Carbon capture and sequestration in power generation: review of impacts and opportunities for water sustainability

摘要

This article reviews the use of carbon capture and sequestration (CCS) as a viable mitigation strategy for reducing greenhouse gas (GHG) emissions in fossil-fuel power plants and discusses the impacts on the sustainability of freshwater resources. While CCS technology can significantly mitigate anthropogenic GHG emissions, CCS installations are expected to impose new water stresses due to additional water requirements for chemical and physical processes to capture and separate CO~(2). In addition to these processes, the parasitic loads imposed by carbon capture on power plants will reduce their efficiency and thus require more water for cooling the plant. Groundwater contamination due to CO~(2)leakage during geologic sequestration is an additional concern when adapting CCS into power plants. Imposing such constraints on the quantity and quality of freshwater resources will influence decisions on the types of energy facilities and threaten the sustainability of water systems. A review of recent studies highlights three main challenges that would impact water sustainability due to CCS installation: (1) water requirements needed for different stages of CCS, (2) changes in groundwater quality due to carbon leakage into geologic formations, and (3) opportunities for using desalinated brine from saline sequestration aquifers to provide new freshwater sources and offset the CCS-induced water stresses. This article also reviews availability and gaps in datasets and simulation tools that are necessary for an improved CCS analysis. Illustrative analyses from two US states, Louisiana and Arizona, are presented to examine the possible consequences of introducing CCS technologies into existing power plants. A basin-scale, water stress framework is applied to estimate the added stresses on freshwater resources due to CCS installations. The scenario-based illustrative examples indicate the need for a full analysis of the inter-relationship between implementing different CCS technologies in the electric generation sector and the water system. Such analyses can be examined in future studies via an integrated energy-water nexus approach. Furthermore, the current article highlights the need for integrating the environmental, economic, and societal aspects of CCS deployment into future assessment of the viability of CCS operations and how to make water systems less vulnerable to CCS impacts.