Pre-Combustion Carbon Capture: CO2 Capture Technologies

Pre-Combustion Carbon Capture: CO2 Capture Technologies

There is no doubt that the main cause of climate change is the burning of fossil fuels, such as coal, oil and gas.1 When they are burned, these fossil fuels release carbon dioxide (CO2).2 This gas enters the atmosphere where it traps heat and causes the planet’s temperature to increase.3

Global emissions have now reached an all-time high.4 Could pre-combustion carbon capture be the solution?

What is pre-combustion carbon capture? 

Pre-combustion carbon capture is the removal of CO2 from fossil fuels before they are burned.5 The fuel is typically converted into a mixture of hydrogen and CO2.6 The CO2 is then separated from the hydrogen, allowing the hydrogen to be combusted cleanly.7 Meanwhile, the CO2 is compressed into a liquid for transportation.8 

Some deem this technology to be the only way to reach net-zero emissions targets.9 However, currently, of the 65 commercial carbon capture and storage facilities worldwide only 26 are operational.10 Collectively, these facilities can capture and permanently store around 40 megatons of CO2 annually.11 This figure pales in comparison to the 33.1 billion metric tons of CO2 emitted by the global energy sector in 2019.12 

How much does pre-combustion carbon capture cost? 

The capture process is expensive, with high deployment and energy costs.13 The necessary equipment can be added to existing power stations that were originally built without it.14 However, due to the large modifications required, it is more suitable for incorporation into new plants.15 Besides the cost of the conversion, pre-combustion capture is also expensive to run. A plant with this technology uses more fuel than one without.16 This additional fuel is needed to extract, pump and compress the CO2, which increases daily running costs.17

The type of industrial facility used with the carbon capture process will also affect the price.18 For example, in fertiliser manufacturing, CO2 is already produced separately in concentrated streams.19 As such, the cost for pre-combustion carbon capture is lower.20 For industries where the CO2 is not separated, such as cement production and power generation, the cost is much higher.21 For an integrated gasification combined cycle (IGCC) power plant, commercially available pre-combustion carbon capture technologies cost around USD $60 per tonne to capture CO2.22 

How does pre-combustion carbon capture work?

There are three stages to pre-combustion carbon capture. Fossil fuels are hydrocarbons, which means that they are a compound of hydrogen and carbon.23 The first stage involves splitting the fossil fuel into hydrogen and carbon monoxide.24 The carbon monoxide is then converted into CO2 by the water gas shift reaction (WGSR) process.25 Thirdly, the CO2 is separated from the hydrogen.26 This CO2 can be removed for storage or other uses, whereas the hydrogen can be burned without emitting CO2.27  

Theoretically, an industry with carbon capture can continue using fossil fuels without releasing harmful CO2. However, trapped carbon emissions are essentially worthless. As such, there is not much economic incentive for companies to invest in this expensive process.28 Clean energy sources are a more attractive alternative. Renewable energy is the fastest-growing energy source in the United States, accounting for over 17 per cent of net US electricity generation in 2018.29 It makes more sense from an environmental and economic perspective to transition to these energy sources, rather than rely too heavily on pre-combustion carbon capture.

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