Capturing carbon emissions before they enter the atmosphere is a white whale for the fossil fuel industry.

In theory, if a power plant or a factory could easily eliminate carbon emissions by filtering them out of flue gas, then the plant would be able to pursue business as usual with some simple retrofits—no threat of future regulations mandating lower emissions, no push to switch to completely new technologies.

The problem is that carbon capture is energy-intensive and expensive, it doesn’t capture all the carbon dioxide being released, and it’s not always clear what to do with the gas after it’s captured. (The current best option is to find underground caverns in which the carbon can be stored, or sell the CO₂ to older oil fields for enhanced oil recovery.)