Sandia National Laboratories (SNL) and the National Energy Technology Laboratory (NETL) are conducting a study to assess the synergistic use of underground saline formations as both a storage site for captured carbon dioxide (CO₂) – carbon sequestration –  and as a source of water to support the operation of thermoelectric power plants.  In the future, fossil-fueled thermoelectric power plants may be required to control CO₂ emissions as a means to mitigate global warming.  In one control option currently under development, the captured CO₂ would be injected into a deep saline formation for permanent sequestration.  This might require the continuous removal of some quantity of saline water – also known as produced water – in order to relieve pressure within the formation.  The produced water provides an opportunity for beneficial use as an alternative to freshwater make-up for the power plant cooling water and flue gas desulfurization (FGD) systems.  However, the produced water is likely to contain chemical contaminants that require treatment before it can be utilized.

Sandia is using its geochemistry and desalination technical expertise to assess the changes in water quality from CO₂ injection into saline formations and determining the treatment methods and costs needed to beneficially use the produced water in power plants or for other uses. The data collected will be used in conjunction with information from NETL’s Office of Systems Analysis and Planning (OSAP) to conduct a systems-level evaluation of the regional challenges and opportunities to optimize power plant processes such as CO₂ sequestration and waste heat recovery to improve water resource utilization while reducing system costs. The efforts will include water geochemistry research, cost analysis of the produced water treatment needs, and systems analysis of regional benefits and opportunities.