CCS How It Works

A coal plant emitting 820 gCO2/kWh could, in theory, capture 90% of that CO2 before it reaches the atmosphere. The catch: separating CO2 from flue gas is thermodynamically expensive, consuming 15-30% of the plant's own output. You spend energy to undo what combustion just did.

Carbon capture and storage (CCS) works in three stages. First, capture: chemical solvents (usually amines) absorb CO2 from flue gas, then release it when heated. Flue gas is only 12-15% CO2 (the rest is nitrogen), so the solvent must process enormous volumes to extract a dilute target. Second, compression: captured CO2 is compressed to a supercritical fluid for pipeline transport. Third, storage: injection into deep saline aquifers or depleted oil and gas reservoirs at 800+ meters depth.

Calculate the energy penalty. A 500 MW coal plant with CCS diverts 25% of its output to run capture equipment: 125 MW consumed, 375 MW delivered. Same fuel input, 25% less electricity sold.

If CCS captures 90% of emissions, what happens to the plant's LCOE?

The cost math. The energy penalty means burning more fuel per net kWh. Capital costs for capture equipment add $40-80/MWh. Total cost of coal with CCS: $100-150/MWh, often exceeding wind and solar.

CCS is not a technology problem. It works. The question is whether its cost and energy penalty make it competitive with alternatives that produce zero emissions in the first place.

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