Climate Change | The uncertainty of carbon capture

For the past ten years, researchers and oil companies have been intensifying their research on the capture and sequestration of CO₂. Projects even go so far as to remove CO from ambient air₂ responsible for the greenhouse effect. Some of the scenarios in the recent IPCC report relate to the use of these controversial technologies.

Blue and red

The latest report from the Intergovernmental Panel on Climate Change (IPCC), released in early April, contained a graph on the cost of different strategies to combat climate change. Solar and wind energy, public transport and active transport (cycling and walking) were in blue. This means that their adoption would allow savings compared to the current situation.

CCS (English acronym for CO capture and storage)₂) was dark orange (US$50-100 per tonne of CO₂) and red (from US$100 to US$200 per ton), due to its high price.

Importantly, the assessment of the cost of the expansion of public transport and active transport does not take into account the value that individuals place on their comfort and the flexibility of the automobile or the social opposition to the projects. wind and solar power plants as well as power transmission lines. “We can’t put a price on everything,” observes Normand Mousseau, scientific director of the Trottier Institute at Polytechnique Montréal.

Chess

Two studies have recently reported on the many failures of CO capture and storage₂, a greenhouse gas released in particular during the combustion of fossil fuels. The most recent, published in February in the journal EarthOne by Dutch researchers, concluded that only 8 of the 40 existing technologies are effective enough to be used to achieve the goals of the Paris Agreement.

The other, published in September in the journal Energy Policy by American and Japanese researchers, concluded that the 232 major projects launched between 1995 and 2018 achieved results 85% lower than forecast for 2020. “There are a lot of technical problems to solve”, explains Gregory Nemet, of the University of Wisconsin at Madison, study co-authorEnergy Policy.

Mr. Nemet believes that the conclusions of the study ofEarthOne are encouraging – eight technologies are made quite mature – but others have a more negative point of view. “Eight appropriate technologies out of 40, that’s a success rate of 20%,” says Dominic Eagleton, of the British NGO Global Witness. He is the author of a report published in January on the low rate of capture of CO₂ of a Shell pilot plant in Alberta.

The future for a Texas oil company

Last fall, Occidental Petroleum unveiled to investors an ambitious CO2 capture and storage plan.₂. “In the next few decades, our CCS revenues will exceed our hydrocarbon sales revenues,” Occidental CEO Vicki Hollub said during a conference call with analysts from Houston. This project involves one of the pioneers of direct CO capture₂ atmospheric, the company Carbon Engineering, which has been testing a pilot plant in British Columbia since 2015. “You have to be careful with the assertions of a company seeking funding for its projects,” cautions Mr. Mousseau.

The a b c of CCS

Chemical processes capture CO₂ emitted by power stations and industries. Among these chemical processes, there is a principle similar to that of the old lime paint: certain minerals, when in contact with the air, absorb CO₂, which then becomes solid. CO₂ gas can then be extracted from this solid.

This CO mineralization₂ is often used for direct CO capture technologies₂ atmospheric, because the rate of CO₂ is much lower in ambient air – 420 parts per million (PPM), or 0.042% – than in factory plumes. Other chemical processes used for CCS work better with higher concentrations of CO₂. Then, you have to inject the CO₂ collected in underground reservoirs, which often have to be kept under pressure to make them watertight.

Leaks

One of the bones of contention is the extent of ‘fugitive emissions’ of methane, which occur during its extraction and transportation to power plants equipped with CCS technology.

Mr. Nemet estimates that this “energy cost” of CCS, which is partly due to fugitive emissions, is more like 20% to 30%, which means that methane power plants practicing CCS consume 1.2 to 1 .3 more methane to produce the same amount of electricity.

The other uncertainty relates to leaks from the pressure vessels where the CO is trapped.₂. “We only have a few decades of data on it and we’ve never had a deployment on the scale we’re talking about now,” says Mousseau. Tim Dixon, director of the CCS R&D group of the International Energy Agency (AIEGHG), believes for his part that these few decades are sufficient to consider that CO leaks₂ stored will not be a significant problem. Mr. Bonin points out that the AIEGHG has several oil companies among its members. “I would be very careful with this organization,” says Bonin.

Transform CO₂ in rock

Another method is to inject CO₂ in certain soil types, where it turns to rock within a few years.

For 10 years, a pilot plant of Carbfix, fueled by geothermal energy, has proven that the transformation of CO₂ in rock was fast enough to be considered CCS. Will this approach be inexpensive enough to be used in the fight against global warming? “Listen, the current price per ton of CO₂ is 100 euros in Europe, says Mr. Oelkers. But that ultimately only translates into a tax of 25 cents per liter of gasoline. We know that this is not enough to change the behavior of motorists. I’m pretty sure that CCS will cost less than 100 euros per ton, whether it’s technologies like Carbfix or CO injection.₂ gases in pressurized tanks. »

R & D or tax incentives for oil companies

Currently, 90% of CCS projects worldwide inject CO₂ in oil wells to increase production (Enhanced Oil Recovery or EOR), believes Mr. Oelkers. “If we take into account the entire life cycle, the EOR is not at all carbon neutral,” laments the geochemist from Toulouse. The United States includes EOR in eligible projects for climate program tax credits, while Canada does not.

“Right now, EOR is necessary for profitable progress,” says Nemet. Eventually, we will be able to do without them, but I believe that their inclusion in climate tax credits will advance CCS technology faster. Among all the experts interviewed, Mr. Nemet was the only one who defended the financing of the EOR within the framework of the fight against climate change. Even Mr. Dixon thinks it’s best not to have public funding for EOR “because environmental groups don’t like the association of CCS with fossil fuels”.

To read on Monday: our article on CO2 capture and sequestration projects in Quebec.