Carbon Capture

Don’t Fall for Big Oil’s Carbon Capture Deceptions – Carbon capture technology is a PR fig leaf designed to help Big Oil delay the phaseout of fossil fuels

Carbon dioxide removal is not a current climate solution — we need to change the narrative
Drastically reduce emissions first, or carbon dioxide removal will be next to useless.

Thermodynamics of air capture of carbon dioxide
Comment: Thermodynamic energies are best case scenarios, usually involving slow, reversible processes. But real processes that involve energy transduction typically operate with 30-50% energy efficiency. Take compressing CO2 to supercritical state. He doesn’t consider the energy efficiencies of the compressors. He doesn’t factor in the cooling required. He doesn’t factor in CO2 transportation energy costs. CO2 transportation, in pipelines or trucks, is a big energy burden. And the energy required to pump it underground or under the sea is another big cost. Power plants that capture CO2 at the source produce only 60% of the power that they do without CO2 capture. It only takes 3 50% efficient processes to reduce the overall efficiency by 8x.

Carbon removal isn’t weird anymore. That worries scientists.

High cost, low profitability and storage challenges: Is carbon capture a realistic climate solution?

Continuous carbon capture in an electrochemical solid-electrolyte reactor
Comment: The low energy consumption corresponded to a carbon capture rate more than 1000 times lower than the “high carbon capture rate”. Even at the pitifully low carbon capture rate, the energy required to capture one CO2 molecule is 42% of the energy produced by burning one methane molecule. If you look at the Supporting Information (also attached, Figure S31) you find that the energy requirement at the “high carbon capture rate” is over 3 times greater than the value they report in the main text. At this capture rate, 25% more energy is required for capturing one CO2 molecule than was produced in its generation. And, this is just the energy required to concentrate the CO2 to 1 atmosphere. They still haven’t done anything with it and they’re already CO2 positive.

Slowing Climate Change by Carbon Capture
Comment: Even with the 20% residual, he needs 4400 1-megaton per year DAC plants. That means 31,000 square miles of solar panels to run the DAC plant. Then the energy required to sequester the CO2 has to be added in. Green plant photosynthesis removes 10.5 petamoles of CO2 per year – this is 462 billion tonnes of CO2 per year. Clearly there is already a DAC system in place that runs 100% on solar energy. The solution is to stop producing even the 20%. The residual 20% is not a given – it’s an “I give up.” Fertilizer production, for example, can be driven with solar electricity – people are working on that. If, like he says, money is easy, then there’s no problem.