Harvesting Energy Security is Always Vintage: Winery Microgrid Creates Power Resiliency in Heart of Napa Valley

There’s a scene in the film, “Sideways,” perhaps one of the best movies ever about Napa Valley wine, in which main character Miles Raymond is asked why he is so into pinot noir.

Miles is the consummate wine nerd and snob. He waxes poetically about the variety, from its vulnerabilities to the value of its meaningful sustainability.

“Only the most patient and nurturing of growers can do it, really,” Miles, played by Paul Giamatti, tells Maya. “Only somebody who really takes the time to understand pinot's potential can then coax it into its fullest expression.”

In the real Napa Valley, beyond Hollywood's hype and yet truthfully rendered in storybook fashion, a winery is focusing on taking the same, careful and yet progressive long view into its energy situation.

Domaine Carneros has invested in a solar-storage microgrid and expanded on-site renewables to both reduce carbon emissions and energy costs.

The winery’s leaders and staff hosted microgrid developer Schneider Electric, service providers and neighboring vintners who wanted to learn more this past week and join in to celebrate the anniversary of the microgrid’s first full calendar year of operation. The project first entered operations in July 2023.

Seeking a harvest of energy resiliency

Domaine Carneros CEO Remi Cohen, on the right, walks with Zak Miller, winemaker.

“We are really happy with the results,” Remi Cohen, CEO of Domaine Carneros, told Microgrid Knowledge in an exclusive interview on the day of the microgrid celebration at the winery. “Energy is not getting cheaper so we’re always looking at ways to cut energy costs.”

Energy resiliency also is a key foundation for a business which must rely on uninterrupted power during critical seasons such as harvesting, processing and hospitality periods.

Domaine Carneros, founded in 1987, is known for its sparking wines such as Brut Rose and Vermeil Demi-Sec, as well as limited production of the aforementioned pinot noir. Founding CEO Eileen Crane handed over the reins of Domaine Carneros to Cohen in 2020, around the same time that it gave the go-ahead to Schneider Electric to build the on-site microgrid.

The project expanded the winery’s already decades-old rooftop solar and added ground-mounted solar, battery storage and backup generation.

“The very first conversations (about microgrid adoption) actually go back to 2014 after the (South Napa) earthquake,” Cohen recalled. “The 2017 wildfires very much drove our decision making. . . One event could flip the whole value proposition.”

Domaine Carneros self-financed the project, while utilizing available grants and incentives to reach an acceptable return on investment (ROI) projection. The microgrid’s solar and battery storage elements helped supply about 77 percent of the winery’s power needs in the first six months of operation in 2023, and about 70% to 80% for all most of 2024 .

The ROI model anticipates that Domain Carneros will get its full return on the investment within 10 years, maybe sooner if utility electricity costs continue to rise as they have in California, without accounting for the cost of outages.

“There’s critical steps along the way where we cannot be without power,” Cohen pointed out. “If we ran out of power during harvest and didn’t have the backup generator, we cannot process the fruit and it gets overripe. . . If we lose temperature control during maturation and the aging process, if we don’t have the right temperature in the cellar, there are those quality issues. . . That’s not to mention impact to the hospitality functions if we run out of power.”

Proving the microgrid's mettle and ROI

A view of rooftop solar at the Domaine Carneros winery in Napa Valley.

And the past year already has proven the microgrid’s mettle and value with several small but still impactful outages. At one point, an automobile accident took out the nearby power substation for an entire day, but Domaine Carneros kept on keeping on.

“We’ve had smaller outages; lots of them,” Cohen said. “We’ve had birds take out power lines.”

Having a microgrid answer to these unplanned outages drove the winery leadership’s enthusiasm to stay the course in building out the project over a challenging three-year period that included supply chain issues brought on by the COVID pandemic.

“It really helps when the customer is that excited,” Jana Gerber, North American head of microgrids for Schneider Electric, told Microgrid Knowledge. “For microgrids, it also takes some nurturing. We had about six months to fine-tune the thresholds and sequence of operations correctly.”

Schneider Electric was leading the project from the beginning, but later brought in PowerFlex, which helped design and the integration of the solar and battery storage components. PowerFlex’s work including installation of new SolarEdge inverters.

"The addition of DC-optimized inverter technology to the microgrid enhances the winery's rooftop solar system by enabling module-level monitoring, optimized energy production through maximum power point tracking, and advanced safety features to protect the roof, property and personnel with thermal detection capabilities powered by Sense Connect technology," John Carroll, vice president at C&I North America for SolarEdge, said.

The 614 solar panels, which are mainly on the roofs of several Domaine Carneros buildings but also include one ground-mounted array near a vineyard section, total 427 kW at capacity. The 250-kVA battery and backup generator aided the microgrid in generating close to 740 MWh of electricity capacity in 2024.

“It’s exceeding expectations on a lot of fronts,” winery CEO Cohen said. “The battery could provide us a couple of hours even without the generator but now can provide much longer than that. I think it’s an exciting investment for us. Domaine Carneros is excited to be a leader in terms of wineries.”

Domaine Carneros and Schneider Electric invited some of the neighboring vintners to visit the microgrid up close and begin conservations on whether this type of on-site power is right for them.

“This really crosses three different types of business segments on the single property,” Samantha Childress, director of microgrid partners strategy at Schneider Electric. “They are an agricultural producer, food and beverage packager, and a retail space with their beautiful tasting room."

“This means they can serve as an example to many different energy prosumers facing similar challenges,” Childress added.”

The on-site power layout at Domaine Carneros also has four solar-powered electric vehicle charging stations for guests.

Sustainability is the heart of the wine-growing business. Domaine Carneros uses all of its rainfall collected and diverted into an irrigation pond so it can avoid drawing from groundwater wells. It bottles on-site and reuses packaging, reducing consumption of trees.

“We really believe in conservation,” Cohen pointed out.

Many of the components that make up the Domaine Carneros project were tested and validated at the company’s new microgrid architecture lab in Andover, Massachusetts. This microgrid was developed with the company’s EcoStruxure technology, but leaders who helped make the winery project happen believe it also lays and laid a strong foundation for the company’s new standardized Microgrid Flex architecture, which is designed for being quicker to deploy.

“A lot of this translates,” Childress noted. “The sequence of operations started here (in Andover) and that’s what we tested and validated. It’s a foundational project that we aim to replicate."