IN-DEPTH: Developments in CCS technologies: time for direct air capture?

Carbon capture and storage technologies (CCS) are considered as one of the key mitigation tools to achieve the Paris Agreement goals. They differ from other solutions as they theoretically do not prevent industries from emitting according to their business as usual footprint, then capturing and storing the produced CO2 underground. The use of CCS as a compensation tool, however, is implicitly admitted in Paris Agreement article 4.1, which calls for a “balance” between anthropogenic emissions by sources and removals by sinks of greenhouse gases.

In 2005, China and the EU signed a partnership on developing a near-zero emissions coal. More, in 2009 the European Union adopted a continental common framework on CCS as some member countries were already using, or developing, such technologies. Technical, financial and ethical concerns have arisen, however, with respect to CCS technologies deployment feasibility, costs, and their possible negative impacts on the environment and human life in case of leakages.

Technically, CCS is defined as the process of capturing waste CO2 from sources such as fossil fuel power plants (flues), and transporting it to a storage site where it will be injected underground. Depleted oil/gas reservoirs and saline aquifers are usually considered as best options. The practice of injecting CO2 into almost depleted oil fields to partially recover their productivity has been in use for decades, yet long-term underground CO2 storage for environmental purposes is a relatively experimental technique.

According to data from the May 2017 Co2Geonet Forum, there are only 17 operational large-scale CCS facilities in the world, mostly (12/17) located in North America. 23 new facilities, however, are under planning or construction worldwide, with China at the forefront (7 under planning, 1 under construction).

According to the IPCC, the possibility for a modern underground storage site to experience leakages is highly improbable.

The International Energy Agency (IEA) therefore urged an acceleration in the uptake of CCS to cover deep emission cuts across cement, steel and chemical industries; the Global CSS Institute stressed that safe CSS technologies have already been in use for over 40 years, and that CSS is the only climate mitigation tool that can avoid the stranding of the trillions of dollars of existing fossil assets in the years to come.

Financial, rather than technical concerns, are limiting the spreading of CCS technologies as previous IPCC studies found capturing and compressing CO2 may increase the energy needs of a coal-fired CCS plant up to 40 percent, to be added to CO2 transportation costs in the case the plant is located far from the storage site (CO2 is mostly transported through dedicated pipelines – thus, if the building of a totally new transport infrastructure is needed, the investor must also consider to bear those costs).

The marginal cost to produce each new unit of energy may therefore increase to a point where economic gains will be likely scant in absence of specific incentives or regulation. In this sense, the oil and gas industry is stimulating regulation to encourage CCS by creating the case for coupled CCS incentives and CO2 taxation, as remarkably asked by Shell upstream director A. Brown in February 2017.

Direct air capture (DAC) is perhaps the most innovative CCS technology, yet largely unexplored. Information about the effective deployment of a commercial DAC plant in the surroundings of Zurich, Switzerland, gained media attention in June, 2017 as the experimental application has been advertised as cost-effective, modular, and void of geographical restrictions.

Functioning scheme of the direct CO2 capture plant in Hinwil, CH (source: Climeworks)


The producer, Climeworks, announced the ambitious goal to sell and deploy as many machines as to reduce global emissions by 1 percent each year by 2025. The plant costed $3-4 million and has been positioned on the roof of a municipal incinerator, which provides low-cost heat used in the process of CO2 capture. Captured carbon is then transferred to a nearby fruit and vegetable company, which uses it to boost the growth of its greenhouse products. The entire operation, therefore, is aimed at creating a sustainable circular carbon economy, with reduced transportation costs and no underground injection.

Until now, DAC technology has been considered too costly. Climeworks, however, claimed an operational cost of roughly $600 per tonne of CO2, with a long-term target price of $100 per tonne as production will increase and scale economies will emerge (in sharp contrast with MIT studies, estimating an average cost of $1000 per tonne). In order to reach the target price, Climeworks states, it will need a boost in demand and R&D to overcome current production methods.

Further developments in CCS are opposed by many environmental activists and movements; the recent failure of the billions-worth Kemper CCS project, in the US, even amplified concerns among prospective CCS investors – the plant costed USD 7.5 billion in seven years, and has now been reconverted to a classic natural gas plant due to unexpected technical complexities.

Although based on emissions, yet void of underground injections, DAC technology could represent a promising opportunity for strategic carbon-intensive industries if applied as complementary to a wider range of mitigation measures and given the necessary technology and support. The development of larger DAC plants in the future will certainly imply new and concrete solutions in terms of effective CO2 reutilization, or storage, to effectively reduce large-scale emissions.


This article was first published on ICCG’s International Climate Policy Magazine n. 47.


(Image: Paradise Fossil Plant. Photo credit: Tennessee Valley Authority/Flickr)