Energy efficiency and desalination in the Canary Islands

Faced with the challenge of meeting high water and energy demands with no conventional energy resources and a lack of potable water, the Canary Islands have been using desalination plants for nearly 50 years. The first desalination plant in Europe was installed in 1964 in Lanzarote. Today, desalination capacity in the islands stands at over 600,000 m3/d (covering 55% of water demand). Powering the plants consumes nearly 12% of total electricity demand at a cost of over 200 million Euros yearly. Though desalination continues to be the main way of meeting water demand, its major drawback is the strong dependence on conventional energy. The islands have always looked for reducing the energy consumption in desalination processes. This paper describes the relationship between energy and desalinated water and its evolution in the islands over the past 50 years, examining the trends in energy efficiency and the technological changes in the desalination systems, which also explains the predominance of reverse osmosis plants in the current scenario. A series of case studies describe various challenging desalination projects (including operating data) that have been installed in the Canary Islands.