As distributed energy increases on the grid, many utilities are looking for ways to leverage behind-the-meter solar, especially when paired with energy storage.

An innovative project in Utah points not just to future uses for energy storage, but also how utility involvement can make the resource viable.

The Soleil Lofts complex in Herriman, Utah, would not have been possible without a unique partnership between Rocky Mountain Power, technology partners and real estate developer Wasatch Group, according to the participants.

When completed, the 600-unit project outside of Salt Lake City will aggregate solar arrays from each building with a Sonnen battery in each apartment. Resources Capacity Rooftop solar 5.2 MW Residential storage 12.6 MWh EV charging ports 150 vehicles

This Virtual Power Plant (VPP) is still under development but the first residents moved in at the end of summer. The 600 Sonnen batteries will provide backup power to residents and be dispatched onto the grid as needed by RMP, a subsidiary of PacifiCorp.

Soleil Lofts is "the most transformative project we've worked on in the United States," Sonnen CEO Blake Richetta told Utility Dive over the summer.

Utilities are looking broadly at the benefits of energy storage, alongside the continued growth in renewable energy, according to Bill Comeau, RMP managing director. But batteries can still carry a hefty price tag relative and he acknowledged there are "cost challenges." The solution remains relatively nascent, and, according to multiple stakeholders, it's difficult to make a newer project price competitive in areas like Utah, which already have low energy price conditions.

"If utilities can provide battery solutions that meet overall grid management needs for customers that could include battery demand response programs with incentives then the invest may be easier to pencil out." Bill Comeau Managing director, Rocky Mountain Power

"Battery solutions and technologies are still being developed and are not standardized for use by customers and utilities, making it difficult for regulated utilities to recover costs for new technologies," Comeau told Utility Dive in an email. To increase the large-scale adoption of batteries, early adopters and utilities will need "incentives to innovate."

That includes support from regulators to recover costs for batteries, Comeau said, as energy storage systems "provide the foundation for building grids that are more resilient at the local level."

Roughly half the cost of the solar and storage components will be earned back in federal, state and utility subsidies, according to Wasatch.

The project is a purpose-built community, with the energy assets owned by Wasatch, but managed by the utility both for residents and the broader electric system.

The total cost of the battery demand response project is about $34 million, with approximately $12 million for the purchase of the batteries. RMP will contribute about $3.27 million toward the storage side of the project, while Wasatch is paying approximately $31 million for its portion of the project, which includes all of the solar generation.

The Wasatch investment was key to advancing the project, which officials say is on track and proceeding as planned.

"Having the right partners is critical for the success of innovative projects," Comeau said.

Sonnen's batteries are paired with an energy system designed by solar developer Auric Energy. RMP says it required the entire group to execute the project.

"It took all parties, the developer, solar installer and the utility to give and take throughout the process," Comeau said. "Trust was established early on ... no one got everything they wanted but at the end of the day everyone benefited."

The project can be a model for deploying similar grid resources, the developers say. "We do see this as a blueprint for developing future partnerships," a Sonnen official said via email.

Using the batteries to provide broad grid benefits, ultimately, is key.

In addition to utilizing the VPP as a grid asset, RMP will also be studying potential integration into the Western Energy Imbalance Market.

"If utilities can provide battery solutions that meet overall grid management needs for customers that could include battery demand response programs with incentives then the invest may be easier to pencil out," Comeau said.