The impact of CO2 capture on water requirements of power plants

Addition of a CO2 capture system to an existing power station has some impact on water consumption. CO2 capture systems require additional water for cooling and process make-up. During the past decade, a number of relevant studies have been published that estimate the increase in water use when a capture system is added to Pulverized Coal (PC), Natural Gas Combined Cycle (NGCC) and Integrated Gasifier Combined Cycle (IGCC) power generation facilities. This paper provides a comprehensive analysis of these estimates available for post-, oxy- and pre-combustion CO2 capture systems, making it possible to compare different technologies, and to better understand how adding a CO2 capture system on a power plant impacts the volume of water withdrawn and consumed. The results of this study serve to dispel myths about the use of water in CCS systems. Specifically, they challenge the generic statement that CCS systems will double water consumption, which is often reported in papers and articles. Water use estimates cannot be generalized and are very dependent on the power plant type, the CO2 capture technology and the cooling system used. The estimates indicate that for power plants served by wet-recirculating systems, the increase in actual water consumed varies approximately from 20 to 60 per cent, depending on the capture technology. For once through cooling systems the increase can be negligible, or even be negative when water recovery options are implemented.(c) 2017 The Authors. Published by Elsevier Ltd.