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>That's probably too expensive right now Understatement of the decade. This is functionally the same as hefty, punitive fines for burning any fossil fuel at al
by dTal 5y ago
>That's probably too expensive right now
Understatement of the decade. This is functionally the same as hefty, punitive fines for burning any fossil fuel at all. The simple math is that closing the carbon cycle will always take as much energy as you got from burning it plus some extra, so it's never going to be economical to put the CO2 in the atmosphere and then take it out again.
- DennisP 5y agoYou're only closing the carbon cycle if you turn ambient CO2 back into fuel. If you bury the CO2, that's an open cycle and just you have the cost of concentrating CO2 and pumping it underground. In basalt formations it will turn into rock in a year or two. According to David Mackay, the theoretical minimum cost of concentrating the CO2 is 0.55kWh/kg.[1] The least carbon-intensive fuel is methane, which releases 0.18 kg/kWh, or for comparison, 5.55kWh/kg.[2] So the theoretical limit is that concentrating the CO2 will take a tenth as much energy as we get from burning the fuel. Of course we won't be maximally efficient but we have some room. Possibly cheaper methods include turning the CO2 into biochar, or accelerating rock weathering with something like olivine sand beaches. In these cases, the energy mainly comes from sunlight and waves. [1] https://www.withouthotair.com/c31/page_244.shtml https://www.withouthotair.com/c31/page_244.shtml [2] https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085.html https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085...