By Will Brown
Last January, Elon Musk announced in his usual blunt style he would be funding the XPRIZE Carbon Removal prize for carbon capture technologies. The responses were filled with pictures of trees – mocking Musk for his apparent ignorance of nature’s carbon-capturing technology. But could it really be that simple?
The average hardwood tree will sequester around one ton of carbon dioxide within forty years. In 2019, humanity released around 33 billion tons into the atmosphere. We’d need to plant 33 billion trees just to counteract the emissions for one year, and that wouldn’t take effect for at least forty years. Assuming you were to plant around 500 trees per acre, that would be around sixty-six million acres – an area of land larger than the UK, every year. Although planting trees is rarely a bad thing, they are not enough on their own.
The IPCC (the UN agency responsible for studying climate change) noted in their most recent report that artificial carbon capture will probably be necessary to reach net-zero. Whilst countries can reduce a large amount of their emissions, there are several sectors – such as agriculture – that will be hard to reduce to zero. Therefore, carbon capture allows for net-zero to be reached whilst allowing these sectors to continue emitting. Although the technology is still in its infancy, there have been some promising developments recently.
Carbon Capture and Storage (CCS) is the most commonly mentioned. It involves the extraction and condensation of emissions from power plants, which are then stored underground. The technology for this is in place, but the prohibitive costs mean that there have been few successful attempts. There are currently around 18 large-scale CCS facilities worldwide. In the UK, there have been several failed attempts at this technology – one notable occurrence was when the Government spent around £100m on a competition for CCS, then scrapped it. If this technology is going to be widespread, it’s going to need to be cheaper – and that requires more funding.
Perhaps the more intriguing option of carbon capture is what’s known as Direct Air Capture (DAC) – unsurprisingly, this involves extracting carbon dioxide directly from the atmosphere instead of at the source. There are currently two approaches for this – either passing air through a chemical solution that removes the carbon dioxide or passing air through filters. DAC is currently operating on a very small scale, with nineteen small-scale plants currently operating worldwide capturing approximately 0.1 tonnes annually – for context, it is forecast by the IEA (International Energy Organisation) that this should be 85 tonnes per year by 2030 if we want to be on track of net zero by 2050. Similarly to CCS, the cost of this technology currently makes it unfeasible on a large, commercial scale. Despite the small scale, DAC has received significant interest from governments and companies alike – with companies like Microsoft investing in research into DAC, which theoretically should offset their emissions further down the line when the technology is developed.
There is currently a wide range of approaches for what to do with the carbon once captured. Carbfix are turning CO2 into stone. Project Vesta are turning it into limestone. CarbonCure are storing it in concrete – and for that they won an earlier XPRIZE contest for companies turning CO2 into products. There are also several plants currently in the works – such as a plant under construction in the US that aims to be operational by 2024 or the recently announced Storegga Dreamcatcher Project that has been awarded a grant from the UK government under its plans for a ‘Green Industrial Revolution’.
Elon Musk was not mad when he announced funding for carbon removal technology. It’s a field that’s on the cusp of spreading worldwide, and one in desperate need of further research. If countries are unable to reduce their emissions, carbon capture might be our only hope for reducing the impact on the climate – the sooner it’s commercially viable, the better.
Illustration: Anna Pycock