Clean energy may stress global water resources. Scientists have found that climate mitigation efforts in the energy system could lead to increasing pressure on water resources.
In this latest study, the researchers aimed to systematically pinpoint the drivers of water demand in the energy system, examining 41 scenarios for the future energy system that are compatible with limiting future climate change to below the 2-degree Celsius target. This is particularly important in the face of lowering greenhouse gas emissions while still preventing water scarcity.
The global energy sector currently accounts for about 15 percent of global water use. According to the study, global water use of energy could increase by more than 600 percent by 2100, relative to the base year of 2000. Most of this water usage comes from thermoelectric power plants, which rely on water for cooling.
The use of water isn't the only concern, either. When water is used for cooling, it is then released back into the environment at a higher temperature. This is a problem known as thermal pollution, which can affect aquatic organisms. Thermals pollution could greatly increase in the future unless measures are taken to reduce pollution through mitigation technologies.
"While there are alternative possible energy transition pathways which would allow us to limit global warming to 2 degrees Celsius, many of these could lead to unsustainable long-term water use," said Oliver Fricko, the lead author of the new study and IIASA researcher. "Depending on the energy pathway chosen, the resulting water use by the energy sector would lead to water allocation conflicts with other sectors such as agriculture or domestic use, resulting in local shortages."
The study highlights the importance of energy efficiency. This is especially true for developing countries where electricity demand is set to increase rapidly. In addition, it shows the importance of an integrated analysis for understanding interlinked global challenges related to water, climate, and energy.
"Our findings have major implications for the way how climate change mitigation strategies should be designed," said Keywan Riahi, Director of the Energy Program at IIASA. "Energy partners need to put more emphasis on the local water impacts, since they may limit policy choices. Ultimately we need integrated strategies, which maximize synergies and avoid trade-offs between the water and climate change and other energy-related objectives."
