(711a) Energy and CO2 emissions Intensity of Desalination Systems

As water scarcity, induced in part by growing populations and climate change, becomes more prominent in the U.S. and globally, there will be greater interest in exploring seawater desalination to produce drinking water. Reverse osmosis is the predominant technology for desalination in the U.S., while thermal desalination technologies are typically used in other regions of the world, particularly those with large fossil fuel resources. Ongoing research and development have made these technologies more efficient, but in many areas of the world desalination is still more energy intensive than utilizing traditional freshwater sources. Further, if desalination systems are to be an option for mitigating the impacts of climate change, it is imperative to consider its CO₂ implications.

This presentation will detail the energy and CO₂ footprints of desalination systems in use globally today as presented in available literature and public data sets. A review of existing literature has identified a lack of consistent boundaries when reporting on desalination systems. The lack of consistency hinders evaluations and comparisons of the energy and CO₂ intensities of desalination systems, technologies and processes. This presentation will employ a consistent boundary analysis framework for evaluating each of the key general desalination system stages and the whole system, thereby enabling energy and CO₂ comparisons across desalination options. Desalination systems in this presentation will include intake, pretreatment, the desalination process, posttreatment, and concentrate management/brine disposal. The summary will seek to inform the following information on currently deployed desalination systems globally: adoption rates (globally and regionally), applications (e.g., volume produced, level of treatment required), energy and CO₂ emissions intensity, water production, brine production, reported capital and operational cost ranges, environmental considerations and integration into the existing water and electric network. The focus of the presentation will be on the production of drinking water from the desalination of seawater, though the production of drinking water from brackish water will be considered as well.

The research presented here will be used as a basis to inform the development of an Energy-Water Bandwidth Study for Desalination Systems targeted for completion in early 2017. Developed by the U.S. Department of Energy, Energy Bandwidth studies serve as generalized guides for energy technology advancement opportunities and the energy savings opportunity from individual technologies and combinations of multiple technologies in a system. The Energy-Water Bandwidth Study for Desalination Systems will evaluate the energy and CO₂ impact and reduction potential from the adoption of several technologies and practices under several U.S uptake scenarios.