Water is a fixed resource with competing demands and increase uncertainty. There is an inextricable link between water and energy, as thermoelectric power generation accounts for 40% of freshwater withdrawals and 3% of freshwater consumption in the United States. Check out NETL’s recently published Water Brief for a more detailed discussion on water demands and consumption throughout the contingent US. Data utilized in the Water Brief was compiled by Sandia National Labs. NETL also works with Argonne National Lab to develop the AWARE Model examining water stress in the United States.
Water Management Challenges:
The Water Management program addresses these competing water needs and challenges, through a series of dynamic, complex models and analyses that are essential in informing and deciding priority technology R&D initiatives.
The program encompasses the need to minimize any potential impacts of power plant operations on water quality and availability. Analyzing and exploring plant efficiency opportunities can reduce the amount of water required for fossil energy operations.
NETL utilizes the Integrated Environmental Control Model (IECM) to provide systematic estimates of performance, emissions, costs, and uncertainties for a wide variety of fossil fuel-fired power generation systems. Most recently the IECM was used to assess impacts on regional water use and costs of switching from wet cooling tower systems to dry cooling systems in arid regions.
The program leads a critical, national effort directed at removing barriers to sustainable, efficient, water and energy use; developing technology solutions; and enhancing the understanding of the intimate relationship between energy and water resources.
Increasing Water Efficiency and Reuse
With the complex link between water and energy, it is increasingly important to use water effectively through the power generation sector. This area aims to advance concepts for both new and existing plants to minimize water intake and use. Examining plant cycles and testing new efficient processes, not only can reduce water intake, but also lower overall operating costs. Through this method, water availability and water usage challenges are addressed.
Treatment of Alternative Sources of Water
Identifying, and treating alternative sources of water, such as brackish and effluent streams, offers opportunities for scientists to address energy-water system challenges. This area focuses on furthering technology to utilize alternative water resources that can span multiple facts of R&D, including considerations of capital costs, operating costs, and system integration. Through this method, water quality as a challenge is addressed directly. Moreover, effluent treatment challenges and the effluent limitation guidelines are also addressed partially by examining new technologies for monitoring and treating of intake and effluent water.
The complex relationship between energy and water is constantly developing. There are multiple components that impact the system can be modeled and analyzed to better inform decision-makers, and scientists alike. Through this branch of the portfolio, water availability and water usage challenges are addressed by predicting and addressing challenges that may not be currently addressed
Water System Technologies at the Plant
This diagram explains the movement of water throughout the plant and highlights key technologies where water efficiency can be improved. Consider this diagram like a mass balance; all the water that enters the plant must exit the plant as well in some form, whether it is in liquid or vapor form. The technologies illustrated here specifically apply to a coal power plant with wet flue gas desulfurization systems. However, these technologies also apply broadly to other energy systems as well as industrial applications. Water is a vital ingredient to thermoelectric power generation, but some plants utilize dry or hybrid cooling to minimize or eliminate water usage in water-stress or water-constrained regions. In regions where water availability is not an issue, the diagram above depicts how water would flow in, out, and throughout the plant and be utilized in several systems such as in the condenser and boiler. Note that even though the blue arrows refer to water entering the plant and green arrows refer to water exiting the plant, much of this water is reused throughout the plant to limit the amount of water taken from the source. This limits environmental impact locally.