Removing greenhouse gases ‘is not a magic bullet to get to net zero’ | Carbon Capture and Storage (CCS)
Many top UK scientists working on carbon capture technologies do not believe they will be developed and scaled in time to reach net zero and limit global warming to 1.5C.
Experts speaking at a Greenhouse Gas Removal Hub event in London warned that these techniques, including direct air capture, biofuels, biochar, reforestation and advanced weathering, are not a silver bullet and should only be a fraction of decarbonization efforts.
Researchers were asked by event organizers whether they thought carbon removal targets would be met. Of 114 scientists present, 57 per cent said they were ‘not confident’ the UK would meet the 2030 targets in the net zero strategy of 5 million tonnes of artificial greenhouse gas removal and 30,000 hectares per year of tree planting; 25% said they were quite confident and 11% said there was no chance.
Scientists are taking part in a £70million government-funded competition to find the best ways to remove greenhouse gases from the atmosphere. These technologies are expected to start removing large amounts of carbon dioxide from the atmosphere by 2030, with the hope that the winning methods could be scaled up and ready for commercialization in two years.
The government seems, on the whole, confident in the fairly rapid development of carbon capture methods. The Department for Transport has said, for example, that greenhouse gas removal (GGR) technologies will allow Britons to take ‘guilt-free flights’ by the end of next year, but people involved in the program were less optimistic.
But when shown a government press release stating that these technologies will enable net zero flights by 2023, Professor Mark Taylor, Deputy Director of Energy Innovation at the Department for Business, Energy and Industrial Strategy (BEIS), seemed skeptical. He told the Guardian: “No, it’s not. We have to get people to believe that it can work, but maybe that claim is a bit cheeky. »
Gideon Henderson, Chief Scientist at the Department for Environment, Food and Rural Affairs (Defra), said: “GGR is difficult and expensive. And we cannot afford to see it as a substitute for offsetting ongoing emissions in sectors that can be decarbonized. This is no excuse not to decarbonise, so we need to reduce emissions anyway.
By far the most popular application-based technology to the program was direct air capture. This process involves removing carbon from the air, usually using giant fans, and heating it to a very high temperature. This carbon can then be stored in geological formations or combined with hydrogen to create synthetic fuels.
While ministers like the idea, those running the program believe it may not be the answer, due to the energy intensity required and the cost.
Taylor said: “People see it as having the biggest market, there has been funding from American companies – it looks like a silver bullet, there are a lot of people who like it. Ministers like it because they think, “Oh, that looks easy, you can get it out in the air and that’s it.” And that’s what attracts investment.
“I am very hesitant as to whether this is the best solution. It’s very, very expensive. So some of the other technologies may emerge as winners, but the good thing about our competition is that we choose the best.
The Guardian approached BEIS for comment.
Greenhouse gas removal methods tested with UK funding
Henderson said it was the “poster” of GGR, because “everyone seems to like it, and it’s nice to have more trees”.
However, he said trees “are not a panacea” due to the amount of land they require being taken out of food production, which then causes tensions with food security. There is also a tension between woodlands, which have more biodiversity benefits but grow more slowly, and forests, which grow fast and sequester more carbon sooner.
Storage in the ground
Although storing carbon in soil is a popular method, according to Henderson, there are concerns about how long carbon can be stored in soil and how it is measured. If the soil starts releasing carbon again soon after it is stored, it could cause problems, especially if it is not measured effectively and counted towards net zero goals.
He explained: “I think that if we see significant financial resources coming into this area to incentivize storing soil carbon without being able to measure it, and being sure of its permanence, there is a risk of continued emission of the storage that is not permanent or sufficiently well measured.
Dropping tiny particles of rock into the sea to cause chemical reactions that trap carbon in the ocean is a potentially very exciting technology, but it’s at an earlier stage than most other carbon capture methods. . It has interesting potential, because the ocean stores carbon in higher concentrations than in the air. It is even hoped that it could help reverse ocean acidification. However, there are also concerns that the process could upset the delicate balance of the oceans.
Direct air Capture
The idea of a machine that can suck carbon dioxide out of the atmosphere and permanently stick it into rocks is very appealing, and perhaps it’s no surprise that it’s the most popular technology for scientists trying to solve this problem.
But it is currently a very energy-intensive process. Taylor explained, “We have to use energy to extract the CO2the pure CO stream2 solid, so what we’re looking for is an integration that can lower DAC costs, and in particular lower CO extraction cost2 and energy costs of CO extraction2. Because right now there’s no point in capturing CO2 air, then using natural gas to run a thermal process to extract pure CO2 flow.”
While Henderson pointed out that this is carbon storage that is already happening on some scale in the UK and could be “a really powerful form of greenhouse gas removal”, biodiversity and pressure on land use are of concern. Indeed, growing crops often creates a monoculture and that land is taken out of food production.
Biochar is a stable, long-lived, carbon-like product obtained from heating biomass in the absence of oxygen. It is high in carbon and can be applied to land to sequester CO2 in the soil for a long time. This could be relatively easy and cheap, but one wonders how long the carbon would be stored and if it would have any negative impacts on the soil.