Water–CO2 trade-offs in electricity generation planning

Abstract

The amount of water required for electricity generation is expected to increase as CO2 emissions are reduced. A capacity expansion model of the Texas electricity grid in the USA demonstrates the trade-offs between CO2 emissions and water use in designing the power generation mix. Better understanding of the ‘water–energy nexus’ should help to coordinate mitigation and adaptation planning in the energy sector. In 2011, the state of Texas experienced the lowest annual rainfall on record1, with similar droughts affecting East Africa, China and Australia. Climate change is expected to further increase the likelihood and severity of future droughts2. Simultaneously, population and industrial growth increases demand for drought-stressed water resources3 and energy, including electricity. In the US, nearly half of water withdrawals are for electricity generation4, much of which comes from greenhouse gas emitting fossil fuel combustion. The result is a three-way tension among efforts to meet growing energy demands while reducing greenhouse gas emissions and water withdrawals, a critical issue within the so-called water–energy nexus. We focus on this interaction within the electric sector by using a generation expansion planning model to explore the trade-offs. We show that large reductions in CO2 emissions would probably increase water withdrawals for electricity generation in the absence of limits on water usage, and that simultaneous restriction of CO2 emissions and water withdrawals requires a different mix of energy technologies and higher costs than one would plan to reduce either CO2 or water alone.

Cite this article

Webster, M., Donohoo, P. & Palmintier, B. Water–CO₂ trade-offs in electricity generation planning. Nature Clim Change 3, 1029–1032 (2013). https://doi.org/10.1038/nclimate2032

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