dThe prospective success of sustainable development in the Canary Islands, an insular land, will be essentially determined by the interrelation between four basic fields: water, energy, economy and environment. Economical, conventional and renewable energy resources and the local situation of water demand establish that the Canary Islands constitute a significant meeting point for desalination and renewable energy technologies. This paper aims to quantify the unit cost of fresh water generated from a representative wind-powered seawater reverse osmosis system (WPRO) as well as the exergy efficiency of the process (second law of thermodynamics) by means of thermoeconomy. Backup from the grid to balance temporary wind fluctuations is assumed; however, the mean annual energy back-Lip is nil. Therefore the calculated unit cost of fresh water is determined exclusively by considering a wind-powered desalination system.