to support PJM’s Advanced Technology Pilot Program.