A Swiss canton has installed vertical solar panels on a roadside retaining wall, contributing to its target of generating 40% of its electricity from renewables by 2035.
“This isn’t a big project, but it’s a delightfully creative one, which is why it caught my eye,” writes climate journalist Michelle Lewis for Electrek.
“A retaining wall is dead space, and snow will slide off the panels in Swiss winters.”
German mounting system provider K2 Systems and Swiss contractor Solarmotion installed the 756 solar panels on a 75° inclined retaining wall in the canton of Appenzell Ausserrhoden, in northeastern Switzerland. The glass-glass panels have solar cells encapsulated between two layers of glass rather than one, which gives them an extended lifespan thanks to the added protection from environmental factors.
The panels have peak output of 325 kilowatts, with an energy yield of around 230,000 kilowatt-hours annually, or enough to power about 52 Swiss households. But there is no direct customer for the retaining-wall-generated power. Instead, the canton will supply power to the local grid and get a feed-in tariff in return.
“Especially in the winter months (when consumption and dependence on foreign electricity imports are at their highest), the vertically aligned modules will achieve a very good electricity yield,” said K2.
Installing the panels posed a unique challenge, the company noted, because the mounting structure could not be sunk more than 90 millimetres into the wall without weakening it. The installers used an adhesive technique to get around the issue. The panel components were also anodized for protection because of their close proximity to the asphalt.
Though solar panels have historically been installed mostly horizontally at angles of 20° to 30°, vertical panels are being deployed where horizontal panels don’t fit. For instance, on farmland, vertical panels can more easily accommodate tractors and other farm machinery between rows.
In applications where bifacial panels can capture solar energy from two directions—unlike the Appenzell Ausserrhoden panels, which are backed by a retaining wall—some researchers argue that vertical panels have greater potential than horizontal ones. Vertical panels in this setting can also produce more evenly-distributed energy from morning to evening, whereas horizontal panels tend to have a more dramatic peak at midday that exceeds demand. That could point to a role for vertical panels in reducing reliance on battery storage.