Modelling Agrivoltaics in a climate perspective for water-energy-food nexus analysis

Renewable energies (REs) are increasingly important in addressing the challenge of climate change. Their development and widespread use can significantly reduce greenhouse gas emissions from fossil fuels and help mitigate the effects of climate change. To achieve a "net-zero" carbon economy, the transition to a RE system must occur alongside a profound transformation of the agri-food sector. Agrivoltaics (AVs) offers an opportunity to achieve both of these goals simultaneously. AVs provides clean energy and it is an important tool for realizing a sustainable and circular food economy in rural and farming communities. Additionally, by placing photovoltaic (PV) panels over crop fields, AVs can avoid the competition between solar energy and agriculture for land-use. This can also help to mitigate the impact of climate change on crop productivity, which is expected to be negatively affected by a warmer and drier future climate.
In our study, we developed a large-scale sub-grid AVs model to explore the inter-links between climate, the AVs system, and crops. This model enables a comprehensive evaluation of the effectiveness and efficiency of an AVs configuration within the context of the climate-water-energy-food nexus. Our approach involves coupling a PV model with the soil-vegetation-atmosphere-transfer model ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) to construct the AVs module. The PV layer simulates the effects of PV panels, altering solar radiation and wind speed taken from atmospheric forcings. Subsequently, these altered variables, along with other key atmospheric variables like air temperature and precipitation required by ORCHIDEE, are used as inputs to the hydro-vegetation layer. Leveraging ORCHIDEE capability to quantify terrestrial water and energy balances at the land surface, this integration allows for a comprehensive simulation of crop ecosystem behavior within an AVs system. Net Primary Production (NPP), Water Use Efficiency (WUE), and PV power potential (PV_pot) are finally computed as ultimate outputs of our model, representing key indicators for the water-energy-food nexus. Focusing on the Iberian Peninsula and the Netherlands, we apply our model to assess three AVs configurations (fix-tilted array, sun tracking, sun antitracking) across three specific years (2015, 2018, 2020) for two types of crops. Specifically, we compare the performance of different configurations among themselves and against the situation without AVs systems to analyze different behaviors depending on climate conditions, crop type, and location and to explore the potential benefits of the AVs systems.