Carbon dioxide removal (CDR) systems, touted as techno-fixes for global warming, usually put more greenhouse gases into the air than they take out, a study published last month has confirmed.
Carbon capture and storage (CCS), which grabs carbon dioxide (CO2) produced by coal- or gas-fired power stations, and then uses it for enhanced oil recovery (EOR), emits between 1.4 and 4.7 tonnes of the gas for each tonne removed, the article shows.
Direct air capture (DAC), which sucks CO2 from the atmosphere, emits 1.4-3.5 tonnes for
each tonne it recovers, mostly from fossil fuels used to power the handful of existing projects.
If DAC was instead powered by renewable electricity – as its supporters claim it should be – it would wolf down other natural resources.
And things get worse at large scale.
To capture 1 gigatonne of CO2 (1 GtCO2, just one-fortieth of current global CO2 emissions) would need nearly twice the amount of wind and solar electricity now produced globally. The equipment would need a land area bigger than the island of Sri Lanka and a vast network of pipelines and underground storage facilities. (See endnote 1.)
Claims made that CCS could be “green” – by generating the energy from biofuels, and/or storing the carbon instead of using it for oil production – do not stand up to scrutiny either, the article shows.
The paper – “Assessing Carbon Capture: public policy, science and societal need”, by Read the rest of this entry »