Carbon sequestration and storage (CSS), or the storage of carbon in minerals, soils, or organic matter, is not a new technology.
In the 1920s, it was used to scrub carbon dioxide from methane gas, removing the impure gas to increase the quality of the product.
Today, it forms the basis of a suite of technologies aimed at reducing the total carbon in our atmosphere and halting the domino effect of climate change.
But is it a vital and much needed solution or the cynical green washing of an ineffective technology pathway?
Proactive spoke with CSIRO senior research scientist and CO2 utilisation team leader Dr Dia Milani to get a clearer picture.
What is CCUS?
Carbon capture, utilisation and sequestration (CCUS) is the umbrella term for technologies and methodologies that capture carbon and convert, transform, or store it in non-gas forms.
Previously mostly used at large carbon sources like power plants, refineries and other industrial facilities, the technology is now being developed as a method of reducing total carbon in the atmosphere.
CCUS technology concerned with direct carbon capture involves passing carbon through solid sorbents or liquid solvents, that then absorb and combine with the carbon gas and are compressed into liquid or solid carbon.
“Like a household garbage, you can reduce, you can recycle to some extent, but you cannot stop people from producing waste,” said Dr Milani.
“Therefore, innovating technologies that can capture, reuse, recycle and effectively sequester this emissions are very important.
“CSIRO is working on a range of carbon capture technologies, but mostly focusing on liquid absorption and solid absorption-based technologies because of their scalability, reliability, and their high capture efficiency at an affordable and competitive costs.”
Beyond nature’s abilities
The concentration of carbon dioxide in Earth’s atmosphere is currently at nearly 412 parts per million (ppm) and rising.
That’s a 47% increase since the beginning of the Industrial Age (from about the 1800s onwards) and an 11% increase since 2000, just 23 years ago.
Carbon is a very stable element. Unlike nitrous oxide or hydrogen, it doesn’t react strongly in the atmosphere and combine into other elements – instead it sticks around.
For anywhere between 300 and 1,000 years.
Putting that in perspective, we’ve effectively doubled the amount of carbon in the atmosphere in just 200 years, and not a single iota of that generated carbon has left the atmosphere over that period.
Scientists know this increase is from human activity, rather than natural geological cycles, because burning fossil fuels produces a different ratio of carbon atoms as pollution, leaving a distinct fingerprint instruments can measure.
“There is a growing consensus among scientists and environmentalists,” Dr Milani explained, “That global greenhouse gas emissions have become sufficiently extensive that nature's resilience alone cannot absorb all the anthropogenically (human) produced greenhouse gas emissions in the coming decades.”
The oceans, soils and organics are the Earth’s carbon sink – the world’s forests absorb about 2.6 billion tonnes of carbon per year, and the soil and oceans have each absorbed about 25% (collectively about half) of our emitted carbon since the Industrial Revolution.
That’s no longer enough.
Racing against disaster
The IPCC warns that fossil fuel emissions must be halved within 11 years if global warming is to be limited to 1.5°C above pre-industrial levels.
Should warming of even 1.5°C occur, it’s predicted the result will be large-scale drought, famine, heat-stress, extinction events, and loss of habitable and arable land.
Effects will be most drastic in arid regions including the Middle East and the Sahel region in Africa, where fresh water is expected to dry up completely if warming reaches 2.0°C.
“Adopting effective emission reduction strategies is urgently required,” Dr Milani cautioned.
“The International Energy Agency has estimated that by 2050, carbon capture and storage, for short CCS technologies, will need to uptake six gigatons of CO2 per year.
“In the transition to renewable based economy, there is a profound global interest in stabilising atmospheric CO2 concentrations near or lower than the current levels until 2050.
“Therefore, a large portfolio of emission reduction technologies need to be considered where CCUS has a leading role in this consortium.”
Australia’s CCUS potential
As far as the CSIRO is concerned, Australia is ideally suited to leading the charge in carbon capture technology.
“Australia has developed land, a variety of mineral resources, a number of geological carbon dioxide storage sites, effective renewable energy options, and profound infrastructure and skill sets,” Dr Milani pointed out.
“The competitive advantage for Australia compared to other countries already exists. It's all about how the government can better support these initiatives and bridge the gap from reverie to reality.”
Perhaps ironically, one of Australia’s biggest advantages in the fight against carbonisation is the huge number of decommissioned mines and tailings sites on our shores.
One form of CCUS involves accelerating carbonation processes – that’s the tendency for carbon to store itself passively and naturally in decarbonated rock brought up from the Earth’s depths in mining and similar activities.
Accelerating that process could turn old Australian mine sites into huge carbon sinks.
“In terms of the scale and magnitude, mineral carbonation probably has the largest carbon sequestration potential in Australia and also over the world,” Dr Milani emphasised.
The CSIRO isn’t expecting companies and stakeholders to pursue these new technologies out of the goodness of their hearts, however.
“The mining industry is responsible for 6.2% of Australia's energy demand and 9.5% of greenhouse gas emissions as in 2019, excluding emissions related to the offshore commodities processing,” Dr Milani said.
“Mining companies are required to fulfill their corporate social responsibility and the social licence to operate as part of mining culture and the existing regulatory framework.
“Supporting Accelerated Mineral Carbonation (AMC) technologies not only helps in reducing their own emissions, but also potentially create new carbon products and markets that can offset the cost and bring incentives to these companies.”
A CCUS product market
The CSIRO envisions an entirely new CCUS product market forming as carbon capture technologies take off.
“In addition to carbon capture and storage purposes, the recovery and production of valuable end products such as silica, magnesium and calcium carbonates, iron oxide and other metals in sufficiently pure form would bring many economic benefits and create new markets,” Dr Milani explained.
In other words, CCUS technologies have potential to not only remove carbon from the atmosphere and reduce a company’s emissions, but could also form an entirely new revenue stream, offering valuable by-products that could pay for the technology and incentivise its use.
The CO2 itself can also be converted into useful products, including everything from alcohols and electro-fuels, to plastics, concrete, and reactants for chemical synthesis.
While each mine site would require a different mix of technologies, methodologies and supply chains to achieve the CSIRO’s vision, the result could be a net positive in every way: environmentally, economically and socially.
So, how do we get there?
Turning reverie into reality
“In my opinion, we need three drivers to work together to roll out a successful business model,” Dr Milani proposed.
“The first of the three drivers is fundamental and applied research, development and design that is usually fostered by universities and research institutes.
“Second is the policy and stimulus program developed by the government.
“Third is the corporate leadership for early adoption.
“These three drivers need to work together to develop a roadmap with a clear objectives and short, medium, and long term to bring this to reality.
“The government should examine their regulatory frameworks for mining operators or mining operations, seeking ways to improve or to provide incentives for an accelerated mineral carbonation technologies, as well as streamlining permitting processes, while advocating for public health and safety.
“It will need well defined regulatory frameworks with a clear vision in short, medium and long term, workforce investment opportunities and an early-stage adoption environment for the value sector, such as finance, mining, manufacturing, insurance, small businesses, and others to come in and play their roles.”
Major companies like Origin Energy (often partnered with small caps like Elixir Energy Ltd (ASX:EXR)) and BHP (ASX:BHP) are already exploring the potential of these technologies on their mine sites, but more is needed.
While the road ahead is unlikely to be smooth or short, a concerted effort by government, the resources industry, and other sectors of society and the value chain has every possibility of charting a path to a safe, economically stable, decarbonised future.