Using solar energy for irrigation in large water distribution networks: A benchmark study about six irrigation systems in the south of Spain

• Benchmark study on solar energy in large irrigation systems in southern Spain. • Solar energy covers 40–57 % of total energy, yet costs rose by 15–302 % in 2022. • Declining profits and regulations limit selling excess solar energy. • Storing solar energy is key to reducing reliance on fluctuating energy markets. • Optimized solar use boosts system efficiency, stability, and economic viability. Increased energy requirements and rising energy costs have led to a growing adoption of solar energy in large irrigation systems, especially in southern Spain. This benchmark study evaluates six large-scale irrigation systems, assessing solar energy integration and its interplay with agricultural water management practices. Results indicate that while the ratio of solar energy to total energy consumption ranges from 0.40 to 0.57 across systems with large solar plants of several MWs, full solar energy utilization remains constrained due to the 24-h on-demand irrigation schedules, necessitating reliance on conventional energy during non-solar hours. Despite reductions in energy consumption, in most systems energy costs rose significantly, with increases between 15 % and 302 %, driven by global market fluctuations. Selling excess solar energy presents a potential economic relief, yet regulatory restrictions often inhibit this practice. Even when feasible, profitability is challenged by dynamic energy prices. The study highlights the need for innovative solutions, including energy storage technologies like batteries and pumped hydropower, and systemic scheduling adjustments to enhance solar energy use. Broader adoption of technologies such as floating solar panels and certifications like ECO20 could further support energy sovereignty and sustainability. This research underscores the challenges and opportunities in optimizing solar energy for irrigation, offering valuable insights for system managers and policymakers navigating the transition to renewable energy in agriculture.