Does clean coal and CCS actually work?

Carbon capture and storage works technically but fails economically. Projects such as Boundary Dam in Canada and Petra Nova in Texas have captured millions of tonnes of CO2 from coal flue gas. But capturing 90% of emissions forces a coal plant to burn roughly 20–30% more coal to power the capture equipment, which typically makes coal-with-CCS about twice the cost of its renewable competitors (IEA, 2023).

For decades clean coal has been promoted as a technological saviour, but the term is often a marketing triumph: it has been used to describe everything from basic sulphur scrubbers to advanced carbon capture and storage. The underlying idea is simple — capture the CO2 at the smokestack and pump it deep into a saline aquifer or depleted oil field, and the coal machine can keep running without wrecking the climate. That vision attracted billions in public and private research funding, and technically it does work: Boundary Dam and Petra Nova have captured millions of tonnes of CO2 from coal exhaust by washing the flue gas with amine solvents, then stripping, compressing and piping the carbon to an injection site.

The main obstacle is not physics but economics. A CCS system imposes an enormous parasitic load on the plant: capturing 90% of emissions means burning roughly 20–30% more coal simply to run the capture equipment, making an already expensive fuel more expensive still. Set against the collapse in the cost of wind, solar and storage, coal with CCS typically lands at about twice the cost of its renewable competitors (IEA, World Energy Outlook 2023). The Kemper County plant in Mississippi is the emblematic case: launched as the flagship of clean lignite, its cost ballooned from USD 2.4 billion to over USD 7.5 billion before it was abandoned and converted to burn natural gas.

Even without CCS, making coal cleaner is expensive. To meet modern air standards a coal plant needs flue-gas desulphurisation scrubbers, electrostatic precipitators to catch fly ash, and selective catalytic reduction (SCR) to neutralise nitrogen oxides. These systems can cost hundreds of millions of dollars and consume roughly 10% of the plant's own electricity. In other words, cleaning up coal requires burning more coal to power the cleaning machinery — and in competition with cheaper, cleaner gas and renewables, that compliance cost is a decisive factor crushing the sector's economics.

There is also a boundary that is easy to overlook: CCS does nothing about the other dirty stages of the coal lifecycle — acid mine drainage, mountaintop removal, coal dust and toxic coal ash. Even if every carbon molecule were captured, the ecological scars of extraction would remain. This is why many environmentalists and energy analysts describe CCS as a technology permanently ten years away from commercial viability. The reasonable conclusion is a bounded one: CCS may still matter a great deal in hard-to-abate sectors such as cement and steel, but its ability to rescue coal-fired power generation has been squeezed out by steadily improving renewable economics.

Many environmentalists and energy analysts see CCS as a technology that is permanently ten years away from commercial viability.

This question is covered in depth in The Full Spectrum Every Energy Source Explained — A Singapore Perspective，第三章 3.7