21 August 2019
The catch with carbon catching
Published online 8 April 2019
Capturing the carbon dioxide released by fossil fuel power plants is a poor alternative to renewable energy options.
Efforts are underway to capture and store the carbon dioxide released when coal, oil and natural gas are burned for electricity generation. But a study led by Sgouris Sgouridis at Khalifa University in Abu Dhabi suggests that investing in renewable technologies generally provides a better energy return than carbon capture and storage (CSS).
“Our research is going against the grain by challenging perceptions of the need for CCS,” says Sgouridis, who collaborated in the analysis with researchers in USA, UK, Norway and Italy.
“This paper correctly concludes that carbon capture and storage is a waste of energy relative to investing in clean, renewable wind and solar,” says energy and climate scientist Mark Jacobson of Stanford University, USA, who was not involved in the analysis. The paper could have gone even further to emphasize the air pollution and mining damage associated with fossil fuel use, which is avoided with renewable energy sources, he adds.
Sgouridis became interested in undertaking the analysis when his own research, indicating that renewable energy was becoming the cheapest energy resource, conflicted with the prevailing views supporting CCS. He and his colleagues performed a net energy analysis of carbon capture and storage systems in comparison with solar and wind power generation. In essence, they compared the ratio of net energy output over energy input for each technology.
“We show that constructing CCS power plants for electricity generation is generally worse than building renewable energy plants, even when we include the effects of storage systems like batteries and hydrogen,” says Sgouridis. The researchers also discuss significant challenges that CCS promoters would need to address to upscale the technology sufficiently for it to become useful. “These challenges should make the energy policy community very apprehensive about relying on such a solution rather than considering it as a last resort,” Sgouridis says.
He is careful to acknowledge, however, that the research team is not dismissing the use of CCS altogether, but only challenging its use in fossil fuel electricity generating systems. “CCS could be a perfectly valid tool for reducing greenhouse gas concentration in the atmosphere,” he says. But the potential of CCS to tackle the problem of carbon dioxide already in the atmosphere should not be used to encourage continued fossil fuel burning rather than investing in renewable energy sources.
Sgouridis, S. et al. Comparative net energy analysis of renewable electricity and carbon capture and storage. Nat. Energy https://doi.org/10.1038/s41560-019-0365-7 (2019).