The Puerto Rico Aqueduct and Sewer Authority (AAA) told legislators during a public hearing at the House of Representatives on Thursday that, under current conditions, large-scale desalination is not technically or economically justifiable as a solution for future water supply crises, though the technology should continue to be evaluated as a strategic resource. As part of an alternatives analysis for the Carraízo reservoir, AAA studied building a 6-million-gallon-per-day (MGD) reverse osmosis plant but discarded the plan due to construction and energy costs and environmental impact.
A similar option was considered for the new Salinas filtration plant, whose preliminary engineering study found the alternative had "a prohibitive cost" in both construction and operation/maintenance; the bid for that facility’s construction is scheduled for April 2027. Engineer Ann Ventura, AAA’s deputy director of Infrastructure, said desalination offers resilience during droughts since seawater doesn’t depend on rainfall, but it creates heavy dependence on electricity instead.
AAA noted seawater reverse osmosis, using high-pressure pumps and membranes, is the most promising technology for the island but poses major energy and environmental challenges. As an example, California’s 50 MGD Carlsbad plant required over $1 billion in initial investment and consumes 274 million kWh annually. Thomas and St. [Croix] islands, though details are cut off.