Renewable energy technologies, in particular concentrating solar power (CSP), are becoming more and more interesting for powering water desalination system. Moving from a European Community funded project called MATS, Multipurpose Applications by Thermodynamics Solar, which is in an advanced phase of detailed engineering, the authors have further developed an alternative scheme by a proper integration of CSP with multi-effect distillation (MED) and reverse osmoses (RO) desalination processes. According to the proposed scheme MED is powered by the low temperature exhaust steam delivered from the back pressure steam turbine while the RO is powered by the electricity produced by the same steam turbine in addition to that generated by a conventional gas turbine integrated as a thermal backup system. The effective match of the alternative solar thermal and electricity into such hybrid power-desalination scheme is discussed in details. An economical analysis together with a developed comprehensive model is provided where power availability, water production rates and environmental benefits have been implemented. Desalination using the CSP system through such hybrid integration allows also for a continuous operation and can be an effective way to lower the total water production costs not only for large-scale plants.