of potatoes between PV modules – noe.ORF.at

In Guntramsdorf, the sun is used twice. The University of Natural Resources and Life Sciences Vienna (BOKU) planted potatoes at the Wien Energie site among the PV modules. “They have a similar yield or only slight losses compared to cultivation without photovoltaic cells,” says Alexander Bauer, an employee in BOKU’s agricultural engineering department. But long-term studies are still missing, and it is not yet possible to make a reliable recommendation as to which crops will grow well in such systems.

“It depends on the requirements of the crops and the weather. In a hot and dry year, Agri-PV has a positive effect because the units cast shadows. The system can also affect wind speed and evaporation,” explains Bauer. Plants that need a lot of sun, such as corn, will not develop well between PV modules.

The plant adjacent to the highway supplies electricity to about 1,200 homes. “For us, the results have been that the cables that are harnessed from the modules to the ground and then from the individual rows of panels have to be laid differently so that the farmer does not damage the cables when driving the devices here,” Herbert Brandner, Head of Renewable Energy at Wien Energie.

In Guntramsdorf there are units oriented obliquely to the south as well as vertically oriented towards the east and west. “If you only have south-facing panels, the biggest peak in generation is noon. With this mixture, you even have power generation throughout the day, which relaxes the grids as well,” says Brandner.

Solar energy will sixfold by 2030

There is still a lot to come for these networks with the transition of energy. According to the calculations of the Austrian Energy Agency, 2.7 TWh of electricity must also be generated by photovoltaic cells in Lower Austria by 2030 in order to achieve the energy transition. The energy transition is understood to mean the tipping point at which Austria can fully and independently supply itself with green electricity. Currently, 0.48 TWh of solar energy is generated in the federal state. So the value should increase nearly sixfold over the next eight years.

Federal states bear a lot of responsibility for this expansion, as they define spatial planning for example. The state of Lower Austria is currently working on a zoning plan for photovoltaic systems – that is, specific areas in which photovoltaic cells will be implemented in open spaces. Preference should be given to used or polluted areas, such as landfills. High quality agricultural land will not and should not be used for PV systems in the future. A zoning plan should be available in the summer.

Interested parties note that PV systems are booming not least because of the sale of modules and often the entire required installation kits are reserved for months. Recently, Netz Niederösterreich said that many small systems feeding in would destabilize the grid – more on this in the PV boom leading to grid problems (noe.ORF.at; May 6, 2022). With larger systems like the one at Guntramsdorf, this isn’t a problem because it feeds a higher-level network, says Herbert Brandner.

floating electricity

Not only can the soil provide more electricity in the future – a company based in Amstetten is developing photovoltaic modules for water surfaces. Eight units have been tested on a gravel pond in Pöchlarn (Melk region) since last summer. According to the company, it is wind and wave resistant and suitable for fresh and salt water. In Austria, the company sees the potential above all in cabinets. Effects on animals and plants in lakes and ponds have not been researched.

Photo series with 3 photos

In terms of research, the photovoltaic cells found in farmland have already advanced. Guntramsdorf was one of the first attempts in Austria in 2019. With the knowledge gained there, Wien Energie built a PV system in Vienna-Donaustadt that was three times larger. “Winter wheat, spelt, and soybeans are grown there,” Herbert Brandner says.

PV on rooftops is not enough

80 percent of Wien Energie’s PV systems are on rooftops, and that’s still the preferred use, “However, we need every opportunity to generate electricity this fast in order to achieve the energy transition, because that’s not even ten years old,” he says. Brandner.

This wouldn’t be possible with rooftops alone. “It is important to use every logical area to have a range of power plants in Austria so that we can power ourselves independently.”

Even if one has good experiences with the combination of agriculture and photovoltaic in Guntramsdorf and Donaustadt: no two areas are the same, “Agriculture does not succeed in developing experiments for a year or two and then you know how to do it. We need five,” says Alexander Bauer. To ten years of experience to know what is best and where to be careful.” But what speaks well of open space photovoltaics: “We do not close any area, the systems can be completely dismantled and after use it becomes pure farmland again.”