Solar photovoltaics integration for restoring arid land (SPIRAL)
As the most affordable option for electricity generation, solar energy plays a significant role in the global energy transition. According to the annual report by IEA PVPS, the installed capacity of solar photovoltaic (PV) systems in 2021 witnessed a remarkable growth of 22% compared to 2020. This expansion contributed approximately 5% to the global electricity demand. Solar PV can be deployed on various surfaces, ranging from rooftops and facades in the built environment, to different types of water bodies, and vehicles, and also play an increasingly important role at arable and arid lands. Utility-scale PV systems are usually ground-based and space-intensive, which causes tension due to competition for scarce land between the production of energy, food, and other ecosystem services. Recent practices of combining PV systems with crop cultivation in agricultural areas (aka “Agrivoltaics”) can improve overall land-use efficiency, but a trade-off between PV performance and crop yields limits effectiveness due to light competition between vegetation and solar panels, especially for less shade-tolerant crops. However, this shading effect can also provide benefits, especially in arid regions (which make up 41% of the global land areas, for the following reasons.
- By reducing evaporation, solar PV can create a more suitable microclimate for vegetation growth, which in turn can facilitate the build-up of organic matter in the soil and restore soil fertility.
- An effective solar mounting design can reduce the impact of wind erosion by blocking wind, reduce wind-borne dust and sand, and facilitate optimal distribution of rainfall through the optimization of panel title angle for the land. The root system of the vegetation can further deter soil erosion and contribute to soil conservation. Consequently, this synergistic effect could promote carbon sequestration in the soil and biomass, effectively establishing a carbon sink.
The co-benefits of PV applications extend beyond the mere supply of renewable energy. They encompass the reversal of desertification, increased vegetation growth production, and the creation of local employment opportunities. However, these additional benefits have not been sufficiently quantified. At present, lack of investments due to a lack of knowledge of co-benefits is a key restraint in the implementation of large PV systems with multiple co-benefits. Alleviating this knowledge gap could significantly contribute to an enhanced understanding of PV technologies, the development of appropriate legislation, improved informed decision-making, and advanced solar PV technical designs, leading to greater solar PV annual yield, in combination with improved ecological and biodiversity benefits.
The objectives of this project are as follows;
- Understanding the ecological co-benefits and potential challenges associated with a multifunctional land-use approach (e.g., vegetation production, soil fertility, carbon stocks) that combines energy production from solar PV deployment with the restoration of arid land
- Identification of suitable crops for different climates within the proposed multifunctional land-use framework.
- conducting a feasibility study and develop site-specific recommendations for optimized PV system deployment considering both ecological benefits and energy yield as two main objectives.