Harmonizing Photovoltaic Systems And Surrounding Agriculture

Pollination is a fundamental process of nature in both wild and agricultural ecosystems that is very critical for food production, human livelihood, and cultural values [1]. Bees and other pollinators are responsible for crop production, and more than 70 percent of all flowering plants are pollinated with the help of insects and other animals.

However, pollinators have been exposed to growing pressures from climate change, loss and fragmentation of (semi-)natural habitats, monocultures, increasing use of pesticides, the spread of pathogens, and the introduction of invasive alien species [1, 2]. Therefore, pollinators around the world are in trouble with important ecological and economic consequences.

Recently, specific European policies aimed to decarbonize economic growth and to encourage renewable energy development (Directive 2001/77/CE), have favored the conversion of agricultural crops to photovoltaic (PV) systems. The generation of electricity through PV systems can contribute to the reduction of greenhouse gas emissions with significant environmental benefits in comparison to the conventional (fossil) energy production. However, the realization of ground-based PV systems can also produce several impacts on landscapes and biodiversity in terms of land degradation, loss of cultivable land, and habitat loss.

Therefore, it is very important to propose new approaches able to harmonize energy production, agriculture, and the safeguard of ecological processes that underpin human well-being, creating a strong synergism between economic and institutional players. In particular [3] it is suggested that a new approach in designing and assessing large-scale PV systems may help to reduce environmental impacts and offer new possibilities for ecosystem services.

In a study carried out in Salento, South Italy, in collaboration between Global Solar Fund Group (an industrial firm founded in 2008 which operates in the photovoltaic energy sector), authors have advanced the idea that PV can be evolved in Green Infrastructures (“photo-ecological urban gardens”) where economic, ecological, and social aspects can coexist without causing trade-off among them.

The solar panels analyzed in this study were surrounded by invasive herbaceous vegetation with no valuable floral elements; the flora was ruderal, nitrophilous, requiring frequent removal (at a cost of about € 3,300/MWp) to reduce the risk of fires and prevent shade on the panels. For this reason, the basic idea was to replace the invasive vegetation between and around the panels with autochthonous melliferous and medicinal flora. These selected plants will not require specific professional skills; they will grow autonomously, with no need for annual maintenance to ensure growth.

For the arboreal and shrub plants, irrigation will be necessary at the beginning in order to get through the hottest periods, with a maximum of six operations during the first two years in the period May-September. In this way, regular gardeners can be employed, making use of local botanical gardens in the start-up phase. The choice of melliferous plants aims to produce honey and other honey-related products like Royal jelly, honeydew that can have also a market appeal. Moreover, other economic activities related to crop production can be considered, like medicinal production.

The benefits for the PV companies are multiple. Besides the economic return on such cultivation, which is dependent on the management, the most important advantages are summarized as follows: avoid of mowing costs; reduction of the risk for fire; reduction of false alarm for the security laser fence.

Therefore, a new approach is developed to manage photovoltaic solar farms, shifting from “negative vegetation management,” aimed mainly at the elimination of invasive plants, to “active vegetation management,” useful for increasing company revenues and social and ecological benefits. This would create a harmony between energy production and territorial sustainability through actions that create positive feedbacks between business management of solar farms and the development of ecological processes in the territory.

These “new urban photo-ecological gardens” in agricultural landscapes, mainly characterized by monocultures, could represent a source of biodiversity improving the presence of vegetation with an important ecological role. They could support the network of nature at both the local scale: for bees and other local insects and animals that can use these plants as a habitat; and broad scale: for species of migratory birds that can find refuge in these new habitats.

These findings are described in the article entitled Planning ground based utility scale solar energy as Green Infrastructure to enhance ecosystem services, recently published in the journal Energy Policy. This work was conducted by Teodoro Semeraro from the University of Salento, Alessandro Pomes from Technital SpA, Cecilia Del Giudice and Danilo Negro from the Global Solar Fund, and Roberta Aretano from Apulian Regional Agency for the Environmental Prevention and Protection.

References:

1. Potts, S.G., Imperatriz-Fonseca, V., Ngo, H.T., Aizen, M.A., Biesmeijer, J.C., Breeze, T.D., Dicks, L.V., Garibaldi, L.A., Hill, R., Settele, J., Vanbergen A.J., 2016. Safeguarding pollinators and their values to human well-being. Nature. 540, 220–229.
2. Vanbergen, A.J. and the Insect Pollinators Initiative, 2013. Threats to an ecosystem service: pressures on pollinators. Frontiers in Ecology and the Environment. 11(5), 251–259.
3. Scognamillo, A., 2016. ‘Photovoltaic landscapes’: Design and assessment. A critical review for a new transdisciplinary design vision. Renewable and Sustainable Energy Reviews. 55, 629–661.