Within the framework of the Innovation and Digitalisation Support Unit (ITE), the Institute of Agricultural Economics (AKI), in cooperation with the AdvisoryNetPEST project, organised an international study visit to Graz-Haidegg, Austria, on 17–18 June 2026, focusing on the application of agrivoltaic (Agri-PV) systems in apple production. With the support of the ITE, a Hungarian farmer and an agricultural adviser also participated in the study visit, enabling them to gain first-hand knowledge of Austrian best practices and experiences.
The two-day event took place primarily at the Haidegg Fruit and Viticulture Research Station near Graz, a public research institute conducting modern variety and production trials while also investigating innovative cultivation technologies such as agrivoltaics.
Agrivoltaics combines photovoltaic electricity generation with agricultural production on the same land, allowing solar panels to positively influence both cultivated crops and the environmental conditions affecting them. Although the concept of agrivoltaics has existed since the 1980s, it was only after the turn of the millennium that experimental facilities were established and research began, first in Japan and later in Germany and France. Its practical application has gained significant momentum only in recent years, particularly in horticultural production.
The research station conducts trials on more than 280 apple varieties and 80 pear varieties, primarily under intensive cultivation systems. The orchards are protected against adverse weather conditions by hail nets, frost protection irrigation, and wind mixing systems. The station also maintains experimental plots of various stone fruits and berry crops.
The agrivoltaic orchard that formed the centrepiece of the study visit was established in 2022 on an area of 5,000 m², of which 2,775 m² are covered by solar panels. The system has a total installed capacity of 340 kWp and produces approximately 385,000 kWh of electricity annually. For comparison, this amount of electricity would cover the annual consumption of approximately 160 average Hungarian households (Source: Hungarian Central Statistical Office, 2024).
A total of 1,134 photovoltaic panels, each with a capacity of 300 watts, were installed. A distinctive feature of these panels is that the photovoltaic cells are not placed directly adjacent to one another but include small gaps, allowing sufficient sunlight to pass through for fruit production. The research station is currently testing panels with different light transmission rates of 30 per cent, 40 per cent, 45 per cent and 49 per cent. The solar panels are installed at different heights depending on the crop: 5 metres above stone fruit orchards, 4 metres above pome fruit orchards, and 3.5 metres above berry plantations.
Dr Thomas Rühmer, Head of Fruit Production Research at the Haidegg Fruit and Viticulture Research Station, presented the results and experiences gained during the four years since the installation of the system.
No plant protection products are applied beneath the solar panels, allowing researchers to assess how different fruit species and varieties develop under the unique microclimatic conditions created by the panels. Each experimental plot is paired with a control orchard of the same age and variety that is protected only by conventional hail nets.
The elevated solar panels provide several protective functions. They keep the tree canopy dry during rainfall, reduce wind exposure, provide shade during hot periods, and limit heat loss caused by radiation during spring frosts. However, unlike conventional hail nets, they cannot provide complete protection against severe hailstorms. In 2023, only one year after installation, an intense wind-driven hailstorm caused extensive damage to the orchard. This demonstrated that the combination of a 3.5-metre row spacing and 5-metre panel height alone could not fully prevent hail damage. To address this issue, researchers attached vertical mesh curtains to the supporting structure. Besides offering improved protection against extreme weather, the dense mesh also reduces bird damage and helps protect against certain insect pests.
From a plant health perspective, the rain-sheltering effect of the solar panels is particularly valuable because it substantially reduces leaf wetness duration compared to the control plots. This lowers the incidence of fungal diseases and reduces the need for fungicide applications. Measurements conducted in May 2025 showed that apple leaves under conventional hail nets remained wet for a total of 198 hours, whereas leaves beneath the solar panels were wet for only 77 hours. Consequently, untreated trees beneath the panels exhibited only 5 per cent apple scab infection, corresponding to an estimated 80 per cent disease reduction.
The solar panels also create favourable microclimatic conditions by cooling the orchard during summer and retaining heat during winter. In June 2025, solar radiation intensity in the apple orchard reached almost 210 W/m² under conventional hail nets, while beneath the solar panels less than half of this value was measured. During winter, the panels help retain heat radiating from the soil. Soil temperature measurements at a depth of 5 cm, carried out between 7 and 14 February 2023, showed that temperatures beneath the panels never fell below −1°C, whereas soil temperatures in the control orchard dropped to −3°C and −4°C.
Thanks to the more favourable microclimate created throughout the year, the most promising results have been observed in peach production. In autumn, peach trees retain their leaves considerably longer, allowing greater nutrient storage before winter dormancy. As a result, the trees enter winter in better physiological condition and produce more uniform and vigorous flowering in spring.
During the visit it became clear that establishing an agrivoltaic orchard, with an investment cost approaching EUR 1 million per hectare, requires careful planning and, above all, a comprehensive strategy for utilising the electricity generated. Feeding surplus electricity into the public grid alone is generally not economically viable. At the research station, electricity is stored in batteries, used for charging electric vehicles, and supplied directly to nearby buildings and production facilities.
Dr Rühmer explained that for orchards located far from infrastructure, it may be difficult to identify sufficiently large electricity consumers or to transmit electricity over long distances. In such cases, in addition to supplying irrigation systems and nearby cold storage facilities, cooperation with neighbouring farms to share surplus electricity may offer a practical solution.
In conclusion, agrivoltaic systems offer numerous agronomic and production advantages for fruit orchards, including improved plant health, enhanced resilience to climatic stress, and reduced plant protection requirements. However, their high investment costs mean that careful economic planning is essential, and profitability largely depends on maximising the use of the electricity generated. Farms that have permanent energy-consuming facilities, such as cold stores, processing plants, logistics centres or office buildings near the orchard, are best positioned to maximise returns by combining efficient energy use with the production benefits of healthier orchards and improved fruit quality.
Author: Gábor ISTVÁN, Institute of Agricultural Economics (AKI)
