Renewable energy desalination plants for the Greek islands — technical and economic considerations

For the majority of the Greek islands, water resources are quite restricted, limiting the economic development of the local societies. To face increased potable water requirements, more than 2,500,000 m3 of clean water is transferred annually to these islands at a cost approaching the value of 7 i/m3. On the other hand, the final cost of the locally produced water from renewable energy sources (RES) based desalination plants is expected to be quite lower than this value. The main purpose of the present study is to examine the economic viability of several representative desalination plant configurations based on the available renewable energy sources using an integrated cost-benefit analysis. In the proposed analysis all the cost parameters of the problem are taken into consideration, including the capital cost of the desalination plant, the annual maintenance and operation cost, the energy consumption cost, the local economy annual capital cost index and the corresponding inflation rate. The calculation results obtained definitely support the utilization of RES-based desalination plants as the most promising and sustainable method to satisfy the fresh, potable water demands of the small- to medium-sized Greek islands at a minimal cost, without disregarding the considerable environmental and macro-economic benefits.

An integrated cost-benefit analysis concerning the desalinated water production cost for remote islands, using RES and RO desalination techniques is presented. According to the proposed solution, the desalinated water production activity belongs to an integrated solution for the energy and clean water demand problem of an autonomous community. For this purpose, the solution obtained should guarantee the clean water sufficiency of the remote community at a rational production cost, definitely lower than the current water market price in the same region. According to the results obtained, concerning several typical configurations of the proposed solution, the resulting maximum water production cost is less than 2.5 i/m3 for medium-sizecapacity installations and inferior to 3.5 i/m3 in very small ones. These cost values are remarkably reduced with the increase of the unit’s service life, while there is a significant potentiality for additional cost reduction by careful maintenance and operation of the system and by appropriate energy management of the installation. Bear in mind that the electricity consumption cost of the desalination plant strongly influences the desalinated water production cost. In addition, the increase of the UF of the selected desalination plant decreases the corresponding water production cost considerably. Furthermore, the economic performance of the integrated system is improved when the energy demand of the desalination plant is covered by the surplus of the energy produced by the RES power station. It is therefore proved that the implementation of alternative water supply solutions, such as desalination plants integrated with appropriate RES technologies, can contribute significantly to a sustainable solution of the water shortage problem, as it is justified in the present work. Hence, the authors believe that the proposed solution, in addition to its significant sustainability features, is economically competitive to any other clean water production solution for the Greek islands, thus enabling the supply of local communities with an adequate amount of water at a minimal cost. Thus, by adopting the proposed analysis, it is possible to accelerate the economic development of the small societies of the Aegean Archipelago, improving — at the same time — the quality of life of the habitants.