Y. Lin, Z. Zhou, S-Y Pan, S. Snyder
Argonne National Laboratory,
Keywords: Water energy Nexus, Desalination
Summary:Freshwater stress and scarcity is one of the most challenging emerging issues due to climate change, rapid population growth, urbanization, and improved standards of living. Desalination of seawater or impaired water, such as brackish water and plant (process) water, could be a resource-efficient solution. A major part of energy-water nexus concerns the energy efficiency and energy consumption for supplying and treating water. One of the emerging industrial impacted is the thermoelectric power plants that use the single largest source of water withdrawal in the United States. It withdraws large quantities of water (~196 G gal/day, 40% total water withdraws in US) for cooling and dissipates tremendous amounts of primary energy. Ensuring the recycling of water from cooling towers and the use of reclaimed water (municipal waste water, brackish water and recycled) to replace the surface water withdraws is one of the strategies to reduce water withdrawal. Energy efficiency of treating reclaimed water thus will play a crucial role in shifting away from the use of surface water sources. In this presentation, a water-energy interdependency network (WEIN) model is proposed to directly correlate the quantity and quality of energy and water during the development of the most fit-to-use water treatment technologies in a chain of water use entities, to minimize associated cost or water/energy use. A simpler but commonly existing relationship between water use entities: chain model (tandem model), is setup where entities are connected as a tandem queue as upstream and downstream. Using the WEIN, water use entities can be connected in any way and any direction by a network model. A water treatment technologies database including process performance of energy consumption, purification ratio, processing rate and process economics is used to establish different decision model. Given the degree of information sharing and coordination between entities, the decision models of “no coordination” and full coordination are compared. For coordinated network, the objective is to optimize the energy use/cost saving for all related entities by selecting the most appropriated water treatment technologies and treatment schedule/strategies. For entities without coordination with any others, its decision is optimized individually given whatever water it receives and complies.