As the world works to reduce carbon emissions, scientists are developing new technologies that can turn carbon dioxide (CO₂) into valuable fuels.
These technologies could help cut greenhouse gases while creating low-carbon fuel for hard-to-electrify vehicles like airplanes, ships, and trains.
However, converting CO₂ into fuel requires a lot of energy and water, raising concerns about water use.
To address these concerns, researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory are exploring ways to convert CO₂ into fuel without straining water resources.
They have developed a tool called the CO2Rue WATER module, which helps assess and reduce the water impact of different CO₂ conversion technologies.
This tool is part of a larger effort by DOE's CO2 Reduction and Upgrading for e-Fuels Consortium (CO2Rue), which focuses on creating environmentally friendly fuels and chemicals while considering the environmental, economic, and social impacts of these technologies.
The CO2Rue WATER module allows scientists to measure how much water is needed to produce sustainable aviation fuel (SAF) and other e-fuels. It uses two main indices: the Water Availability Index (WAI) and the Water Stress Footprint (WSFP).
These indices help measure local water impacts and show how water use varies by region.
The module is currently being tested in four pilot states: California, Texas, Louisiana, and Iowa. Future versions will cover 28 states across the U.S.
A recent study using this tool found that SAF production affects water resources differently depending on the region. For example, Iowa and Louisiana had minimal water impacts, but West Texas and parts of California experienced more water stress.
The researchers also discovered that using reclaimed water, such as treated wastewater, for SAF production could significantly reduce freshwater demand and ease water stress in areas with limited water supply.
This research highlights the importance of using non-traditional water sources, like reclaimed water, to make CO₂-to-fuel technologies more sustainable. By doing so, the U.S. can meet its future energy needs while protecting freshwater resources.
The CO2Rue WATER module is just the beginning. Researchers from Argonne and DOE's National Renewable Energy Laboratory (NREL) are continuing to work together to improve the sustainability of emerging energy technologies.
Their goal is to ensure that CO₂-to-fuel technologies can scale up to meet climate goals without overburdening water resources.
"This tool will help guide critical decisions and improve the environmental performance of CO₂-to-fuel technologies," said Michael Resch, who leads CO2Rue.
With the insights from the CO2Rue WATER module, scientists and industry leaders can make smarter choices about how to produce low-carbon fuels in a way that conserves water and supports a sustainable future.