High hopes for carbon capture and underground storage 9/05/2024

By AFP - Agence France Presse

High hopes for carbon capture and underground storage

Capturing carbon dioxide (CO2) from the atmosphere and storing it underground “sounds too good to be true”, a climate expert told AFP, but the technology to increase its capacity tenfold is already being tested.

The Intergovernmental Panel on Climate Change (IPCC) recognizes carbon capture and storage among the solutions for eliminating CO2, without giving it a central place in its models.

“The small DACCS (direct air capture carbon storage) ecosystem is becoming more diverse... but we don't know exactly where it will take us” in the fight against climate change, said Oliver Geden, a member of the IPCC and an expert on carbon dioxide removal.

Even if the capacity to capture CO2 reaches two billion tons by 2050, compared to just 10,000 today, as suggested by optimistic projections in an Oxford University report, the experts are categorical. First, we must massively reduce emissions of greenhouse gases such as CO2 into the atmosphere and consider carbon capture and storage only for emissions that cannot be eliminated.

Companies like Microsoft, Amazon, Airbus, and even Lego are already paying more than US$1,000 per ton of CO2 captured and stored - in the form of carbon credits - to offset their emissions.

- How it works - CO2 molecules in the air

The CO2 molecules in the air pass through large fans and are absorbed by a liquid filter or deposited on a solid filter.

When the filters are full, the fans close, and the filters are heated to high temperatures, above 120 degrees Celsius for solid filters and 900 degrees Celsius for liquid filters, to release the pure CO2.

This heating requires substantial use of energy and the development of these technologies on a large scale depends on the availability of electricity or heat from renewable energy.

Although chemical compounds can be reused, the environmental impact of their large-scale production has not yet been studied.

CO2, in a compressed gaseous form or dissolved in large volumes of water, is then transported and injected into porous rocks located hundreds of meters (several thousand feet) below the surface.

- Where it's happening -

Three commercial facilities are in operation, but only Orca, in Iceland, stores CO2 instead of reusing it as an ingredient in synthetic fuels, building materials, or refrigerants.

Since 2021, Orca has been absorbing 4,000 tons of CO2 per year, the equivalent of a few seconds of global emissions.

Its neighbor Mammoth, also developed by Swiss start-up Climeworks with Icelandic partners and presented on Wednesday, will absorb up to 36,000 tons a year.

In comparison, two billion tons of CO2 are “eliminated” each year, mainly through reforestation and forest protection, according to Oxford University. This compares to the 40 billion tons emitted worldwide last year.

Around 30 projects have been commissioned in the United States, the United Kingdom, Iceland, the Gulf States, and Kenya, with the capacity to store around 10 million tons of CO2 by 2030, according to the International Energy Agency.

More than 100 other projects with and without storage are being developed, but lack financial guarantees.

The United States has put $3.5 billion on the table, but this includes CO2 reuse projects.

The European Commission, Canada, the United Kingdom, and Japan are also exploring the option.

- The costs -

While carbon capture and reuse by the oil and gas sector dates back to the 1970s, direct capture from the air is a much more recent development, as it was not considered economical.

The cost of these technologies is estimated at between $600 and $1,000 per ton of CO2 captured, according to the IPCC, but could fall to between $100 and $300 in the coming years.

Geden applauded the proliferation of start-ups in the sector but said he believed “a threshold was crossed” when the pioneering Canadian company Carbon Engineering was bought by US giant Oxy Petroleum in 2023 for $1.1 billion.

Since then, the fate of carbon capture has been in doubt, as its reuse, rather than storage, is likely to be more lucrative for the big oil companies positioning themselves in the booming market.

mdz/ico/giv/rl