Life-cycle assessment of thermal desalination: Environmental perspective on a vital option for some countries

A shortage of freshwater is one of the leading factors restricting sustainable global development. Desalination has evolved to overcome water shortages in many regions since the mid-20th century, especially in North Africa, the Middle East, some states of the United States, and Mediterranean countries. In particular, Middle Eastern countries have established desalination facilities that produce approximately half of the globally desalinated water to secure the future of humanity, and a large percentage of this water comes from thermal desalination. The energy intensive nature of thermal desalination creates significant negative impacts on the environment, which has been poorly understood in many of these countries. Therefore, to quantify the environmental impact in a case study, we selected a small country of the Arabian Gulf, Qatar, which has a total annual desalination capacity of approximately 500 million m3 of which 68% is being produced by multi-stage flash (MSF) thermal desalination. Life cycle assessment (LCA) was employed to quantify the impacts of two different MSF configurations with varying gained output ratios (GORs). Environmental load analysis showed that the plant with the low GOR released a higher amount of CO2 (12. 6 kg) to produce 1 m3 of water while the modified plant with the high GOR released less CO2 (7. 32 kg) per m3 of water. This comprehensive quantitative analysis has a significant regional impact because it has the potential to act as baseline for more sustainable water systems in areas that are highly dependent on MSF desalination for water security.