Vertical bifacial PV is a technological variant of PV that can be used to primarily generate solar electricity in the morning and evening when oriented towards east and west. Thanks to its wide range of applications, it is attracting interest in agricultural PV or as a fence along shoulders of roads, among other things.
We spoke to Sascha Krause-Tünker, Chairman of Next2Sun, a pioneer in vertical agricultural PV, about the current development curve in this area.
It is particularly popular in agricultural PV because the vertical systems only take up a minimal amount of space, typically less than 1 percent of the surface area. A lot of space is left for agricultural use because we use different dimensions: The vertical dimension is used for power generation while the horizontal dimension is left almost entirely for farming. But that is not its only use. Not by a long shot. We have other vertical applications in our portfolio, such as the solar fence that can be used to enclose buildings or properties. Infrastructure is another area of interest for the future. We are working on a project at Frankfurt Airport. In the future, PV fences along roads and railway tracks could become an important source of electricity, helping to further electrify transportation. According to a study by the Joint Research Center, there is a potential for over 400 gigawatts of solar fencing in Europe alone.
With an east-west orientation, we can create a completely different generation profile. We can use the bifacial modules to capture the morning and evening sun and generate electricity when it is needed, when it is expensive in the electricity markets, and when there is available capacity in the grid. The further you get away from the equator, vertical east-west orientation may actually be better than the standard south-facing system, simply because it reduces losses.
Yes – with this complementary generation profile, we stabilize the grids and counteract price imbalances in the market. There are several factors that can help achieve this, such as flexibilizing demand and deploying storage systems. But we also need to deploy more grid-serving PV. A study by the Fraunhofer Institute has found that for Germany, 70 to 80 percent more vertical PV on free fields would be ideal for optimal grid use. According to research, we could reduce electricity costs in Europe by installing vertical systems, because the grid expansion costs would be lower and, more importantly, less excess electricity would be generated, reducing the total levelized cost of electricity.
Farmers have reacted very positively to them. They come to look at the fields where our systems have been installed – and that has a big impact. We see great acceptance there, because you can still work with big machines without many restrictions. This impresses farmers. Public acceptance of vertical agricultural PV is also higher, because we are not taking up agricultural land. And by growing alternative plants on the strips next to the modules, the land is ecologically improved and monocultures are broken up. Project developers with commercial interests in agricultural PV are less enthusiastic because the power density of vertical PV is lower.
Our hope is for a change in attitude towards vertical PV in the face of grid congestion – but for that to happen, our grid regulations need to be improved. At present, all PV systems are treated the same, regardless of when they generate electricity. Going forward, it will be important to develop regulations and ensure that a distinction is made. And have feed-in profiles assigned that tell me how much capacity is available in the grid and how much I may feed in and when. The bottleneck would probably no longer be space then, but the power grid. This would likely be a breakthrough for vertical PV, as the benefits it offers would be recognized.
Fencing provides us with extensive opportunities in the residential and industrial sectors. We also see potential in parking lots. Looking ahead, infrastructure is certainly of great interest – but a lot needs to happen before we can expand into this area. Power generation must become an integral part of road planning before vertical PV can be used along railway tracks and roads.
What are the challenges of using vertical PV on existing infrastructure such as shoulders?
Right now, the regulations on this are conflicting. The safety distance for shoulders would set the solar fence so far back that it would no longer be part of the road. The effort would be enormous. And if I had to go around and get every single owner of the strip of land where I want to build the fence to sign easements, it would just not be worth it. So it is important to evaluate the following: What are the actual safety requirements? What is actually needed? How can this be solved? There are technical solutions to this, such as guardrails combined with PV. Autobahn GmbH, which is responsible for the German federal highways, also requires some kind of stimulus. The company’s job is clear: providing infrastructure. Power generation, on the other hand, is not part of its scope. The same goes for the German railway company Deutsche Bahn, although it could actually use the electricity generated for its own needs. Implementing such projects will require a change in mindset, which, in turn, will need a push from the government.