In a recent study published in the journal Renewable Energy, researchers from the University of Cordoba explained the remedies for the struggles faced in agriculture by using solar energy, which is comparatively economical and environmentally friendly.
Researchers Juan Antonio Rodríguez, Maaike van de Loo, and Emilio Camacho from the University of Cordoba. Image Credit: University of Córdoba
Irrigation faces the challenge of becoming more sustainable, both environmentally and economically. In this context, it is suggested that the future of agriculture should pursue energy self-sufficiency. The Lower Guadalquivir Valley Irrigation Community, which spans about 19,000 hectares and employs over 2,000 irrigators, started generating its solar energy in 2019 when a 6-megawatt photovoltaic facility was installed.
This irrigation system is the largest in all of Spain. Because of this, it has become a pioneering and testing ground for the scientific community as they work to transition to an irrigation paradigm that is both economically and environmentally sustainable.
The most recent example is its close cooperation with the Hydraulics and Irrigation research group of the María de Maeztu Unit of Excellence in association with the Department of Agronomy (DAUCO) of the University of Cordoba. DAUCO has suggested various approaches to optimize the utilization of the solar energy it generates, avoid wastage, and lessen reliance on outside energy sources.
The study's researchers, Maaike van de Loo, Emilio Camacho, and Juan Antonio Rodríguez, clarify that while a secondary source is required to meet energy needs when solar energy is not being produced at night, for example, there is currently a surplus of about 50% generated by solar energy production over consumption.
Two potential remedies for this problem have been investigated. These would help to minimize the amount of energy lost and maximize its utilization.
The first suggests that producers adopt new behaviors, such as scheduling irrigation to occur during the day when solar energy is generated and refraining from doing so at night. The research team notes that this strategy is a paradigm shift because, historically, the Lower Valley Community chose to irrigate at night. After all, it offered lower energy costs and warmer temperatures, which lower water evaporation levels.
Irrigators should alter their routines, though, because of the reduction in energy costs brought about by the construction of the photovoltaic plant and the growth of drip irrigation, which can cut water consumption by up to 60% when compared to other conventional methods by allowing for more precise application and minimizing losses.
The research team suggests giving up on-demand irrigation, which requires water to be available 24 hours a day, and focusing its use during the 8 to 12-hour window of daylight. This would greatly boost the amount of photovoltaic energy that is readily available above 90%.
The researchers make clear that because solar energy is dependent on weather and environmental factors, even if this strategy is put into practice, there will always need to be a backup energy source. However, the approach would greatly lessen reliance on outside sources and help create a more environmentally and economically viable irrigation plan in an area like Andalusia, which receives more than 3,000 hours of sunshine annually.
The second scenario is economic and involves selling surplus energy, a practice that the Lower Valley Community has been engaged in since the plant's installation. However, cheaper costs have resulted from increased solar energy output in Europe and the United States, decreasing its profitability.
The study concludes that while solar energy is a significant resource, there is currently no technology that ensures 100% usage of it. However, the researchers are optimistic that their work and the Lower Valley Irrigation Community's experience will open the door for future irrigation systems that can fully utilize the region's potential while balancing environmental preservation and financial gain.
Journal Reference:
van de Loo, M., et al. (2024) Defining the optimization strategy for solar energy use in large water distribution networks: a case study from the Valle Inferior irrigation system, Spain. Renewable Energy. doi.org/10.1016/j.renene.2024.120610.