Arlington, Virginia — Installing carbon capture and sequestration technology at existing large coal-fired power plants around the world could leave many of them short of water at least for part of the year, a new scientific study has found.
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Around 43%, or 830 GW, of the nearly 1,100 coal-fired plants examined in the study would experience water scarcity for at least one month per year if they were retrofitted with carbon capture and sequestration, or CCS, scientists from the University of California Berkeley said in a May 4 article published in the journal Nature Sustainability. The scientists also found that 32%, 625 GW, of those plants could see water shortages for five months or longer if they installed CCS technology.
Scientists and companies that have set emissions-reduction targets have said that CCS will be a key part of tackling climate change, particularly to achieve global net-zero emissions by around 2050.
The new scientific article asserted that "the twin costs of mitigating climate change and competing for water resources are vexing factors in managing energy systems." The scientists recommend that "the water requirements of CCS technologies should be taken into account when evaluating future CCS scenarios because it is crucial to mitigate emissions from the energy sector without compromising on the sustainable use of water resources."
CCS would increase water usage at coal-fired power plants in two ways, the UC Berkeley scientists wrote. First, CCS itself imposes parasitic power demands on existing plants, which inherently increases the amount of water the plant consumes and reduces the plant's efficiency. Second, the CCS process requires additional water. For example, the one proven and commercially available technology that achieves carbon absorption with amine solvents would nearly double a coal-fired plant's water combustion intensity.
MOST AT RISK ARE IN CHINA
Of the plants that could face water risk for at least five months of the year, the study said 56% are in China, 15% in India and 11% in the US. Coal plants that would not face water scarcity year-round are located in the Great Lakes region of the US, in Europe, Russia, and southern China. In addition, plants located along ocean coastlines where they could opt to use seawater as a cooling medium but do not currently would not be affected.
During a May 6 webinar hosted by the United States Energy Association, Fred Eames, an energy lobbyist and partner at Hunton Andrews Kurth, talked about the study. He also suggested that any time a new or retrofitted project is expected to use more water, particularly in the drought-prone areas of the Western US, the issue of water resource allocation will always have to be addressed.
To eliminate the possibility of including plants in the study that are older and likely to be retired rather than retrofitted with CCS, the scientists assessed the potential monthly water withdrawals and consumption levels associated with adding CCS to the 1,093 coal plants globally that have a capacity of 100 MW or more and began operating after 2000. The modeling was based on the long-term monthly average available water from 2011 through 2015 and also accounted for annual variability in water resources.
The scientists noted that water consumption can vary by up to 20% among coal plants depending on coal type, combustion technology, plant size and efficiency, and existing environmental control systems.