But that leads to another question. What do we do with all that carbon dioxide? Storing it underground is one option. But in an article published on March 29, 2018 in the scientific journal Joule, a group of Canadian and U.S. scientists describe an even more intriguing solution. Captured CO2 could be converted into other molecules to create fuels to store energy generated by wind turbines or solar panels, as well as to supply raw materials to make plastic and other products.
"Consider this as a form of artificial photosynthesis," Phil De Luna, a doctoral candidate in Materials Science Engineering at the University of Toronto and one of the article's authors, explains. "Plants take CO2 and sunlight and water and make sugars and other things they need to live. We're taking energy and CO2 and converting it into things we can use."
According to De Luna, converting excess CO2 to fuel as a storage medium would solve one of renewable energy's intermittency problems — that is, the dip in output that occurs when the sun goes behind the clouds or the wind stops blowing. And as a liquid, it also would be easier to transport than energy stored in heavy, bulky batteries.
When it comes to renewable energy, "There's a huge gap in storage right now, and this CO2 provides a solution," De Luna says.
Captured CO2 also could be used to make feedstocks such as ethylene, a chemical feedstock derived from oil and natural gas that's the starting point for plastics (as this primer from Pennsylvania State University details). That would not only store the carbon, but also help reduce the demand for oil and gas. The process could even provide a solution for the growing environmental problem of plastic pollution, much of which makes its way into the world's oceans. Plastic could be recycled more effectively by burning it, capturing the CO2 and using it to make new plastic. "Now, you've got a closed loop that could reduce plastic waste," De Luna explains.