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sonnen CEO: ‘We gained credibility in the US through Utah virtual power plant’


Utah is not perhaps a US state people would immediately associate with cutting edge clean energy tech development, but that’s where sonnen’s virtual power plant (VPP) offering took shape.

The US arm of Germany’s biggest residential battery storage provider, owned since 2019 by Shell (although perhaps for not much longer according to recent media reports) has since put VPP projects into operation in California, Puerto Rico, New York, and New England and is prospecting in other markets.

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However, it was the company’s first, near Salt Lake City which has provided the foundation for the VPP value proposition which is progressively moving into the mainstream, sonnen CEO Blake Richetta tells Premium.

According to Richetta, the VPP space is becoming increasingly exciting as it moves from what he describes as a “very esoteric” and perhaps “aspirational”, limited to a handful of projects with specific partners, to something that makes sense to a lot more utilities in the US.

It is, he says, a “breakthrough time” for VPPs of aggregated residential home battery storage systems that are typically, but not always, paired directly with solar PV on customer rooftops.

While the scope for building scale might be bigger in California, especially as the availability of net metering standalone solar ends, or in New York or Puerto Rico, the ‘Wattsmart’ VPP programme with utility Rocky Mountain Power in Utah is now the biggest of its kind in the country, according to Richetta.

“What’s happened in Utah really provides us with our overall foundation,” Richetta says.

“The Wattsmart virtual power plant is now the largest in the country as it pertains to a direct utility dispatched network of behind-the-meter (BTM) batteries that is dispatched every day.” was among media invited to see the first pilot phase of sonnen’s Utah project back in 2018, at Soleil Lofts, a new development residential housing complex.

As sonnen and RMP representatives as well as the site’s solar PV provider Solaria showed the assembled journalists around, one thing was striking: the applications the VPP would serve for the utility were yet to be determined – indeed, that was the main purpose of that initial phase. That said, at 12.5MWh, it is thought to have already been the largest aggregated battery VPP in the US at that time.

‘The VPP dream come true’

Today, Watt Smart provides eight separate grid services. Unlike many other VPP aggregations, the programme doesn’t have any distributed energy resources management system (DERMS) layers in between.

Instead, the batteries are being directly integrated into the operating system Rocky Mountain Power uses to manage its grid: a “big achievement,” claims Richetta.

Proven at Soleil Lofts on a comparatively smaller scale, the VPP “expanded to this service territory-wide program that is now over 40MWh of behind-the-meter residential batteries that are networked and swarm-dispatched every day”.

“This is really the dream come true,” the CEO says.

And where it’s sometimes said in the US that if you can make it in New York, you can make it anywhere, perhaps when it comes to utility innovation and clean energy, if you can prove it in the traditionally more conservative Midwestern states, you can prove it anywhere.

“The American model of the old school, vertically integrated utility, which is what you have in Utah, this is not where it was supposed to be such a pioneering virtual power plant market,” he says.

“…And we’ll think that’s not what anybody would have expected. But this is what happened. So here is a vertically integrated utility, a conservative utility, and they’ve completely in so many ways turned upside down the thought process of what a VPP could be in the US.”

Sonnen launched a new VPP offering for California at the RE+ trade show in 2022. Image: Andy Colthorpe / Solar Media.

Back in Germany, where sonnen has been longer established and operates various different VPP offerings including acting under its own license as a utility, the company has sold 140,000 residential batteries.

“Utah is what gave us credibility in this country. We have so much credibility in Germany, as we’re dispatching tens of thousands of batteries daily. So, for us to be able to go to Utah and do something as sophisticated or even more sophisticated, although with the old vertically integrated utility model, created a new platform for us and it opened the door for California, which is now such a major part of our growth.”’ publisher Solar Media will host the 6th Energy Storage Summit USA, 19-20 March 2024 in Austin, Texas. Featuring a packed programme of panels, presentations and fireside chats from industry leaders focusing on accelerating the market for energy storage across the country. For more information, go to the website.

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