Using Water to Achieve Lower-Emission Energy Infrastructure
A research team at Johns Hopkins is developing a water-based method for the electrochemical reduction of carbon dioxide that will reduce harmful emissions and generate useful chemical products.
Reducing carbon dioxide emissions is necessary to continue improving the sustainability of the energy infrastructure. Significant strides have been made in many sectors to contribute to this ongoing effort. At the state level, California is mandating that after 2035, all new cars sold must be zero-emissions vehicles. Larger emissions contributors like power plants must also adjust to reach emissions goals set by government regulations and industry standards.
Power plant carbon emissions. Image used courtesy of Unsplash
Industrial activity remains responsible for a substantial portion of worldwide carbon dioxide emissions, with estimates suggesting that this sector produces 30% of all emissions.
Worldwide carbon dioxide emissions from 1750-2021. Image used courtesy of Statista
More specifically, the power and electricity sector contributed more than 30 percent of carbon dioxide emissions from burning fossil fuels to generate electricity in 2022, according to the U.S. Energy Information Association (EIA) Of that figure, plants that burned coal and natural gas were responsible for 98 percent of CO2 emissions.
Renewable energy sources have decreased the total CO2 emissions from energy generation, but fossil fuel plants are still widely used.
Trends in energy sources used in power generation. Image used courtesy of the EIA
Researchers across the globe are striving to find ways to reach the end goal of carbon dioxide reduction, and engineers at Johns Hopkins have found that water can be used to create valuable electrochemical products by converting carbon dioxide into ethanol, propanol, and ethylene. Power plants might be able to use this method to substantially curb their carbon contributions.
Water and Carbon Coupling
The traditional method for converting carbon dioxide has relied on electricity and copper, and the result includes a significant amount of methane and carbon monoxide, which are not ideal byproducts.
A. Shoji Hall, an assistant professor of materials science and engineering at Johns Hopkins, has been developing a new approach that uses water to reduce methane and carbon monoxide emissions. The ultimate payoff of this method seems like a simple one, but it has important consequences. Instead of producing methane and carbon monoxide, this water-based process promotes carbon-to-carbon coupling (C-C coupling), thus creating valuable C2 products like ethanol.
Hall and colleagues saturated water with carbon dioxide and then ran electricity through it, causing the depletion of the concentration of water. This reduction decreased the availability of water molecules and subsequently led to more ethanol and ethylene production. The use of water improves carbon monoxide surface coverage which ultimately facilitates the C-C coupling that creates desirable C2+ products.
By developing this technique, the team at Johns Hopkins is harnessing the potential to produce useful chemicals through the electrochemical reduction of carbon dioxide.
Ethylene and Clean Energy
Hall has stated that the main form of carbon created by this process is ethylene.
Ethylene has many current uses and applications that make it a valuable commodity. According to the National Institute of Health (NIH), the primary usage of ethylene is in the production of polymers and industrial chemicals. The U.S. market for ethylene is substantial now and is projected to keep growing steadily.
U.S. ethylene market value sorted by industry. Image used courtesy of Grand View Research
Even though researchers at Johns Hopkins have pioneered this technique for breaking down carbon dioxide and producing other chemical products, if those products have no practical use and commercial industries have no incentive to use them, this method would lack practical efficacy.
So there is potential here to both reduce carbon dioxide emissions and produce valuable chemical alternatives, making this approach ideal in terms of its clean energy contribution as well as its private sector value.
The effort to reduce carbon dioxide emissions is a race against industrial activity and population growth, but innovations in the electrochemical reduction of carbon dioxide like this one hold the power to decrease emissions dramatically and move us toward a future of clean and sustainable energy.