The Alliance for Clean Energy New York (ACE NY) on Tuesday drew 162 people to a virtual meeting to hear solar developers, industry experts and a NYISO official discuss projects that pair solar energy with energy storage.

Timing is crucial, and pairing energy storage with renewables allows the energy to move out of congested pockets, said Bill Acker, executive director of the New York Battery and Energy Storage Technology Consortium (NY-BEST).

“Instead of moving the energy at rush hour, you move the energy off of rush hour and you have what some people call virtual transmission,” Acker said. “Even beyond congestion, you have the situation when you get to very high renewables on the grid, where you literally have over-generation; even if you had the transmission, you wouldn’t be able to use the energy. Again, shifting the time allows you to use the energy.”

Because renewable energy projects paired with storage are proving popular with developers, NYISO in July decided to speed up its hybrid modeling capability, aiming to complete the enhancement in 2021. (See “Exciting Times,” Overheard at NY-BEST’s 10th Annual Meeting.)

Following is some of what we heard at the meeting.

Solar and Wind Benefit

“Storage is increasingly an area of focus for us; it is going to be paired with solar in all forms,” said David Gahl, senior director of state affairs in the Northeast for Solar Energy Industries Association.

In 2019, storage was paired with 5% of solar, “but we’re expecting that number to increase dramatically by 2025. In the distributed space, 25% of all behind-the-meter solar will be paired with storage,” Gahl said.

The growth is being driven in part by the eligibility of hybrids for the investment tax credit and by state goals, Gahl said. “In the utility-scale space … solar is increasingly paired with storage resources, with over 8 GW of commissioned projects that include storage right now. That represents nearly one in five of the contracted projects out there,” he said.

New York’s solar-plus-storage market is being driven by the Climate Leadership and Community Protection Act, which set targets of getting 70% of the state’s electricity from renewables, and deploying 3 GW of energy storage and 6 GW of distributed solar, by 2030. The Public Service Commission laid out the state’s storage deployment policy in a December 2018 order, since updated (18-E-0130).

The New York State Energy Research and Development Authority is working to meet the goals via three pathways: state-subsidized incentives, contracts with the state’s investor-owned utilities and pairing a renewable energy certificate bid with storage, Gahl said. (See NY Utilities, Developers Tweak Storage Procurement Terms.)

In addition to providing the opportunity for more ancillary services, storage makes use of the spilled or “clipped” energy, adds duration and allows discharge at times better suited for the grid or the economics of the unit, said John Brodbeck, senior manager of transmission at EDP Renewables North America. With approximately 700 MW operating in New York, it is the largest owner of wind generation in the state.

“As a wind generator, we’ve been able to reg down for a while. To be able to reg up would be a good thing,” said Brodbeck, referring to ancillary services that help maintain the grid’s frequency. “There’s plenty of problems though … interconnection issues, modeling issues, how does it operate within the market and metering issues.”

NYISO was “pretty swift” to act on paired storage, and the stakeholder discussions quickly came to the concept of co-located storage resources (CSR), which is the simplest form of a hybrid unit: essentially two separate units at the same site, he said.

FERC in August gave final confirmation on most of NYISO’s new storage rules. (See NYISO’s 2nd Storage Compliance Almost Hits Mark.)

“You can get some ancillary services from the storage side, and the intermittent [resource] can charge the storage resource, and those are good things,” Brodbeck said. “The whole AC-coupled, DC-coupled issue seems to have been resolved nicely in NYISO,” with the ISO allowing both AC and DC coupling configurations between intermittent and storage resources. “The current state of the rules for CSR is it does allow a single interconnection request, so we don’t need to have multiple interconnection requests in the queue or in the class year, and the injection can be sized to less than the total electrical capability of the unit, which allows some additional flexibility.” (See Hybrid Resource Developers Ask for Uniform Rules.)

“With 700 MW of wind, our plan is that at some point in the future, we’d be adding storage to most of those sites,” Brodbeck said. “Many renewable sites, especially solar sites, are going to be wanting storage either as part of the original design or added on later. … I think you’ll see storage being added to a large number of units. Our concerns are about having to go back and getting it resized for interconnection, making sure that interconnection plan can be done expeditiously to get online quickly.”

A More Complicated Grid

The evolving grid is going to be much more complicated than the old one-way power flows of the past, said Pete Fuller, principal of Autumn Lane Energy Consulting.

“You’ve got rooftop solar, vehicle-to-grid applications, microgrids, solar, wind, storage, hybrids — you’ve got a lot more things going on out on the grid that are separate and distinct from those big central power plants,” Fuller said. “As I think about hybrids, the real goal here is to create something through co-located or otherwise aggregated resources that somehow is greater than the sum of the parts. It creates additional value, certainly for the developer owner, because that’s what generates the investment and the interest, but also creates additional value for the grid.”

Michael DeSocio, director of market design at NYISO, said that “the energy storage rules that went commercial at the end of August are technology-agnostic.”

The ISO’s new rules focused on storage technologies that are dispatchable, which varies depending on the capabilities of the technology. For example, “if compressed air can inject and withdraw without needing to change state — in other words go offline for a little bit to change the state of its compressors to do that — it could be an ESR [energy storage resource],” DeSocio said.

The model does not exist in the market today for compressed air that needs to go offline between injection and withdrawals, he said.

“It’s something that we’ve thought about building as part of the ESR model but ultimately put aside given that we don’t have any projects in the queue for any of those technologies,” DeSocio said. “We do have a model for limited energy storage resources that’s been around since 2009, which allows flywheels and smaller batteries to provide regulation service. … When we talk about hybrid resources and the co-located model, we’re focused on energy storage that is dispatchable and can provide energy as well as resources that are dispatchable.”