Measuring Technical Efficiency, Environmental Efficiency and Energy Efficiency in Desalination Plant by Data Envelopment Analysis

This study is carried out to measure the technical and environmental efficiencies of reverse osmosis desalination plant by Data Envelopment Analysis (DAE) approach in the South Pars Special Economic Zone during the nine years from 2007 to 2016. The energy efficiency is estimated by Total Factor Energy Efficiency Index. The results reveal that the technical efficiency of the plant throughout the years in operation averaged out at 90.8% and 98.4%, based upon the assumption of constant and variable returns to scale, respectively. Scale inefficiency proved to be the most decisive factor leading to technical efficiency under the assumption of CRS, implying the relative neglect of scale efficient production in this unit. Eco-efficiency is assessed by adding undesirable outputs to this model. The highest level of eco-efficiency (99.9%) was observed in the year 2008, while the year 2016 demonstrated the lowest figure in this regard, i.e., 76.8%. The average eco-efficiency of the desalination plant in question during the whole years in operation amounted to 90%. Finally, using the Total Factor Energy Efficiency Index the average of energy efficiency of the desalination plant is estimated at 91%. The results showed that the temperature is the most important factor in energy efficiency, whose increase would result in significant energy efficiency decrease.