A new, upscale apartment community launches this week in Herriman, Utah, boasting more than a pool and fitness center. Soleil Lofts promises a fully electrified complex with a green energy focus, addressing the region's air quality problem.

Geographic and weather-related factors trap dirty air in the region, leading to the city's unsafe air pollution levels. Local utility Rocky Mountain Power (RMP) is looking to add more renewables, and believes the new apartment complex, developed by The Wasatch Group, could provide one model for developing greener buildings.

Each of the 600 apartment units will come with efficient appliances and a Sonnen battery — powered by solar panels on top of all 22 buildings in the complex. RMP will manage the batteries as a Virtual Power Plant (VPP) capable of operating as a grid resource. Once fully operational, the utility says Soleil Lofts will be the largest residential battery demand response project in the United States.

"In my opinion, this is the most transformative project we've worked on in the United States," Sonnen CEO Blake Richetta told Utility Dive.

That's coming from a company that has installed more than 40,000 batteries globally and already developed multiple VPPs that combine residential energy systems into grid resources. But Richetta, who took the helm at Sonnen earlier this year, said the Utah project stands out for multiple reasons.

"This has never been done before. It is a completely purpose-built community, owned by the developer but the utility is completely managing the solar and battery resources," Richetta said.

The total cost of the Battery Demand Response Project is estimated at $34.3 million. RMP will contribute about $3.27 million towards the storage side of the project and Wasatch is paying approximately $31 million, which includes all of the solar generation. The Wasatch Group

Sonnen and RMP credited the developer for its environmental focus.

"If we tried to do this on our own, it wouldn't have penciled out," RMP managing director Bill Comeau told Utility Dive. "Not for us, or them."

The Wasatch Group will own the solar array and batteries, while RMP will manage the VPP as a grid resource and will be studying its potential integration into the Western Energy Imbalance Market. More than 600 individual Sonnen ecoLinx batteries will be capable of storing 12.6 MWh of energy from a 5.2 MW solar array.

While the VPP is unique, both Sonnen and RMP say it represents a solution that can be replicated.

A 'platform for managing batteries'

The Utah Public Service Commission approved the battery project in June, along with two other demand-side management projects RMP proposed under the state's Sustainable Transportation and Energy Plan Act of 2016.

Residents will begin moving into the apartments next month, although the final Soleil Lofts building will not be complete until December 2020.

RMP pitched the Soleil Lofts development as a battery demand response project that would allow the utility to test an "innovative approach to solar and battery integration, along with advanced management of the grid and peak/off-peak energy use."

Regulators also signed off on automated meter reading facilities and a transportation hub project focused on addressing the costs of high voltage electric vehicle charging.

The Wasatch Group

The utility sees the residential development as something which can be expanded or replicated in its service: RMP CEO Gary Hoogeveen in a statement called the VPP a "platform for managing batteries for other customers we serve, as well."

"The platform idea really excites us to our core, actually creating something that makes a difference and helps the grid," Richetta said. "All over the country utilities talk about these things, but Rocky Mountain Power is actually dong it."

RMP's application for the project said it will allow the utility to "test the feasibility and economic benefit of battery demand response and study behind-the-meter battery behavior for a fraction of what it would normally cost."

Joint financing

Utah power rates average $0.086/kWh, significantly lower than the national average of more than $0.13/kWh. That can create challenges to designing financially-viable energy projects, said Comeau.

"We have some of the lowest rates in the country, so when you talk about trying to get a battery project to pencil out, it required a partnership and a tech solution," Comeau said.

The Wasatch Group is footing most of the bill. The group "started with the firm belief we could build a community that was solving the Salt Lake Valley's serious air quality issues today and in the future," CEO Dell Loy Hansen said in a statement.

The total cost of the Battery Demand Response Project is estimated at $34.3 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.

Wasatch is paying approximately $31 million for its portion of the project, which includes all of the solar generation.

"Utah is unique. It sits in a bowl," said Comeau. "We have air quality issues, but we really have some passionate people in our community."

VPPs becoming more common

VPPs allow utilities to aggregate and control behind-the-meter resources, and the strategy is becoming more common in the United States as well as globally.

In June, AutoGrid announced it would partner with a Japanese energy services and trading company, ENERES Co. to create what could be the largest VPP in the world by number of connected assets. More recently, Sunrun announced a 295 MW residential solar-storage VPP proposal for Los Angeles.

"This has never been done before. ... Solar controlled by the utility to benefit the community." Blake Richetta CEO, Sonnen

In Arizona in 2017, ​Sonnen teamed up with Mandalay Homes to build 2,900 homes in Prescott Valley, Arizona, and equip each with batteries. The company launched its SonnenCommunities in 2015 in Germany, where it is headquartered.

"Sonnen's perspective is very global when it comes to residential energy storage," said Richetta. But its approach varies, depending on location. In Germany, the company has retrofitted 400 year-old homes with batteries in some instances.

"The master planned apartment community is a relatively American thing," Richetta said, which makes Soleil Lofts unique. "This has never been done before. ... Solar controlled by the utility to benefit the community."

The Wasatch Group

For RMP, the utility is looking for the next generation of demand response products to help integrate more renewable energy.

"The grid will be utilized optimally through daily peak usage reductions, which could lead to cost savings for customers and reduce transmission congestion during summer peak loading periods," RMP said in its application.

The project also provides a renewable and battery grid management solution that RMP will learn from in order to inform future microgrid solutions. The utility says the batteries will provide backup power during grid power outages for each individual apartment, while also providing experience operating behind-the-meter energy storage that will help to optimize rate design and pave the way for large-scale integration storage

"We view this project a lot differently than a one-off," Comeau said. "We're creating a platform where we will be able to utilize and dispatch batteries throughout our whole territory. We're looking for solutions to help manage the grid and integrate renewables."

While RMP considers this a "customer-driven project," said Comeau, "we see value from all sides. We'll be able to dispatch it and use it as a grid resource."