A new study from the University of Michigan investigates which methods of carbon capture utilization and storage (CCUS) would be most beneficial for the climate and generate a “net climate benefit”. A net climate benefit, in this case, is explained as the emissions avoided by using the CCUS technology are greater than the emissions released by its utilization.
The study examines 20 carbon capture utilization and storage pathways and places them in three categories of usage of the captured CO2 – concrete, chemicals, and minerals. Those categories are ranked by how much they benefit the climate.
The results show that only 4 of the 20 pathways have a greater than 50% chance of generating a “net climate benefit”. Previous studies have revealed that captured CO2 could reduce emissions by up to 15% by 2030 as 6.2 gigatons of CO2 could be consumed annually by 2050 by CCUS technologies for the production of products in the above categories.
The four pathways that are more than 50% net climate beneficial, include two methods that use CO2 to mix concrete, one method to make carbon monoxide from methane, and a method to produce formic acid through the hydrogenation of CO2. All methods assume captured emissions from natural gas power plants in the calculations.
Carbon Capture Vs Renewable Energy
The study also compares the emissions from renewable energy electricity generation. It concludes that electricity produced from renewable sources such as wind often leads to a greater climate benefit if it is supplied to the grid to offset fossil fuel emissions, instead of being used to make carbon capture and utilization products.
“Currently, there is a greater opportunity to reduce carbon emissions by using renewable energy sources to displace fossil fuel-based electricity generation than investing in many of the CCU technologies,” according to the study co-author Greg Keoleian, director of the Center for Sustainable Systems.
Apart from those four pathways that provide the most climate benefit, the study also concludes that the other methods will also save more emissions than they generate under the right boundary conditions. They will still make the products we need and be net climate beneficial, it’s just that the options to achieve that are more restricted.
The paper also points out the necessity of more rankings and research into emissions savings of CCUS methods and technologies to help prioritize future strategies that would provide the biggest climate benefit of using captured CO2.