As the world races to meet renewable energy targets, a groundbreaking approach is emerging at the intersection of agriculture and solar power—agrivoltaics. This innovative strategy involves the installation of solar panels above crops, presenting a dual solution to optimize land use for renewable energy and enhance the resilience of food systems against climate change impacts.
In dryland climates, agrivoltaics has demonstrated increased water use efficiencies beneath solar panels, providing crucial adaptation benefits for crops (1). Combining this approach with smart farming practices could therefore make it a promising avenue for sustainable development.
To achieve the renewable energy targets, solar photovoltaic (PV) capacities in many developed countries must be scaled significantly. Germany for example faces the ambitious task of expanding its solar PV capacities from currently 70 to 215 GW. To achieve the required target, Germany’s Ministry for Economics and Climate Mitigation assumes that 50% of the additional capacities will need to be at the utility-scale (2), which corresponds to an area roughly equivalent to 300,000 football pitches. Although this represents only 0.35% of Germany’s surface area, opposition to large-scale renewable energy projects often arises at the local scale.
Meanwhile, conventional agriculture grapples with important challenges, such as soil degradation and water deficits due to intensive farming practices and climate change. Reduced summer precipitation levels lead to crops increasingly struggling with water deficits, considerably impairing food production. During the dry summer of 2018, major harvest losses of up to 70% translated to an economic cost of 2.5 billion Euros in Germany (3).
Another issue is the loss of insect biodiversity, which is declining at alarming rates and poses another threat to stable food production, as a significant percentage of crops grown in Europe rely on insect pollination (4). Notable drivers were found to be habitat loss and intensive farming practices (5). For instance, out of 60 bumblebee species, 48 experienced a decrease in abundance over the past 136 years (6), particularly after 1950 with the widespread uptake of chemical pesticides.
How can crops thrive beneath solar panels?
While numerous studies have explored how growing crops beneath solar panels affects yields (1, 7, 8), I delved into a new angle in my Master’s dissertation project (9): how sustainable land management practices could enhance the cultivation of crops under solar panels. By analyzing the introduction of habitat-enhancing land use types, such as hedges, trees, and grasslands, into agricultural fields, I modelled the impact on four key ecosystem services (10 - Figure 1). This approach not only sheds light on the potential for agrivoltaics to contribute to climate change mitigation and adaptation but also opens up new avenues for optimizing the environmental sustainability of this climate solution.
Integrating habitat-enhancing land management practices with traditional farming practices has shown promising results, particularly in boosting water retention and enhancing insect pollination. Compared to crops, these land use types have much longer rooting depths which contribute to enhanced soil stability and improved water retention levels – a notable benefit with increasing drought risk due to future climate change impacts. Habitat-enhancing land use types also provide a considerably greater abundance of nesting and floral resources for insects such as wild bees, which helps boost pollination services in the field.
Habitat-enhancing land management strategies for agrivoltaics
In my dissertation (9), I simulated the impact of five habitat-enhancing land management strategies on ecosystem services within agrivoltaic systems. This involved incrementally introducing grassland flowering strips, hedgerows, and trees in an agricultural field. The study employed ecosystem services software developed by Stanford University and geospatial modelling techniques (9). The strategies were informed by inputs from solar and agricultural experts, Germany’s agrivoltaic standard (11), and the EU's new Common Agricultural Policy (CAP) which encourages farmers to dedicate a small portion of their land to biodiversity measures in exchange for subsidies.
One important finding of the study was that pollination services by wild bees increased exponentially when introducing habitat-enhancing land management approaches. For example, surrounding the field with hedges and introducing narrow flowering strips on either side increased pollination services by 30% while still allowing agricultural combines to manoeuvre effectively. This scaled to 80% if dedicating 20% of the land to habitat-enhancing measures.
Introducing fruit plantations represents a promising opportunity to enrich biodiversity and boost farm income
An innovative proposal from the study is to combine annual crop (12) cultivation with horticulture such as fruit plantations. Horticulture not only yields higher financial returns—up to five times more than traditional crops—but also offers richer resources for bees and other pollinators. Adopting just 22% of farm space for horticulture, alongside grasslands and hedges, elevated pollination services by up to 87%. A promising opportunity to enrich biodiversity, boost farm income and sustain farming practices for the future!
An opportunity to bring together solar developers, farmers, landowners and conservationists
Agrivoltaics could take a pioneering role in introducing habitat-enhancing measures to agricultural cultivation while scaling solar energy production and minimising land use conflicts. Typically, around 10% of the land is lost for agricultural production due to the solar PV mounting system which could instead be utilised to create conservation habitat. Moreover, hedges are commonly used as ecological compensation measures for renewable energy projects to effectively conceal the visual impact of the solar site. Finally, by providing diversified income opportunities from solar power, agrivoltaics empowers farmers to allocate additional resources towards biodiversity conservation measures. The creation of frontrunner solar landscapes with trees, hedgerows and wildflower fields moreover enhances the site’s visual appeal, promoting public acceptance of solar power at the local scale. The approach also has the potential to foster collaborative relationships among solar developers, farmers, landowners, and conservationists. Such alliances offer invaluable perspectives for the EU biodiversity strategy, representing a noteworthy step toward harmonizing farming, nature conservation, and renewable energy.
References
- A. Barron-Gafford et al., "Agrivoltaics provide mutual benefits across the food–energy–water nexus in drylands," Nature Sustainability, Article vol. 2, no. 9, pp. 848-855, 2019, doi: 10.1038/s41893-019-0364-5
- BMWK, "Photovoltaik-Strategie, Handlungsfelder und Maßnahmen für einen beschleunigten Ausbau der Photovoltaik," 2023
- WWF, "Risiko Dürre - Der weltweite Durst nach Wasser in Zeiten der Klimakrise (Drought risk - The global thirst for water in times of climate crisis)," 2019
- Zulian, J. Maes, and M. L. Paracchini, "Linking land cover data and crop yields for mapping and assessment of pollination services in Europe," Land, Article vol. 2, no. 3, pp. 472-492, 2013, doi: 10.3390/land2030472
- Sánchez-Bayo and K. A. G. Wyckhuys, "Worldwide decline of the entomofauna: A review of its drivers," Biological Conservation, Review vol. 232, pp. 8-27, 2019, doi: 10.1016/j.biocon.2019.01.020
- Kosior et al., "The decline of the bumble bees and cuckoo bees (Hymenoptera: Apidae: Bombini) of Western and Central Europe," ORYX, Article vol. 41, no. 1, pp. 79-88, 2007, doi: 10.1017/S0030605307001597.
- Marrou, L. Guilioni, L. Dufour, C. Dupraz, and J. Wery, "Microclimate under agrivoltaic systems: Is crop growth rate affected in the partial shade of solar panels?," Agricultural and Forest Meteorology, Article vol. 177, pp. 117-132, 2013, doi: 10.1016/j.agrformet.2013.04.012
- H. Adeh, J. S. Selker, and C. W. Higgins, "Remarkable agrivoltaic influence on soil moisture, micrometeorology and water-use efficiency," PLoS ONE, Article vol. 13, no. 11, 2018, Art no. e0203256, doi: 10.1371/journal.pone.0203256
- Ludzuweit A., Quantifying the Impact of Habitat-Enhancing Strategies on the Ecosystem Services in Agrivoltaic Systems, A case study focusing on North-Eastern Germany, Masters dissertation 2023, University of Edinburgh, Carbon Management. The software employed was INVEST - Integrated Valuation of Environmental Services and Trade-offs software in combination with the Geographic Information System QGIS
- Ecoystem Services are benefits that people obtain from ecosystems. These benefits can include provisioning services (such as food, water, and raw materials), regulating services (such as climate regulation, flood control, and water purification), cultural services (such as recreation, spiritual, and aesthetic benefits), and supporting services (such as nutrient cycling, soil formation, and habitat provision).
- The DIN-Spec 91434, capping agricultural land loss at 15%
- Annual crops are plants that grow, produce seeds, and die all in one year, requiring replanting each season, such as corn, wheat, and tomatoes.
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