Icelandic researchers using a novel technique have managed to rapidly stick unwanted carbon dioxide in solid rock, while others in Illinois have launched the world’s first commercial-scale bioenergy with carbon-capture and storage (BECCS) facility.
Researchers from a raft of universities and Reykjavik Energy have published in Science a paper detailing a process through which CO2 is in effect injected into basalt, a type of volcanic rock, where it rapidly mineralises, or turns to stone—in just two years.
While Iceland’s geothermal electricity production is much cleaner than if it were coal fired, it does still produce some CO2 due to release of subterranean gases. The amounts are tiny compared to combustion of coal, but Reykjavik Energy nevertheless wanted a way to stow these emissions. Captured CO2 is dissolved in water, which is injected into basalt where it reacts chemically with calcium, iron or magnesium to form a carbonate.
The breakthrough has climate watchers excited, as up to now, most attempts at scrubbing fossil fuel combustion of its carbon dioxide and then burying the CO2 as a gas or liquid underground or under the seabed still risk some leakage. This both undermines the desired mitigation and also worries those who might live nearby, as CO2 is heavier than air and could suffocate local residents in the event of a widespread leak. But carbon dioxide stored as a solid has no leakage risk and can remain in this form for thousands of years. The Science paper reported on a small pilot project of some 250 tonnes of CO2, but since then, the company has scaled up to 5,000 tonnes a year, and will soon double this figure.
However, the bulk of the hundreds of emissions scenarios produced by Intergovernmental Panel on Climate Change researchers that allow the planet to keep within the guardrail of 2°C of warming above pre-industrial times assume widespread adoption of so-called negative emissions technologies. This goes beyond carbon capture and storage (CCS), which at best can achieve only carbon neutrality, by achieving a net reduction in atmospheric CO2. In other words, sucking more greenhouse gases out of the atmosphere than we are pumping into it.
To go negative, CCS would have to be coupled with some other process that directly captures carbon dioxide out of the air. There are a number of different technologies that hope to do exactly this, including Squamish BC firm Carbon Engineering, but the simplest technology we have that takes in CO2 is of course plants. As they grow, photosynthesis draws down CO2 from the air. If we can then capture and bury the CO2 they produce when combusted, the overall effect is negative—a process known as bioenergy with CCS or BECCS.
There are some 15 BECCS pilot projects around the world, but the first major BECCS facility went live last year in Decatur, Illinois. Run by agribusiness giant Archer Daniels Midland, the firm captures emissions from its ethanol plant and then buries them in the sandstone over 2000 metres below the cornfields.
The Climate Examiner speaks to BC-based Carbon Engineering about the technology, the business and the policies that could make direct air capture, synfuels and carbon sequestration work.