Carbon dioxide emissions elimination for reverse osmosis desalination units of remote islands via photovoltaic and battery solution. The case of Karpathos Island

Recently, the imperative water demand problem of small islands in the South-East Mediterranean area is being faced with the development and operation of new reverse osmosis (RO) desalination plants at high operational and environmental cost. One of the most serious RO desalination unit’s problems is their high-energy demand. This water demand coincides with the electricity demand, both peaked during the summer imposing the existing local electrical power stations to operate near their upper limit. For the radical solution of all these critical problems, the water demand profile should systematically be measured along with the existing local water supply potential. Accordingly, the corresponding water production-related electricity consumption is measured. Using the above-described parameters along with the available solar irradiance, the opportunity to support the necessary desalination plants with appropriate photovoltaic (PV) installations is examined. The current work investigates the sizing and the operation of appropriate PV plants used to provide the necessary electricity demand of existing or new RO desalination plants replacing the operation of diesel-based thermal power stations. For the safe and undisturbed operation of the desalination plants, the introduction of small batteries is also examined. The proposed parametric analysis, using several combinations of PV park peak power and battery capacity values, attempts to maximize the clean energy autonomy of a representative desalination plant, minimizing the fossil fuels consumption and the corresponding carbon dioxide emissions, at rational investment cost. The developed numerical algorithm is applied for the Island of Karpathos using real world data and providing very interesting results.