Influence of climate change mitigation technology on global demands of water for electricity generation

Globally, electricity generation accounts for a large and potentially growing water demand, and as such is an important component to assessments of global and regional water scarcity. However, the current suite—as well as potential future suite—of thermoelectric generation technologies has a very wide range of water demand intensities, spanning two orders of magnitude. As such, the evolution of the generation mix is important for the future water demands of the sector. This study uses GCAM, an integrated assessment model, to analyze the global electric sector's water demands in three futures of climate change mitigation policy and two technology strategies. We find that despite five- to seven-fold expansion of the electric sector as a whole from 2005 to 2095, global electric sector water withdrawals remain relatively stable, due to the retirement of existing power plants with water-intensive once-through flow cooling systems. In the scenarios examined here, climate policies lead to the large-scale deployment of advanced, low-emissions technologies such as carbon dioxide capture and storage (CCS), concentrating solar power, and engineered geothermal systems. In particular, we find that the large-scale deployment of CCS technologies does not increase long-term water consumption from hydrocarbon-fueled power generation as compared with a no-policy scenario without CCS. Moreover, in sensitivity scenarios where low-emissions electricity technologies are required to use dry cooling systems, we find that the consequent additional costs and efficiency reductions do not limit the utility of these technologies in achieving cost-effective whole-system emissions mitigation.

► Electric sector water withdrawals remain stable to 2050 due to stock turnover.
► Electric sector water consumption increases to 2100 and depends on the generation mix.
► CO2 capture technologies do not increase water consumption compared to no-policy reference.
► The value of low-emissions technologies remains high even when they use dry cooling.