Swiss company Climeworks uses carbon dioxide to boost plant yields.

One thing is clear: carbon dioxide concentrations in the air are higher now than they’ve ever been. I’ve read estimates that say it’s the highest in 800,000 years. But if you take a more conservative estimate, it’s 400,000 years. That’s the figure the US National Aeronautics and Space Administration (Nasa) gives.

According to Nasa, during the Ice Ages, CO2 levels were around 200 parts per million (ppm), and during the warmer interglacial periods, they hovered around 280 ppm. In 2013 however, CO2 levels surpassed 400 ppm for the first time in recorded history.

“This recent relentless rise in CO2 shows a remarkably constant relationship with fossil-fuel burning, and can be well accounted for based on the simple premise that about 60 per cent of fossil-fuel emissions stay in the air,” Nasa says.

As we’ve all learned in science class, plants take in CO2 for photosynthesis so they’re a natural way to absorb CO2 from the air. The problem is that we’re producing far more CO2 than the plants can absorb. Either we find ways to reduce CO2 emissions or we need to find ways to get rid of it. Or better still, transform it into something useful.

One way to remove CO2 from the air is to turn them into stones. A company called CarbFix in Iceland is doing just that. It pumps CO2 emissions underground and alters it chemically to create stones. What the researchers do is mix carbon dioxide and hydrogen sulphide with water, and inject it into volcanic basalt located 1000 metres underground.

When basalt is exposed to CO2 and water, the carbon turns into a white, chalky solid. This process was initially thought to require up to a decade to happen but recent experiments have shown that stones can be created in mere months, making this a practical solution for storing CO2 underground.

Cement is the most manufactured material on earth and it involves producing a lot of CO2 as a by-product. For every tonne of cement produced, about a tonne of CO2 is produced too. A company called Carbicrete has found a way to make concrete without using cement. Instead of using cement to bind together the concrete, the company uses steel slag, a waste by-product of the steel-making process. “We’re taking garbage and we’re turning it into a valuable product and solving climate change all in one step,” said Carbicrete CEO Chris Stern.

Meanwhile, another company called CarbonClean in India has successfully used CO2 to create baking soda. The company is making use of the CO2 produced by its coal-fired power plant in the city of Tuticorin to create the baking soda which is used in many industries including baking, glass manufacturing, sweeteners, detergent, paper products and medicine. Interestingly, this initiative has proven to be commercially-viable and doesn’t involve any government subsidy.


Nasa‘s chart.

Carbon capturing

The product that probably has the most potential however is fuel. Companies like Opus 12 and Dioxide Materials — both from the USA — have been able to convert CO2 into methanol. Meanwhile, South Korean researchers from the Korea Advanced Institute of Science and Technology have found a way to create methane from carbon dioxide.

All these efforts to create products out of CO2 involve something called carbon capture, which entails sucking CO2 from either industrial plants or from the air. The former is easy enough and not costly but the latter is both technically difficult and very expensive. It has been estimated that it costs up to 12 times as much to capture CO2 from the air as compared to capturing it from a fossil fuel plant.

Capturing CO2 at a factory chimney could cost up to US$80 (RM327) per tonne, according to the Center for Climate and Energy Solutions. In contrast, carbon capture from the air can cost up to US$1000 per tonne. However, a Swiss company called Climeworks says it can do so at US$600 per tonne.

Carbon capturing is done with the use of special filters. Air is drawn into the plant and the CO2 within the air is chemically bound to the filter. Once the filter is saturated with CO2, it’s heated to around 100C. The CO2 is then released from the filter and collected as concentrated CO2 gas.

In Climeworks’ carbon-capturing plant in Hinwil, Switzerland, 18 large metal fans suck in air to collect CO2. This direct-air capture system can gather about 900 tonnes of CO2 every year. That’s approximately the amount of CO2 released by about 200 cars.

Interestingly, this gas is then pumped to a large greenhouse located nearby where vegetables are grown. The company says the CO2 helps to boost the plants’ photosynthesis and increases its yield by up to 20 per cent.

Carbon to products

The company’s end-game of course isn’t to produce healthier vegetables but to find a way to cost-efficiently capture carbon dioxide and sell concentrated versions of it to various companies that can make use of it to create products.

At US$600 per tonne, this is still a steep price to pay for CO2. The company says that this is because it’s still early days and that they had to build the plant from scratch as a proof-of- concept. The company officially opened in June.

Costs should drop when more plants are built and there are economies of scale. “The magic number we always say is US$100 per tonne,” says Climeworks founder Jan Wurzbacher, who estimates that this can be achieved within two or three years.

Let’s hope companies like Climeworks can bring the price down. Being able to commercially capture carbon and turn it into products is crucial to our future wellbeing. The global population is only expanding, not decreasing, and as more people populate the earth, there will inevitably be more CO2 pumped into the air. Reducing emission is idealistic but not realistic. We need to be able to convert it into something useful instead.

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