Oil companies and oil producing countries have settled on carbon capture and sequestration as their climate policy. Carbon capture is the idea that carbon can be captured from a smokestack. The product is high pressure carbon dioxide that is either stored underground or used to produce more oil.
One of the items that came out of COP27 is an emphasis on carbon capture and storage. For those of you who don’t know, the inflation reduction act contains a subsidy of $85/ton dollars per ton of carbon dioxide captured and stored from industrial processes and $60/ton used for enhanced oil recovery. It also includes a subsidy of $180/ton of carbon dioxide captured from the air if stored. Carbon capture and storage seems to be a coming thing. Natural gas and coal companies have determined that they can capture their emissions, and don’t have to be phased out after all. So they are now investing in exploration and drilling.
My personal biases in this regard is that I quit Citizens Climate Lobby over their support of it, although that was only the last of a lot of stupid things they did.
Literature for deeper reading
The process works by passing the carbon dioxide emitted by an industrial production process through a liquid which dissolves or has a constituent that reacts with the CO2. This liquid is then sent to a heat chamber and the carbon dioxide is liberated. It is compressed and sent where it is going to go.
C&EN news has a particularly good article. For those of you who are not engineers, chemical engineering is to a large extent about petroleum products, so C&EN news is going to be positive about this.
Bulletin of atomic scientists a negative review to balance the C&EN news article
Science direct the state of the technology.
Food and water watch for those who want to hear the bad parts.
The State of the Art
From Science direct
Carbon capture and storage (CCS), the suite of technologies to directly address CO2 emissions at source, is widely regarded as a crucial component of efforts to meet national and international climate change mitigation goals through the safe storage and sequestration of carbon emissions. The International Energy Agency (IEA) and Intergovernmental Panel on Climate Change (IPCC) analysis outlines that CCS remains integral to the reduction of global emissions and the meeting of international climate goals.1 The importance of CCS is made clear in the sustainable development scenario (SDS) of the IEA, which outlines the rapid transition to net zero.2 The technology alone accounts for up to 15% of cumulative emissions reductions to meet the global target by 2050, behind only renewables and energy efficiency methods (with these three sectors accounting for around 70% between them by 20503). To meet these targets, it is anticipated that around 5.6 gigatonnes per annum of CO2 will need to be captured and stored by 2050 using CCS technologies.4 However, despite this urgency, widespread roll-out of CCS remains slower than anticipated.5,6 It is encouraging that there has been recognition of the importance of global climate ambitions with the submission of nationally determined contributions (NDCs) and long-term greenhouse gas (GHG) emissions strategies from a number of countries, many of which highlight a growing commitment to CCS methods.7 Despite this, climate action efforts have fallen short of the internationally agreed targets, and it remains that individual government mitigation plans must be accelerated at a more rapid pace.
Although there is a lot of disagreement going forward, there is agreement that up till now this technology has been a disappointment. The more pro writers claim it clearly works, by which they mean it does remove carbon dioxide from waste streams, but in general it has been a disappointment financially and has been unreliable. Many projects have been cancelled, but that is probably because these were going to be attached to coal fired power plants, which were themselves cancelled. However, almost all working facilities remove carbon dioxide from natural gas at the well head, doing nothing for the climate. Moving forward there are new technologies, absorbents, and membranes and the big increase in subsidies. Also it looks like the technology is moving away from serving coal plants to serving natural gas plants. More importantly it appears to be moving into serving cement plants and steel plants, where the competing technology may be hydrogen, not renewables.
Carbon capture is expected to remove 85 to 90% of the carbon dioxide in a waste stream. Although, a Shell oil company paper said that moving to 95% would be easy, thermodynamics says that it isn’t. That residual carbon actually turns out to be a lot.
The two largest costs associated with the technology are its energy costs, and storage. It takes a lot of energy to capture carbon. A state of the art coal plant drops from 37% efficient to 27% efficient (nature). This increases the fuel needed by 39%. The fraction of carbon captured compared to no capture falls to 86%. This will raise the price of electricity and increases the value of the capture subsidy, since the cost is based on the amount of carbon captured not the kWh. The carbon capture subsidy in the bill is much larger than any subsidy for solar by the way. The other problem is that there is really no market for compressed CO2 other than enhanced oil recovery. So storage is where most of the carbon will go, a pure cost.
Carbon capture and storage is a loser for power production. Between the residual and the added cost, it merely makes fossil fuel generated power more expensive, and it is already even with renewables.
However, I do wonder if it has a future in some industrial technologies with big emissions like steel making, glass making, cement and ethanol production. In these industries there may be advantages, that outweigh the extra energy costs, and waste problems.