Organized within the framework of the European Sol2H2O project by the Chair of Renewable Energies at the University of Évora in collaboration with consortium partners—Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT, Spain), Instituto Tecnológico de Canarias (ITC, Spain), and the University of Palermo (UNIPA, Italy)—it culminated several national events held in Portugal, Spain, and Italy.
Participation in the event was significant, with over 40 participants from public and private entities, including various companies in the sector, who had the opportunity to present technological innovation projects in wastewater treatment, water production through desalination, and valorization of desalination brines.
During the event, the results of the national sessions were presented, where the 6-3-5 brainstorming methodology was used to answer five pre-defined questions. These focused on the challenges and potential solutions for implementing water treatment processes for the production of Reuse Water (ApR), particularly for irrigation; the successful implementation of Zero Liquid Discharge (ZLD) solutions in the market; and water storage as a solution for energy storage in large-scale renewable energy systems.
These national sessions allowed the identification of common challenges and solutions among Portugal, Spain, and Italy, emphasizing their cross-cutting nature.
Regarding ApR production, economic issues related to technology costs, social issues regarding public and farmer perception of ApR usage risk, and administrative and regulatory barriers were highlighted. As a solution, improved communication and revision of the legal framework (with stakeholder involvement) were suggested.
Regarding ZLD solutions, issues related to their economic viability at a large scale were discussed, focusing on energy needs and raising awareness of brine as a resource. Investment in R&D, promotion of the circular economy, and market studies for recovered brine products were suggested.
Additionally, the relevance of water management as an element in electricity management was highlighted, including its production, geo-strategic storage, and distribution.
The discussion, moderated by the Sol2H2O project coordinator, Dr. Pedro Horta, was highly interactive, revealing participants’ interest and knowledge on these topics. Barriers were identified, and suggestions were presented regarding the optimization of desalination processes and plant design, including the integration of renewable energy sources and brine valorization processes; the need for detailed economic studies to assess the potential market implementation of brine valorization technologies; and the need to implement an ApR distribution network, allowing more effective reuse of treated wastewater, as well as more efficient dissemination of R&D results related to ApR quality for irrigation.
The event reaffirmed the importance of continuous collaboration between public, private, and academic entities, ensuring that the management of the Water-Energy nexus in Europe is marked by innovation, resilience, and sustainability.