The Intergovernmental Panel on Climate Change says that mankind will have to start removing 12bn tonnes of carbon dioxide from the atmosphere every year if it wants to limit global warming to the relatively safe level of 1.5°C.

That amount equals almost one third of the current global carbon emissions.

Carbon-capture-and-storage technology will therefore have to move to the mainstream, and for that to happen various challenges need to be tackled, including cost and a seeming lack of economic interest.

Zurich-based company Climeworks, a spin-off from ETH Zurich (the Swiss Federal Institute of Technology), is one of a handful of pioneers looking for a solution.

The start-up hopes its transportable technology that captures CO2 from the atmosphere will be removing 1% of the world’s emissions every year by 2025. The firm’s head of sales Daniel Egger told Tereza Pultarova how the technology works.

How do you capture carbon emissions?

We have developed Direct Air Capture technology that doesn’t need to be installed at a power station or any other industrial facility to efficiently remove emissions. We use fans to suck ambient air through a filter made of a porous material that contains amines – chemical compounds derived from ammonia. The filter binds CO2 together with moisture, and CO2-free air exits the unit on the other side.

Once the filter is saturated, we heat it up to 100°C, which releases the CO2, dissolved in water. The gas is collected in a tank, and can be subsequently used for various purposes or stored permanently. The plant is fully automated, and can be controlled remotely.

How much energy does the process require?

It’s fairly energy efficient. Our first plant in Hinwil, near Zurich, which we launched in May 2017, is built on top of a waste incinerator, and uses solely waste heat from the incinerator’s operations.

How big are your carbon-capture plants?

Our technology is modular. Our basic industrial unit, which can capture 50 tonnes of CO2 per year, fits into a shipping container. You can build larger plants by stacking three containers on top of each other. Our Hinwil installation consists of 18 such collectors, and captures 900 tonnes of CO2 a year.

Is there commercial interest in your technology?

There definitely is interest. Our goal in the mid to long term is to reduce the cost of the technology to $100 per tonne of CO2 captured, at which stage it will become competitive.

The captured CO2 can be used for various applications, including as a fertiliser in a greenhouse or in the manufacture of carbonated drinks. The cost of CO2in the market depends largely on the location and distance from a source. There are many locations for which our technology would be competitive.

A lot of the companies that we are talking to are early-stage start-ups that are looking into things such as synthetic fuels and materials. They are evolving fast, like us. That means that in three years’ time there might be a lot more demand.

How can you reduce the cost of your technology?

It’s a matter of scaling up and making the process more efficient. We are experimenting with various filter materials to optimise the process, but we also want to build the machines smaller to reduce the cost.

Our technology is still very young; we started only nine years ago, so there is a lot of room for optimisation. It’s like the car industry in the 1910s, although we don’t think we will need 100 years to reach the same level of maturity.

Nine years ago, we were able to extract a few milligrams of CO2 in a laboratory. Now our technology is extracting a couple of thousand tonnes every year. To achieve our goal of capturing 1% of global emissions, we would have to extract around half a billion tonnes of CO2 per year.

We believe it is feasible from a technical point of view. This upscale is, however, challenging. It’s not only a technical matter. We also need to find customers, and to raise a lot of money.

Article Source: IMechE

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