Iceland’s four largest CO2 emitters, three of which are aluminium smelters and the other a ferro-silicon plant, have signed a Letter of Intent with the Icelandic government to look for ways to become carbon neutral by 2040. The PCC silicon metal smelter at Bakki, which is another large emitter, is also expected to sign – “although our first priority is to get the operation running properly,” according to the environmental officer there.
The aim is to thoroughly investigate whether the CarbFix method for storing CO2 can become a viable option, both technically and financially, for storing CO2 emissions from these companies.
CarbFix was set up originally in 2007 in conjunction with the Hellisheidi geothermal power station, where CO2 is captured from steam and dissolved in water at pressure. The water is then injected into underground basalt rock at a depth of 500-800 m, where it forms carbonate minerals such as calcite within a few years. These carbonate minerals are stable on a geological time-scale.
Annual capacity at the Hellisheidi plant is around 12,000 tonnes CO2, which accounts for about a third of the plant’s CO2 emissions. The Hellisheidi plant also removes hydrogen sulphide (H2S) from the steam, but this will not be an issue with the companies intending to become carbon-neutral by 2040.
In 2017, a pilot-scale Direct Air Capture unit was added to the system: this process is independent of location as it mostly relies on energy in the form of heat, which is available as a by-product in numerous industrial processes. Unfortunately the technique is currently too expensive to be used for making heavy industry climate-neutral.
The project with heavy industry, which is expected to span five to ten years, will involve analysing the concentration of CO2 in emissions, so that similar removal techniques can be applied to those at Hellisheidi. The next step will involve design and manufacture of experimental equipment for capturing and injecting CO2, followed by design and manufacture of similar equipment on a larger scale.
The standard method of carbon capture and storage (CCS) involves pumping oil into old gas fields or using some form of carbon capture and usage (CCU). Edda Sif Aradóttir, who is project manager of CarbFix, says there are both advantages and disadvantages to traditional methods.
“The CarbFix method transforms CO2 into minerals within two years through a chemical process that happens naturally in nature, while traditional methods store CO2 in gas or liquid form. The procedure is thus of a completely different nature and CO2 is permanently removed,” she says.
She says that the main disadvantage is that it requires a considerable amount of water to dissolve the CO2 where chemical changes occur between water and rock. “On the other hand, the water needed by the procedure may be reused, which we in fact do up at Hellisheidi … we are working at developing the process even more so that seawater can be used,” she explained.
Funding for the CarbFix2 project has come from various programmes within the EU, including Horizon 2020, with collaborators in Toulouse, Barcelona and Zurich. CarbFix2 is designed to move the project on from a demonstration phase to one which will lead to an economically viable, complete CCS chain that can be used within Europe and globally.
Future research involves exporting the method to new injection sites in Germany, Italy and Turkey as well as Iceland, and further developing the method so it can be used offshore for permanent mineral storage of CO2 on the sub-sea floor. CarbFix proponents say that there is far more storage available in porous sub-marine basalts than required for the geologic storage of all the anthropogenic CO2 that will ever be produced.
I also wrote about this for ENDS Europe Daily today.