Finding a solar contractor that offers one service and one service only is rare nowadays. Out of necessity, installers are developing post-installation maintenance plans, learning to install roofing, pairing EV chargers with PV and adding many other types of complementary services to fill new gaps as this industry grows.

Following that trend, a large-scale contractor from Novato, California, had an idea for a ground-mount solar structure, and decided to build the solution itself instead of pitching the idea to an existing manufacturer. Sunstall (No. 75 on the 2023 Top Solar Contractors List) debuted Sunzaun, its proprietary vertical solar racking, in 2022 on a solar project built at a California vineyard.

“Zaun” is the German word for fence, and that is exactly what Sunzaun is meant to be: a solar-generating fence.

In 2019, Sunstall CEO Helge Biernath saw examples of vertical solar fencing, but found those racking systems were customized for each project and made with more expensive and less efficient means than a manufactured solution would offer. Sunstall was founded in 2011 as an installation company specializing in ground-mounted projects and has worked with a range of racking and tracker foundations. So, Biernath said, developing this solar racking in-house made sense.

“When you’re working for 12 years in that space, I mean, you’ve seen it all. We’ve been from the beginning part of the design of multiple [racking] systems,” he said.

A lot of the interest in Sunzaun comes from its potential for dual-use, like “agrivoltaics,” or the symbiotic pairing of a solar installation with agriculture. Certain plant species thrive in environments with partial shading, and since it is a fence covered in solar panels, Sunzaun will cast shadows. Yet Biernath hopes developers will find many other applications for Sunzaun too.

“I think you need a little bit more in this niche than just ‘you sell the solar racking.’ It has to be a solution-driven approach,” he said. “Agrivoltaics is one piece of the puzzle. We call it solar architecture. Is it now residential as a fence? Or is it something along I-5 because we need the whole freeway system full of vertical solar, because we need every electron for every car if we go to EVs?”

Sunzaun is designed to host bifacial solar modules, and because it’s a vertical racking, there is an expected performance cut when compared to a solar array installed at more optimal tilt-angles. Vertical installations have historically performed better in northern latitudes, where they’ll have a steadier output compared to the “duck curve” of midday sun from south-facing arrays.

But Biernath believes wherever solar can be installed, it should be installed, and solar fencing can fit into many places.

“It’s not as efficient as the perfectly adjusted system,” he said. “We get that, but it doesn’t matter. We need more electrons.”

Sunzaun is still in its early stages of public availability. The California vineyard array is its first and only project so far, but the racking has been wind-tested and is currently undergoing UL certifications. Biernath said development is underway on other arrays using the vertical racking.

Sunstall will continue working on large solar projects as an installation subcontractor and hopes to eventually install the solar fencing for customers as Sunzaun reaches greater public availability. Biernath hopes clients will see the potential in Sunzaun and come to the contractor with unique ideas for vertical solar projects.

“Give the people just the concept in general and wait for the ideas to come of what they see for their business,” he said.

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This story was featured exclusively in our 2023 Top Solar Contractors issue. See the issue and full list of top U.S. solar installers here.