Negative emissions technology
CO2 converted to sold rock (Image: CarbFix)
Negative emissions technology
- The world’s plan by 2050: remove 8 billion tons of CO2 every single year and put it back underground (negative emissions).
- This calculation is based only on what humans are releasing. It doesn’t include the staggering volume of greenhouse gasses now being released by collapsing ecosystems
- The IPCC pathways assume negative emissions technology will be invented ‘spontaneously’ and rolled out across the planet. Currently, most tech that draws carbon from the atmosphere sells it as fuel, returning the CO2 straight back into the atmosphere.
- Some tech injects captured CO2 into depleted oil wells, to squeeze out the last few drops of oil, to keep us addicted to fossil fuels.
- Tech such as DACC is genuinely negative emissions. Most others are misleading at best, and at worst, dangerous greenwashing.
- The IPCC favours BECC: planting monoculture pines and taking away a large chunk of land needed to grow food.
- In spite of calculations under the current emissions trading scheme (ETS), almost all natural ecosystems including soils and the ocean permanently remove carbon from the atmosphere at no cost while also providing ecosystem services that we literally cannot live without.
- We recommend watching the videos as these expose the false claims and the loopholes many industries are legally exploiting.
DACC: Direct Air Carbon Capture with Sequestration (permanent storage as rock underground)
Genuinely captures and stores carbon (negative emissions). Innovative technologies combine to (a) extract CO2 from the atmosphere using renewable energy, and (b) convert it into solid rock (calcium carbonate) deep underground in basaltic rock within 2 years. Climeworks and Carbfix (Iceland, powered by geothermal energy which, unbeknown to most people, produces CO2 so is not entirely sustainable) are the only joint companies currently doing this (Fig. 1 and Videos 1 and 2).
Northern Lights in Norway have recently (March 2021) partnered with Climeworks to develop the same processes to store CO2 in deep basalt formations off the coast of Norway. Give the urgency of the climate problem, the company is developing the world’s first open-source CO2 transport and storage infrastructure to enable and encourage innovation and technology development in a fully transparent manner.
“The key is to identify the right place to inject and contain the CO2, which is trapped in microscopic rock pores by the same process that trapped oil and gas and natural CO2 for millions of years. Geologists look for a permeable rock formation that is stable and deep enough to ensure the CO2 is a dense fluid rather than a gas.
Close monitoring, using seismic data, is used to refine theoretical models and check that the CO2 is moving within the rock space as expected (this is known as “plume migration”). In Snøhvit, for example, plume monitoring shows some of the CO2 trapped in rock spaces due to capillary forces, some dissolved in brine and some mineralised into rock.” – Northern Lights
DAC: Direct Air Capture: recycles CO2 back into the atmosphere, ie, not ‘negative’
Removes carbon from the air using an exceptionally costly process, but instead of storing it, recycles it into more fuel, which means it goes straight back up into the atmosphere. For example, Carbon Engineering in Squamish, Canada, which calls itself ‘air-to-fuel’ technology, is backed by one of the dirtiest types of fossil fuel developers on the planet: the oil sands in Alberta. This is not negative emissions technology. It’s reselling used fossils fuels, claiming them to be climate-friendly or even more disingenuously, ‘carbon-free’:
“Imagine driving up to your local gas station and being able to choose between regular, premium, or carbon-free gasoline.” – National Geographic
While industries such as airlines and shipping are using DAC because there is yet no viable alternative to fossils fuels, some heavy fossil fuel industries use it as an excuse to continue business as usual, while claiming to be helping the planet (Video 3).
CCS: Carbon Capture and Storage underground
Fossil fuels are taken from the ground, burned by factories and power generating plans, and the CO2 they emit is captured before it goes into the atmosphere. They then have three options:
- Inject it onto oil wells to force out the last few drops of oil. This is called ‘Enhanced Oil Recovery’. Companies in the US enjoy massive tax breaks for ‘sequestering’ carbon this way. It’s the worst kind of greenwashing as it perpetuates oil addiction
- Inject the CO2 into sedimentary rock formations and dry aquifers. Given their past assurances about the safety of their operations, this raises concerns about the potential for CO2 leaking out over the coming decades. Potential leakage notwithstanding, it still means taking more fossil fuels out of the ground and burning them, continuing fossil fuel addiction.. Companies that claim to capture 100% of their CO2 doesn’t make them ‘carbon neutral’ unless every aspect of their business offsets 100% of all carbon costs for the full life-cycle of every aspect of their business including the cost of the materials used to build structures, make products, transport them, capture all of those emissions as well, and guarantee storing the captured CO2 gas underground indefinitely.
- As the price of carbon increases, market forces should incentivise heavy fossil fuel users to use processes that DACC use, ie store the captured CO2 in suitable rock formations.
BECCS: Bioenergy with Carbon Capture and Storage (growing and burning forests and plants)
“We found that in a majority of the areas where forests will be replaced more carbon is stored by keeping the forests.” – Smolter and Ernsting
BECCs is favoured by the IPCC in its modelling: plant lots of fast growing plants such as radiata pine, cut them down, burn them (‘bioenergy’) capture the CO2, inject the gas underground and hope it stays there or sell it for Enhanced Oil Recovery, burn that newly recovered oil, adding more CO2 into the atmosphere, grow more radiata pine…repeat.
“Despite the fact that Enhanced Oil Recovery leads to the recovery and burning of potentially vast quantities of fossil fuels which would otherwise have remained under the ground, use of CO2 for this purpose is classed as a form of CCS, a claim accepted even by the Intergovernmental Panel on Climate Change. ” – Smolter and Ernsting
For BECCS to work, it would mean replacing much of the existing native forest on the planet with fast growing trees, destroying irreplaceable, life-supporting ecosystem services and releasing carbon locked up in those forests and their soils. Additionally, by 2100 BECCs would also need to use around 25-46% of the land currently used to feed people (Video 4). While New Zealand may find ways to avoid some of these problems, the same cannot be said for developing nations keen to cash in other nations’ (including New Zealand’s) need to purchase carbon offsets in order to meet obligations under the Paris Agreement.
“Bioenergy with carbon capture and storage is expected to capture, on average, around 130 billion tonnes of carbon via planting crops for biofuel that are then burnt in power stations…. It is expected that an additional area of one or two times the size of India is needed for bioenergy crops by 2050.” – Dr Anna Harper, University of Exeter.
“My colleagues and I find that expansion of bioenergy in order to meet the 1.5C limit could cause net losses in carbon from the land surface. Instead, we find that protecting and expanding forests could be more effective options for meeting the Paris Agreement. ” – Dr Anna Harper, University of Exeter
Bioenergy from burning slash with CO2 pumped into greenhouses
Using heat from burn slash from radiata pine and waste plants, then pump the emitted CO2 into greenhouses to increase plant growth does seem like a good idea. However, while plants exposed to higher levels of CO2 may grow faster, their nutritional values are declining (video 5) and structurally weaker. This may limit the use of this process to growing short-lived non-edible products like flowers.
Hot Lime Labs in New Zealand uses this process. Climeworks also does this in Switzerland, although they capture the CO2 from DAC, not from burning biomass.
Further research is strongly recommended to assess the nutritional value of food grown using this method.
Carbon captured and stored in concrete
- For every metric tonne of cement produced, one metric tonne of CO2 goes up into the atmosphere
- The world uses 4 billion tonnes of concrete every year
- Additionally, fossil fuels like powdered coal are requited to to melt limestone, resulting in a more CO2 emissions
- The cement industry accounts for 8% of total greenhouse gas emissions
Several companies are now finding ways to permanently store CO2 in concrete. Not all are ‘carbon-negative’ as claimed, however the processes are innovative and look extremely promising to reduce carbon emissions. See their websites for more information:
Use algae to grow your own cement
Biomason uses a natural non-modified non-pathogenic bacteria to grow biocement® building material without heat, using a process similar to hydroponics. The species used is commonly found in natural environments across the world.
It takes around 72 hours for Biomason’s tiles to reach full cure strength (traditional concrete can take up to 28 days to cure) and the products is 3 x stronger than concrete.
In marine environments, self-sustaining natural marine microorganisms that source nutrients from seawater, are used to propagate calcium carbonate precipitation (similar to how beachrock is formed, but over much short time frames). The result is the sustained structural integrity of products with self-healing abilities. This process can be used to quickly built breakwaters and other ‘hard’ coastal/marine sturctures.
Suitable rock formations
The safest way to store CO2 underground is in places where the CO2 is mineralized, that is, it becomes a rock. This is the process used by Carbfix in Iceland for DACC. Considerable research and experimentation is currently underway to find locations and/or other types of minerals that can be used to enhance this process. If places to store CO2 underground can be found close to factories that produce large amounts of CO2, then the cost of storing carbon safely in rock formations will become much more appealing. As with all things, there are likely to be trade-offs. For example, one kind of rock called olivine may help with this mineralisation process:
“Our preliminary investigations have shown Mg can also be extracted from basalt; however, we will primarily focus our discussion on two enriched and accessible olivine deposits: the Semail ophiolite (Oman) and the Red Hills Ultramafic Complex (New Zealand) which conservatively contain 1.4 × 105 and 871 billion tonnes of olivine, respectively. “ – Scott et al (2021)
But Maungakura Red Hills near St Arnaud is part of the Mt Richman Forest Reserve; it’s surrounded by native ecosystems (Figs. 2 and 3).
References and further reading
- 2021: Scott et al; Transformation of abundant magnesium silicate minerals for enhanced CO2 sequestration, Nature Communications Earth & Environment 2 | 25
- 2020: UN Emissions Gap Report
- 2019: Kelemen et al; An Overview of the Status and Challenges of CO2 Storage in Minerals and Geological Formations, Frontiers in Climate 15 Nov.
- 2018: Harper et al; Land-use emissions play a critical role in land-based mitigation for Paris climate targets, Nature Communications 9, Article number: 2938
- Harper; Guest post on Carbon Brief explaining the research: Why BECCS might not produce ‘negative’ emissions after all
- 2018: National Geographic – This Gasoline Is Made of Carbon Sucked From the Air
- 2018: Dong et al; Effects of Elevated CO2 on Nutritional Quality of Vegetables: A Review, Frontiers in Plant Science, 15 August
- 2018: Gunnarsson, et al; The rapid and cost-effective capture and subsurface mineral storage of carbon and sulfur at the CarbFix2 site Int. J. Greenhouse Gas Control 79 pp117–126
- 2017: Hariharan & Mazzotti; Kinetics of flue gas CO2 mineralization processes using partially dehydroxylated lizardite, Chemical Engineering Journal 324, pp397-413
- 2015: Phelps et al; Modelling large-scale CO2 leakages in the North Sea, International Journal of Greenhouse Gas Control 38, pp221-220
- 2012: Smolker and Ernsting, BECCS (Bioenergy with Carbon Capture and Storage): Climate saviour or dangerous hype? Biofuel Watch UK.
IPCC Special Report Strengthening and implementing the global response, Global Warming of 1.5 ºC Chapter 4
- 1993: Habit of Bacterially Induced Precipitates of Calcium Carbonate: Examples from Laboratory Experiments and Recent Sediments, in Carbonate Microfabrics pp 105-116 and Chavetz et al;
- Carbfix (Iceland)
- Climeworks (Europe)
- Northern Lights Ltd (Norway)
- Carbon Engineering (Canada)
- Hot Lime Labs (New Zealand)
- Carbon Cure (US and Indonesia)
- Carbicrete (Canada)
- Blue Planet (US)
- Solidia (US)
- Biomason (US)