A WSU research team has received a Department of Energy grant on a project to capture carbon dioxide from the air and mix it with hydrogen to create a carbon-negative liquid fuel.
With the $400,000, one-year grant, the research team, which includes scientists from Lehigh and Arizona State Universities, will develop their plan that would recycle carbon emissions that contribute to climate change and convert them to a cost-competitive liquid fuel. They will develop an economic study showing how their fuel could cost less than $800 a ton.
“This is the first attempt to combine green hydrogen with direct air capture carbon, so you’re making a fuel that is carbon negative, and when it’s burned it’s neutral,” said Dustin McLarty, the project leader and an associate professor in WSU’s School of Mechanical and Materials Engineering.
Wind and solar are currently the cheapest way to produce energy in the world, but they don’t work well for some uses. They often require transmission lines from distant places and battery energy storage. For many energy uses, such as for ocean-going shipping, people also need the convenience of high-energy liquid fuels that fossil fuels provide. Because renewables are so much cheaper than fossil fuels, researchers are hoping that synthetic fuels made from renewables can someday displace fossil fuels purely on an economic basis, said McLarty.
“The one thing that is holding back renewable development is that of all the great sites to place them, currently they can only be put in places that are near large transmission infrastructure,” he said. “There are entire swaths of this country with great renewable energy and land that has little or no farming value that electro-fuel technologies could utilize.”
The WSU project aims to show how to efficiently make use of renewables to produce cost-competitive methanol. Currently refined from fossil fuels, methanol is most often used to make plastic and other chemical products. Although it’s generally expensive, it can work as a liquid fuel. It’s easy to work with and has good energy density, McLarty said.
In their project, the researchers would use water and electricity produced by solar panels or wind turbines to produce hydrogen. Then, they would combine the hydrogen with carbon and oxygen captured from the atmosphere to produce the methanol.
Capturing carbon from the atmosphere and sequestering it is of interest as a way to slow global warming, but it is expensive. It takes a lot of energy to capture it, purify it for sequestration, and then pump it into the ground for storage, said McLarty. For their work, the WSU team doesn’t need to purify the carbon dioxide or put it in the ground.
“We’re getting rid of two-thirds of the system,” he said. “We only have to do the capture part. We can use the crude carbon dioxide and attach it to the green hydrogen and make a high-value fuel product.”
The team is working to improve the yield per pass, which would lower costs. They would also eliminate gas compressors and replace them with water pumps, resulting in a 10 to 15% energy savings and associated cost reduction.
“We’re trying to use the waste of one subsystem to replace energy consumption in the other subsystems,” he said.
On the hydrogen side, McLarty is working on scaling up a WSU-patented ceramic manufacturing technology that allows for high-pressure, high-temperature hydrogen production. The technology can convert about 95% of renewable energy into green hydrogen as compared to about 70 to 75% for the predominantly used, low-temperature technology.
The researchers will conduct an economic study and life cycle analysis to understand the cost of bringing the methanol to the market. They will also test carbon capture material at higher temperatures with the goal of making use of waste heat and will study pressurized co-electrolysis of CO2 and steam to produce a syngas similar to fossil derived syngas. After a year, the researchers will design benchtop scale experiments to validate the technology concept.
“This is a great opportunity to take fundamental material science developed and patented at WSU and see it impact the real world in a positive way,” said McLarty. “If we can make it easier to drill the sky than drill the ground, that’s fabulous.”