Tag: carbon capture

Counting on …day 89

17th June 2025

Carbon capture and storage (CCS) is one of the low carbon processes promoted by fossil fuel companies as a low carbon product. CCS involves three stages:-

  1. Capturing the CO2 for storage – The CO2 is separated from other gases produced in industrial processes, such as those at coal and natural-gas-fired power generation plants, or steel or cement works..
  2. Transport – The CO2 is compressed and transported via pipelines, road transport or ships to a site for storage.
  3. Finally, the CO2 is injected into rock formations deep underground for permanent storage. (1)

CCS has been put forward as part of the global net zero ambition to tackle those industrial processes where it is difficult to reduce or remove carbon emissions – eg iron ore smelting, cement making and a small number of similar chemical manufacturing processes that unavoidably produce CO2 as a by-product. 

However CCS is still a technology in its infancy and currently has a negligible impact on reducing carbon emissions globally. It is also expensive and does itself require additional energy inputs.

“[There are] 50 operational CCUS projects globally, with about 44 under construction and more than 500 in some stage of planning. Operational projects are capturing about 50 million metric tons of CO2 per year (MtCO2/yr). If all projects in development were complete, estimated total CCUS capacity would be between 416 and 520 MtCO2/yr, which is around 0.9%-1.1% of today’s global greenhouse gas emissions.” (1)  

In the UK the Net Zero Teeside Power (NZT Power) project is being developed to capture the carbon emissions from a new gas-fired power station. The power station will be located in the Tees estuary and it’s  CO2 will be stored under the North Sea. The 743MW power station will probably supply about 1 to 1.5% of the UK’s electricity needs. The carbon capture technologies to be used is Shell’s CANSOLV, a technology used previously for CCS at  two coal fired power stations. It is an as-yet untried technology for gas power stations. Carbon Commentary comments further on this:-

“Typically, gas power stations emit an exhaust stream which is only about 3.5% CO2, a number far lower than most chemical processes and also well below the concentrations from a coal-fired power station. Capturing CO2 from a gas-fired power station is the most expensive way of reducing emissions from a static source.

“Assuming that the proposed NZT power station typically delivers electricity at an average price of £75 per MWh, the CCS will add between about 50% and about 100% to the cost of the power. The total bill to customers will range from about £112 to approximately £150 per MWh. These figures compared to costs of around £50 for onshore wind and solar.” (2)

CCS is clearly a developing technology but is surely one that is best reserved for decarbonising those manufacturing processes where there is no alternative solution and not as a means of allowing for the continued burning of fossil fuels to generate electricity when there are so many other carbon free options such as wind, solar and tidal. 

Further reading:-

https://www.scientificamerican.com/article/the-false-promise-of-carbon-capture-as-a-climate-solution/
https://www.reuters.com/business/environment/why-carbon-capture-is-no-easy-solution-climate-change-2023-11-22/
5 reasons carbon capture should not be relied upon to meet climate commitments
  1.  https://www.wri.org/insights/carbon-capture-technology
  2. https://www.nationalgrid.com/stories/energy-explained/what-is-ccs-how-does-it-work
  1. https://www.carboncommentary.com/blog/2025/2/12/the-costs-of-carbon-capture-and-storagehttpsassetspublishingservicegovukmedia6556027d046ed400148b99feelectricity-generation-costs-2023pdf

Counting on … day 87

16th April 2024

Green cement – part 2

As part of the need to reduce all greenhouse gas emissions to address the climate crisis, reducing emissions from cement production is essential. 

50% of the emissions come from the release of carbon dioxide as a byproduct during the clinker making process. One solution is carbon capture- capturing the CO2 before it escapes into the atmosphere, pressurising it to a liquid which is injected into rock strata deep underground.  This technology has yet to be developed for use at an industrial scale. 

Another solution is to replace the limestone with an alternative that produces less CO2 – such as magnesium oxide mixed with magnesium chloride solution. However such alternative cements may not have all the attributes of cement when in use – different construction methods may be needed.

40% of the emissions are attributable to the energy needed to heat the clinker kilns. Switching to renewable energy to replace coal is one solution but requires considerable investment in green electricity production and distribution. 

Using materials other than limestone – such as volcanic rock – that can produce clinker at lower temperatures is another possible solution. Another alternative is to replace a proportion of the cement with an alternative binder such as ground granulated blast furnace slag or pulverised fly ash. Again this may alter the properties of the cement and require different construction methods.

10% of the emissions comes from energy used in mining and transporting the raw materials. Energy efficiency and the use of renewable energy will be a way forward.

Further reading –https://theconversation.com/green-cement-a-step-closer-to-being-a-game-changer-for-construction-emissions-126033

(https://theconstructor.org/concrete/green-cement-types-applications/5568/