Tag: decarbonisation

What are negative emissions?

Negative emissions

What are negative emissions?

In order to meet the long-term climate goals laid out in the Paris Agreement, there is a need to not only reduce the emission of harmful greenhouse gases into the air, but actively work to remove the excess carbon dioxide (CO2) currently in the atmosphere, and the CO2 that will continue to be emitted as economies work to decarbonise.

The process of greenhouse gas removal (GGR) or CO2 removal (CDR) from the atmosphere is possible through negative emissions, where more CO2 is taken out than is being put into the atmosphere. Negative emissions can be achieved through a range of nature-based solutions or through man-made technologies designed to remove CO2 at scale.

What nature-based solutions exist to remove CO2 from the atmosphere?

One millennia-old way of achieving negative emissions is forests. Trees absorb carbon when they grow, either converting this to energy and releasing oxygen, or storing it over their lifetime. This makes forests important tools in limiting and potentially reducing the amount of CO2 in the atmosphere. Planting new forests and regenerating forests has a positive effect on the health of the world as a result.

However, this can also go beyond forests on land. Vegetation underwater has the ability to absorb and store CO2, and seagrasses can in fact store up to twice as much carbon as forests on land – an approach to negative emissions called ‘blue carbon’.

Key negative emissions facts

 

Did you know?

Bhutan is the only carbon negative country in the world – its thick forests absorb three times the amount of CO2 the small country emits.

What man-made technologies can deliver negative emissions?

Many scientists and experts agree one of the most promising technologies to achieve negative emissions is bioenergy with carbon capture and storage (BECCS). This approach uses biomass – sourced from sustainably managed forests – to generate electricity. As the forests used to create biomass absorb CO2 while growing, the CO2 released when it is used as fuel is already accounted for, making the whole process low carbon.

By then capturing and storing any CO2 emitted (often in safe underground deposits), the process of electricity generation becomes carbon negative, as more carbon has been removed from the atmosphere than has been added.

Direct air carbon capture and storage (DACCS) is an alternative technological solution in which CO2 is captured directly from the air and then transported to be stored or used. While this could hold huge potential, the technology is currently in its infancy, and requires substantial investment to make it a more widespread practice.

The process of removing CO2 from the atmosphere is known as negative emissions, because more CO2 is being taken out of the atmosphere than added into it.

How much negative emissions are needed?

According to the Intergovernmental Panel on Climate Change, negative emissions technologies could be required to capture 20 billion tonnes of carbon annually to help prevent catastrophic changes in the climate between now and 2050.

Negative emissions fast facts

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What is carbon capture usage and storage?

Carbon capture

What is carbon capture usage and storage?

Carbon capture and storage (CCS) is the process of trapping or collecting carbon emissions from a large-scale source – for example, a power station or factory – and then permanently storing them.

Carbon capture usage and storage (CCUS) is where captured carbon dioxide (CO2) may be used, rather than stored, in other industrial processes or even in the manufacture of consumer products.

How is carbon captured?

Carbon can be captured either pre-combustion, where it is removed from fuels that emit carbon before the fuel is used, or post-combustion, where carbon is captured directly from the gases emitted once a fuel is burned.

Pre-combustion carbon capture involves solid fossil fuels being converted into a mixture of hydrogen and carbon dioxide under heat pressure. The separated CO2 is

captured and transported to be stored or used.

Post-combustion carbon capture uses the addition of other materials (such as solvents) to separate the carbon from flue gases produced as a result of the fuel being burned. The isolated carbon is then transported (normally via pipeline) to be stored permanently –  usually deep underground – or used for other purposes.

Carbon capture and storage traps and removes carbon dioxide from large sources and most of that CO2 is not released into the atmosphere.

 What can the carbon be used for?

Once carbon is captured it can be stored permanently or used in a variety of different ways. For example, material including carbon nanofibres and bioplastics can be produced from captured carbon and used in products such as airplanes and bicycles, while several start-ups are developing methods of turning captured CO2 into animal feed.

Captured carbon can even assist in the large-scale production of hydrogen, which could be used as a carbon-neutral source of transport fuel or as an alternative to natural gas in power generation.

Key carbon capture facts

Where can carbon be stored?

Carbon can be stored in geological reserves, commonly naturally occurring underground rock formations such as unused natural gas reservoirs, saline aquifers, or ‘unmineable’ coal beds. The process of storage is referred to as sequestration.

The underground storage process means that the carbon can integrate into the earth through mineral storage, where the gas chemically reacts with the minerals in the rock formations and forms new, solid minerals that ensure it is permanently and safely stored.

Carbon injected into a saline aquifer dissolves into the water and descends to the bottom of the aquifer in a process called dissolution storage.

According to the Global CCS Institute, over 25 million tonnes of carbon captured from the power and industrial sectors was successfully and permanently stored in 2019 across sites in the USA, Norway and Brazil. 

What are the benefits of carbon storage?

CO2 is a greenhouse gas, which traps heat in our atmosphere, and therefore contributes to global warming. By capturing and storing carbon, it is being taken out of the atmosphere, which reduces greenhouse gas levels and helps mitigate the effects of climate change.

Carbon capture fast facts

  • CCUS is an affordable way to lower CO2 emissions – fighting climate change would cost 70% more without carbon capture technologies
  • The largest carbon capture facility in the world is the Petra Nova plant in Texas, which has captured a total of 5 million tonnes of CO2, since opening in 2016
  • Drax Power Station is trialling Europe’s biggest bioenergy carbon capture usage and storage project (BECCS), which could remove and capture more than 16 million tonnes of CO2 a year by the mid 2030s, delivering a huge amount of the negative emissions the UK needs to meet net zero

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What is climate change?

Climate change

What is climate change?

Climate change refers to the change in weather patterns and global temperature of the earth over long periods of time. In a modern context, climate change describes the rise of global temperatures that has been occurring since the Industrial Revolution in the 1800s.

What causes climate change?

While there have been natural fluctuations in the earth’s climate over previous millennia, scientists have found that current-day temperatures are rising quicker than ever due to the excessive amount of carbon dioxide (CO2) and other greenhouse gasses being released into the atmosphere.

Key climate crisis facts

An excess of CO2 in the atmosphere accentuates something called the ‘greenhouse effect’. As CO2 traps heat in the earth’s atmosphere, it warms the planet and causes a rise in average global temperature. International efforts, such as the Paris Climate Accords, are dedicated to ensuring temperatures do not rise 2 degrees Celsius above pre-industrial levels, which could lead to catastrophic conditions on the planet.

In the modern context, climate change describes the rise of global temperatures occurring since the Industrial Revolution in the 1800s.

How do humans contribute to climate change?  

Industries such as transport, agriculture, energy and manufacturing have traditionally relied on the use of coal, oil and other fossil fuels. These fuels, when combusted or used, emit large amounts of CO2 into the atmosphere, further advancing the greenhouse effect and contributing to climate change.

Human reliance and consumption of these products mean today CO2 levels are the highest they’ve been in 800,000 years.

Why are rising temperatures harmful to the planet?

Our planet has a history of experiencing periods of extreme weather conditions – for example the last Ice Age, which finished 12,000 years ago. However, the rapid rise in temperatures seen today is harmful because a hotter planet completely affects our natural environment.

A steep rise in global temperature can melt ice sheets and cause higher sea levels which can, in turn, contribute to more extreme storms and even threaten entire islands and coastal communities. As the planet warms, extreme weather events, such as bushfires could become more common, which can destroy homes, impact agriculture and degrade air quality, while entire ecosystems, habitats and animal and insect species could also be threatened by climate change. 

What can be done to mitigate the effects of climate change?

Reducing CO2 emissions is a key way of slowing down the pace of climate change. To do so, industries across the global economy must decarbonise to become less dependent on fossil fuels, such as coal and petrol, and adopt new lower carbon energy sources.

Decarbonisation will rely on a number of factors, including a technological response that sees the development and implementation of carbon neutral and carbon negative ways of creating heat, electricity and fuels, including the use of innovations such as carbon capture and storage (CCS).

There is also a need for a policy and governmental response that promotes investment in new cleaner technologies and disincentivises dirtier industries through mechanisms like the carbon tax. Countries and economies will need to work collaboratively to achieve common, climate-oriented goals that will also enable smaller scale action to be taken by individuals around the world. 

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What is decarbonisation?

Decarbonisation

What is decarbonisation?

Decarbonisation is the term used for the process of removing or reducing the carbon dioxide (CO2) output of a country’s economy. This is usually done by decreasing the amount of CO2 emitted across the active industries within that economy. 

Why is decarbonisation important?

Currently, a wide range of sectors – industrial, residential and transport – run largely on fossil fuels, which means that their energy comes from the combustion of fuels like coal, oil or gas.

The CO2 emitted from using these fuels acts as a greenhouse gas, trapping in heat and contributing to global warming. By using alternative sources of energy, industries can reduce the amount of CO2 emitted into the atmosphere and can help to slow the effects of climate change.

Key decarbonisation facts

Why target carbon dioxide?

 There are numerous greenhouse gases that contribute to global warming, however CO2 is the most prevalent. As of 2018, carbon levels are the highest they’ve been in 800,000 years.

The Paris Agreement was created to hold nations accountable in their efforts to decrease carbon emissions, with the central goal of ensuring that temperatures don’t rise 2 degrees Celsius above pre-industrial level.

With 195 current signatories, economies have begun to factor in the need for less investment in carbon, with the UK leading the G20 nations in decarbonising its economy in the 21st century.

How is decarbonisation carried out?

There are numerous energy technologies that aim to reduce emissions from industries, as well as those that work towards reducing carbon emissions from the atmosphere.

Decarbonisation has had the most progress in electricity generation because of the growth of renewable sources of power, such as wind turbines, solar panels and coal-to-biomass upgrades, meaning that homes and businesses don’t have to rely on fossil fuels. Other innovations, such as using batteries and allowing homes to generate and share their own power, can also lead to higher rates of decarbonisation. As the electricity itself is made cleaner, it therefore assists electricity users themselves to become cleaner in the process.

Other approaches, such as reforestation or carbon capture and storage, help to pull existing carbon from the air, to neutralise carbon output, or in some cases, help to make electricity generation – and even entire nations – carbon negative.

Alternative power options means that homes and businesses don’t have to rely on traditional carbon fuels.

What is the future of decarbonisation?

For decarbonisation to be more widely adopted as a method for combating climate change, there needs to be structural economical change, according to Deloitte Access Economics. Creating more room for decarbonisation through investing in alternative energies means that “there are a multitude of job-rich, shovel-ready, stimulus opportunities that also unlock long-term value”.

 Decarbonisation fast facts

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Button: What is biomass?

 

Plant more forests and better manage them

Working forests in the US South

There is an ongoing debate about forests’ contribution to fighting the climate crisis.

Forests can act as substantial and effective tools for carbon sequestration during a high growth phase. They can also function as significant and extensive carbon storage areas during maturity and throughout multiple stages of the age class cycle, if managed effectively at a landscape level. Or, they can be emitters of carbon if over-harvested, subject to fire, storm, pest or disease damage.

Different age class forest stands in Louisiana

In a natural state, forests will go through each of these life phases: rapid early growth; maturity and senescence; damage, decay and destruction through natural causes. Then they begin the cycle again, absorbing and then emitting carbon dioxide (CO2) in a continual succession.

Recently, loud voices have argued against forest management per se; against harvesting for wood products in particular, suggesting that this reduces both forest carbon stocks and sequestration capacity.

Pine cut in into wood for different wood products markets in Louisiana. Big, thick, straight higher value sections go to sawmills and smaller and misshapen low-grade wood not suitable for timber production is sold to pulp, paper or wood pellet mills.

Many foresters consider that this is just not correct. In fact, the opposite is true. Research and evidence clearly support the foresters’ view. Active forest management, when carried out appropriately, actually increases the amount of carbon sequestered, ensures that carbon is stored in solid wood products, and provides substantial savings of fossil fuels by displacing other high carbon materials (e.g. concrete, steel, brick, plastic and coal).

Oliver et al.(2014)[1] compared the impact of forest harvesting and the use of wood products to substitute other high-carbon materials, concluding that: ‘More CO2 can be sequestered synergistically in the products or wood energy and landscape together than in the unharvested landscape. Harvesting sustainably at an optimum stand age will sequester more carbon in the combined products, wood energy, and forest than harvesting sustainably at other ages.’

This research demonstrated that an increase in the use of structural timber to displace concrete and steel could lead to substantial emissions savings compared to unharvested forest. The use of wood for energy is an essential component of this displacement process, although it is important to use appropriate feedstocks. Burning wood that could be used for structural timber will not lead to a positive climate impact.

The message here is to manage working forests for optimum sawlog production for long-life solid wood products and utilise the by-products for energy where this is the most viable market, this provides the best all-round climate benefit.

What happens when you close the gate

Closing the forest gate and stopping all harvesting and management is one option being championed by some climate change campaigners. There is certainly a vital role for the preservation and protection of forests globally: primary and virgin forests, intact landscapes, high biodiversity and high conservation value areas all need to be protected.

That doesn’t necessarily mean that there is no forest management. It should mean careful and appropriate management to maintain and ensure the future of the resource. In these cases, management is with an objective to reduce the risk of fire, pests and disease, rather than for timber production.

Globally, we need better governance, understanding and implementation of best practice to achieve this. Forest certification and timber tracing systems are a good start. This can equally apply to the many hundreds of millions of hectares of ‘working forest’ that do not fall into the protection categories; forests that have been managed for many hundreds of years for timber production and other purposes. Harvesting in these forests can be more active, but governance, controls and the development of best practice are required. Better management not less management.

During the 1970s there was a significant change of policy in the US, aimed at removing massive areas of publicly owned forest from active management – effectively closing the gate. The drivers behind this policy were well meaning; it was intended to protect and preserve the habitat of endangered species, but the unintended consequences have also had a substantial impact. In the 1970s little thought was given to the carbon sequestration and storage potential of forests and climate change was not at the top of the agenda.

The west coast of the US was most substantially affected by these changes, more than in the US South, but the data below looks at the example of Mississippi which is primarily ‘working forest’ and 88% in private ownership.

Pine trees in Mississippi working forest

This is the location of Drax’s Amite pellet mill. The charts below show an interesting comparison of forest ownership in Mississippi where limited or no harvesting takes place and where active management for timber production occurs. In the short term the total volume of timber stored per hectare is higher where no harvesting occurs. This makes sense since the forest will keep growing until it reaches its climax point and succumbs to fire, pest or disease.

Average standing volume per unit area in the private sector, where active management occurs, is the lowest as timber is periodically removed for use in solid wood products. Remember that the Oliver et al. analysis (which does not include re-growth), showed that despite a short-term reduction in forest carbon, the total displacement of high-carbon materials with wood for structural timber and energy leads to a far higher emissions saving. It is better to have a lower stock of carbon in a working forest and to be continually sequestering new carbon for storage in solid wood products.

Average standing volume per acre by ownership class, Mississippi[2]

Comparing the average annual growth rates across all forest types in Mississippi, annual growth in the private sector is almost double that in the unharvested public forest. This differential is increased even further if only commercial species like pine are considered and a comparison is made between planted, well managed forests and those that are left to naturally regenerate.

Average growth rates per acre by ownership class, Mississippi[3]

The managed forest area is continually growing and storing more carbon at a materially higher rate than less actively managed forest. As harvesting removes some forest carbon, these products displace high carbon materials in construction and energy and new young forests are replacing the old ones.

We know that forests are not being ‘lost’ and that the overall storage of carbon is increasing. For example, the Drax catchment area analysis for the Amite biomass wood pellet plant showed an increase in forest area of 5,200 ha and an increase in volume of 11 million m3 – just in the area around the pellet mill. But what happens to protected forest area, the forest reserve with limited or no harvesting?

Over the last 20 years the average annual loss of forest to wildfire in the US has been 2.78 million ha per year (the same as the UK’s total area of productive forest). According to the USFS FIA database the average standing volume of forests in the US is 145 m3 per ha (although in the National Park land this is 365 m3 per ha). Therefore, wildfires are responsible for the average annual combustion of 403 million m3 of wood p.a. (equal to the total annual wood harvest of the US) or 2.5 billion m3 if entirely in National Parks.

One cubic metre equates to a similar quantity of CO2 released into the atmosphere each year, therefore wildfires are responsible for between 407 million and 2.5 billion tonnes of CO2 emissions in the US each year[4].

Wildfires in the US

Starrs et al. (2018)[5] demonstrated that the risk of wildfire was significantly higher in federally owned reserved forest (where harvesting and management were restricted), compared to privately owned forests with active management.

In California, the risk of wildfire in federal forest (2000-15) was almost double the risk in private forests where both had State firefighting resources. The risk of fires in federal lands had increased by 93% since 1950-66, compared to only 33% in non-federal forests, due to the change in forest management practice in the 1970s.

Forest fire in California

Closing the gate means that the carbon stock is maintained and grows in the short term, but there is no opportunity for carbon to be stored in solid wood products, no high-carbon materials are displaced (concrete, steel and fossil fuels) and the rate of sequestration declines as the forest ages. Eventually the forest will reach its natural climax and die, releasing all of that carbon back into the atmosphere. The managed forest, by contrast, will have a lower standing volume at a certain point in time, but will be in a continual cycle of sequestration, storage and regrowth – with a much lower risk of fire and disease. If managed correctly, the rate of growth and standing volume will also increase over time.

How should we manage the forest

Forests are extremely variable, there are a vast variety of tree species, soil, geological features, water regimes, temperature, climate and many other factors that combine to make unique ecosystems and forest landscapes. Some of these are rare and valuable for the exceptional assemblages they contain, some are commonplace and widespread. Some are natural, some man-made or influenced by human activity.

Forests have many important roles to play and careful management is required. In some cases that management may be protection, preservation and monitoring. In other cases, it may be active harvesting and planting to optimise growth and carbon storage.

Cypress forests in the Atchafalaya Basin in Louisiana are an example of a forest landscape where the suitable management practice is protection, preservation and monitoring

For each forest type and area, we need to recognise the highest or best purpose(s) for that land in the objectives set and carefully plan the management to optimise and sustain that value. The primary value could be in species and habitat diversity or rarity; provision of recreation and aesthetic value; production of timber, forest products and revenue generation; carbon sequestration and storage; water management and other ecosystem benefits.

Most likely it will be a combination of several of these benefits. Therefore, best management practice usually involves optimising each piece of forest land to provide the most effective combination of values. Forests can deliver many benefits if we are sensible about how we manage them.

In a recent study Favero et al. (2020)[6] concluded that: Increased bioenergy demand increases forest carbon stocks thanks to afforestation activities and more intensive management relative to a no-bioenergy case. Some natural forests, however, are converted to more intensive management, with potential biodiversity losses…the expanded use of wood for bioenergy will result in net carbon benefits, but an efficient policy also needs to regulate forest carbon sequestration.

[1] CHADWICK DEARING OLIVER, NEDAL T. NASSAR, BRUCE R. LIPPKE, and JAMES B. McCARTER, 2014. Carbon, Fossil Fuel, and Biodiversity Mitigation with Wood and Forests.
[2] US Forest Service, FIA Database, 2020.
[3] US Forest Service, FIA Database, 2020.
[4] Assumes an average basic density of 570kg/m3 and 50:25:25 ratio of cellulose, lignin and hemicellulose.
[5] Carlin Frances Starrs, Van Butsic, Connor Stephens and William Stewart, 2018. The impact of land ownership, firefighting, and reserve status on fire probability in California.
[6] Alice Favero, Adam Daigneault, Brent Sohngen, 2020. Forests: Carbon sequestration, biomass energy, or both?

Is renewable-rich the new oil-rich?

Aerial view of hundreds solar energy modules or panels rows along the dry lands at Atacama Desert, Chile. Huge Photovoltaic PV Plant in the middle of the desert from an aerial drone point of view

We’re all familiar with the phrase ‘oil-rich’ nations, but as low carbon energy sources become ever more important to meeting global demand, renewable energy could become a global export. With a future favouring zero-carbon and even negative emissions innovation, here are some countries that are not only harnessing their natural resources to make more renewable energy, but are making progress in storing and exporting it.

Could these new opportunities lead us to one day deem them ‘renewable-rich’?

Could Europe import its solar power supply?

With the largest concentrated solar farm in the world, Morocco is already streets ahead in its ability to capture and convert sunlight into power. The 3,000 hectare solar complex, known as Noor-Ouarzazate, has a capacity of 580 megawatts (MW), which provides enough power for a city twice the size of Marrakesh.

Noor-Ouarzazate Power Plant, Morocco. Image source: ACWA Power

Its uses curved mirrors to direct sunlight into a singular beam that creates enough heat to melt salt in a central tower. This stores the heat and – when needed – is used to create steam which spins a turbine and generates electricity. This has helped keep Morocco on course to achieve its goal of deriving 42% of its power from renewable sources by the end of 2020, which potentially means a surplus in the coming years.

Morocco already has 1.4 gigawatts (GW) of interconnection with Spain, and another 700 MW is scheduled to come online before 2026. The country’s close proximity to Europe could make its solar capacity a source of power across the continent.

Africa’s geothermal potential

Olkaria II geothermal power plant in Kenya

Kenya was the first African nation to embrace geothermal energy and has now been using it for decades. In 1985, Kenya’s geothermal generation produced 45 MW of power – 30 years later, the country now turns over 630 MW.

Kenya’s ample generation of geothermal electricity is due to an abundance of steam energy in the underground volcanic wells of Olkaria, in the Great Rift Valley. In 2015, the region was responsible for providing 47% of the country’s power.

Currently the Olkaria region is thought to have a potential capacity of 2 GW of power, which could help to provide a source of clean energy for Kenya’s neighbours. However, there is potential for the rest of East Africa to generate its own geothermal power.

In this region of the continent there is an estimated 20 GW of power generation capacity possible  from stored geothermal energy, while the demand for the creation of usable grids that can connect multiple countries is high. Kenya is currently expanding its own grid, installing a planned 3,600 miles of new electrical wiring across the country.

Winds of change

China’s position in the renewable energy market is already up top, with continuous investment in solar and hydro power giving it a renewable capacity of more than 700 GW

The country is also home to the world’s largest onshore wind farm, in the form of the Gansu Wind Farm Project, which is made up of over 7,000 turbines. It is set to have a capacity of 20 GW by the end of 2020, bringing the nationwide installed wind capacity to 250 GW.

With China exporting more than 20,000 gigawatt-hours (GWh) of electricity in 2018, large scale renewable projects can have a wide-reaching effect beyond its borders. South-Asia is the primary market, but excesses of power in Western China have stoked ideas of exporting power as far away as Germany.

Can the US store the world’s carbon?

In the quest for zero-carbon energy it won’t just be nations that can export excess energy that could stand to profit – those that can import emissions could also benefit.

While many countries are developing the capabilities to capture carbon dioxide (CO2), storing it safely and permanently is another question. Having underground facilities that can store CO2 creates an opportunity to import and sequester carbon as a service for other nations. Norway is already doing it, but the US has the greatest potential thanks to its abundance of large underground storage capabilities.

The Global CCS Institute highlights the US as the country most prepared to deploy carbon capture and storage (CCS) at scale, thanks to its vast landscape, history of injecting CO2 in enhanced oil recovery, and favourable government policies.

The Petra Nova plant in Texas is also known as the world’s largest carbon capture facility. The coal-power station captured more than 1 million tonnes of CO2 within the first 10 months of operating as a 654 MW unit.

Carbon capture facility at the Petra Nova coal-fired power plant, Texas, USA

Chile’s hydrogen innovation

Hydrogen is becoming increasingly relevant as an energy source thanks to its ability to generate electricity and power transport while releasing far fewer emissions than other fossil fuels.

Chile was an early proponent of energy sharing with its hydrogen programme. The country uses solar electricity generated in the Atacama Desert (which sees 3,000 hours of sunlight a year), to power hydrogen production in a process called electrolysis, which uses electricity to split water into oxygen and hydrogen.

Chile plans to export the gas to Japan and South Korea, but with global demand for hydrogen set to grow, higher-volume, further-reaching exporting of the country’s hydrogen could soon be on the way.

Going forward, these green innovations – from carbon storage to geothermal potential – could increasingly be shared between countries and continents in an attempt to lower the overall carbon footprint of the world’s energy. This could create a global power shift toward nations which, rather than having high capacity for fossil fuel extraction, can instead use a different set of natural resources to generate, store and export cleaner energy.

How do you store CO2 and what happens to it when you do?

Sunrise over Saltwick Bay, Whitby, North Yorkshire

The North Sea has long shaped British trade. It’s also been instrumental in how the country is powered, historically providing an abundant source of oil and natural gas. However, this cold fringe off the North Atlantic could also play a vital role in decarbonising the UK’s economy – not because of its full oil and gas reservoirs, but thanks to its empty ones.

In an effort to limit or reduce the amount of carbon dioxide (CO2) in the atmosphere, countries around the world are rushing towards large scale carbon capture usage and storage projects (CCUS). In this process, CO2 is captured from sources, such as energy production and manufacturing, or directly removed from the air, and reused or stored permanently – for example, underground in disused oil and gas reservoirs or other suitable geological formations.

CCUS transport overview graphic

Source: CCS Image Library, Global CCS Institute [Click to view/download]

The International Energy Agency estimates that 100 billion tonnes of CO2 must be stored by 2060 to limit temperature rise to 2 degrees Celsius. Yet the Global CCS Institute reports that, as of 2019, the projects currently in operation or under construction had the capacity to capture and store only 40 million tonnes of CO2 per year.

It’s clear the global capacity for CCUS must accelerate rapidly in the coming decade, but it raises the questions: where can these millions of tonnes of CO2 be stored, and what happens to it once it is?

Where can you store CO2?

The most well-developed approach to storing CO2 is injecting it underground into naturally occurring, porous rock formations such as former natural gas or oil reservoirs, coal beds that can’t be mined, or saline aquifers. These are deep geological formations with deposits of very salty water present in the rock’s pores and most commonly found under the ocean. The North Sea and the area off the US Gulf Coast contain several saline aquifers.

Once CO2 has been captured using CCUS technology, it’s pressurised and turned into a liquid-like form known as ‘supercritical CO2’. From there it’s transported via pipeline and injected into the rocks found in the formations deep below the earth’s surface. This is a process called geological sequestration.

CCUS storage overview graphic

Source: CCS Image Library, Global CCS Institute [Click to view/download]

But while pumping CO2 into the ground is one thing, ensuring it stays there and isn’t released into the atmosphere is another. Fortunately, there are several ways to ensure CO2 is stored safely and securely.

Keeping the lid on CO2 stored underground

Put simply, the most straightforward way underground reservoirs store CO2 is through the solid impermeable rock that typically surrounds them. Once CO2 is injected into a reservoir, it slowly moves upwards through the reservoir until it meets this layer of impermeable rock, which acts like a lid the CO2 cannot pass through. This is what’s referred to as ‘structural storage’ and is the same mechanism that has kept oil and gas locked underground for millions of years.

White chalk stone

White chalk stone

Over time, the CO2 trapped in reservoirs will often begin to chemically react with the minerals of the surrounding rock. The elements bind to create solid, chalky minerals, essentially locking the CO2 into the rock in a process called ‘mineral storage’.

In the case of saline aquifers, as well as structural and mineral storage, the CO2 can dissolve into the salty water in a process called ‘dissolution storage’. Here, the dissolved CO2 slowly descends to the bottom of the aquifer.

In any given reservoir, each (or all) of these processes work to store CO2 indefinitely. And while there remains some possibility of CO2 leakage from a site, research suggests it will be minimal. One study, published in the journal Nature, suggests more than 98% of injected CO2 will remain stored for over 10,000 years.

Storage for the net zero future

In the United States, industrial scale storage is in action in Texas, Wyoming, Oklahoma and Illinois, and there are projects in progress across the United Arab Emirates, Australia, Algeria and Canada. However, there is still a long way to go for CCUS to reach the scale it needed to limit the effects of climate change.

Research has shown that globally, there is an abundance of CO2 storage sites, which could support widespread CCUS adoption. A report compiled by researchers at Imperial College London and E4tech and published by Drax details an estimated 70 billion tonnes of storage capacity in the UK alone. The US, on the other hand, has an estimated storage capacity of 10 trillion tonnes.

It’s clear the capacity for storage is present, it now remains the task of governments and companies to ramp up CCUS projects to begin to reach the scale necessary.  

In the UK, Drax Power Station is piloting bioenergy carbon capture and storage projects (BECCS), which could see it becoming the world’s first negative emissions power station. As part of the Zero Carbon Humber partnership, it could also form a part of the world’s first zero carbon industrial hub in the north of the UK.

Such projects are indicative of the big ambitions CCUS technology could realise – not just decarbonising single sites, but capturing and storing CO2 from entire industries and regions. There is still a way to go to meet that ambition, but it is clear the resources and knowledge necessary to get there are ready to be utilised.

Zero Carbon Humber

Source: Zero Carbon Humber [Click to view/download]

Learn more about carbon capture, usage and storage in our series:

From steel to soil – how industries are capturing carbon

Construction metallic bars in a row

Carbon capture, use and storage (CCUS) is a vital technology in the energy industry, with facilities already in place all over the world aiming to eliminate carbon dioxide (CO2) emissions.

However, for decarbonisation to go far enough to keep global warming below 2oC – as per the Paris Climate Agreement – emission reductions are needed throughout the global economy.

From cement factories to farmland, CCUS technology is beginning to be deployed in a wide variety of sectors around the world.

Construction

The global population is increasingly urban and by 2050 it’s estimated 68% of all people will live in cities. For cities to grow sustainably, it’s crucial the environmental impact of the construction industry is reduced.

Construction currently accounts for 11% of all global carbon emissions. This includes emissions from the actual construction work, such as from vehicle exhaust pipes, but a more difficult challenge is reducing embedded emissions from the production of construction materials.

Steel and concrete are emissions-heavy to make; they require intense heat and use processes that produce further emissions. Deploying widespread CCUS in the production of these two materials holds the key to drastically reducing carbon emissions from the built environment.

Steel manufacturing alone, regardless of the electricity used to power production, is responsible for about 7% of global emissions. Projects aimed at reducing the levels of carbon released in production are planned in Europe and are already in motion in the United Arab Emirates.

Abu Dhabi National Oil Company and Masdar, a renewable energy and sustainability company, formed a joint venture in 2013 with the aim of developing commercial-scale CCUS projects.

In its project with Emirates Steel, which began in 2016, about 800,000 tonnes of CO2 is captured a year from the steel manufacturing plant. This is sequestered and used in enhanced oil recovery (EOR). The commercially self-sustaining nature of this project has led to investigation into multiple future industrial-scale projects in the region.

Cement manufacturing, a process that produces as much as 8% of global greenhouse gases, is also experiencing the growth of innovative CCUS projects.

Pouring ready-mixed concrete after placing steel reinforcement to make the road by mixing in construction site

Norcem Cement plant in Brevik, Norway has already begun experimenting with CCUS, calculating that it could capture 400,000 tonnes of CO2 per year and store it under the North Sea. If the project wins government approval, Norcem could commence operations as soon as 2023.

However, as well as reducing emissions from traditional cement manufacturing and the electricity sources that power it, a team at Massachusetts Institute of Technology is exploring a new method of cement production that is more CCUS friendly.

By pre-treating the limestone used in cement creation with an electrochemical process, the CO2 produced is released in a pure, concentrated stream that can be more easily captured and sequestered underground or harnessed for products, such as fizzy drinks.

Agriculture

It’s hard to overstate the importance of the agriculture industry. As well as feeding the world, it employs a third of it.

Within this sector, fertiliser plays an essential role in maintaining the global food supply. However, the fertiliser production industry represents approximately 2% of global CO2 emissions.

CCUS technology can reduce the CO2 contributions made by the manufacturing of fertiliser, while maintaining crop reliability. In 2019, Oil and Gas Climate Initiative’s (OGCI) Climate Investments announced funding for what is expected to be the biggest CCUS project in the US.

Tractor with pesticide fungicide insecticide sprayer on farm land top view Spraying with pesticides and herbicides crops

Based at the Wabash Valley Resources fertiliser plant in Indiana, the project will capture between 1.3 and 1.6 million tonnes of CO2 from the ammonia producer per year. The captured carbon will then be stored 2,000 metres below ground in a saline aquifer.

Similarly, since the turn of the millennium Mitsubishi Heavy Industries Engineering has deployed CCUS technology at fertiliser plants around Asia. CO2 is captured from natural gas pre-combustion, and used to create the urea fertiliser.

However, the agriculture industry can also capture carbon in more nature-based and cheaper ways.

Soil acts as a carbon sink, capturing and locking in the carbon from plants and grasses that die and decay into it. However, intensive ploughing can damage the soil’s ability to retain CO2.

It only takes slight adjustments in farming techniques, like minimising soil disturbance, or crop and grazing rotations, to enable soil and grasslands to sequester greater levels of CO2 and even make farms carbon negative.

Transport

The transport sector is the fastest growing contributor to climate emissions, according to the World Health Organisation. Electric vehicles and hydrogen fuels are expected to serve as the driving force for much of the sector’s decarbonisation, however, at present these technologies are only really making an impact on roads. There are other essential modes of transport where CCUS has a role to play. 

Climeworks, a Swiss company developing units that capture CO2 directly from the air, has begun working with Rotterdam The Hague Airport to develop a direct air capture (DAC) unit on the airport’s grounds.

Climeworks Plant technology [Source: Climeworks Photo by Julia Dunlop]

hydrogen filling station in the Hamburg harbor city

Hydrogen filling station in Hamburg, Germany.

However, beyond just capturing CO2 from planes taking off, Climeworks aims to use the CO2 to produce a synthetic jet fuel – creating a cycle of carbon reusage that ensures none is emitted into the atmosphere. A pilot project aims to create 1,000 litres of the fuel per day in 2021.

Another approach to zero-carbon transport fuel is the utilisation of hydrogen, which is already powering cars, trains, buses and even spacecraft.

Hydrogen can be produced in a number of ways, but it’s predominantly created from natural gas, through a process in which CO2 is a by-product. CCUS can play an important role here in capturing the CO2 and storing it, preventing it entering the atmosphere.

The hydrogen-powered vehicles then only emit water vapour and heat.

From every industry to every business to everyone

As CCUS technology continues to be deployed at scale and made increasingly affordable, it has the potential to go beyond just large industrial sites, to entire economic regions.

Global Thermostat is developing DAC technology which can be fitted to any factory or plant that produces heat in its processes. The system uses the waste heat to power a DAC unit, either from a particular source or from the surrounding atmosphere. Such technologies along with those already in action like bioenergy with carbon capture and storage (BECCS), can quickly make negative emissions a reality at scale.

However, to capture, transport and permanently store CO2 at the scale needed to reach net zero, collaboration partnerships and shared infrastructure between businesses in industrial regions is essential.

The UK’s Humber region is an example of an industrial cluster where a large number of high-carbon industrial sites sit in close proximity to one another. By installing BECCS and CCUS infrastructure that can be utilised by multiple industries, the UK can have a far greater impact on emissions levels than through individual, small-scale CCUS projects.

Decarbonising the UK and the world will not be achieved by individual sites and industries but by collective action that transcends sectors, regions and supply chains. Implementing CCUS at as large a scale as possible takes a greater stride towards bringing the wider economy and society to net zero.

Learn more about carbon capture, usage and storage in our series:

5 projects proving carbon capture is a reality

Petra Nova Power Station

The concept of capturing carbon dioxide (CO2) from power station, refinery and factory exhausts has long been hailed as crucial in mitigating the climate crisis and getting the UK and the rest of the world to net zero. After a number of false starts and policy hurdles, the technology is now growing with more momentum than ever. Carbon capture, use and storage (CCUS) is finally coming of age.

Increasing innovation and investment in the space is enabling the development of CCUS schemes at scale. Today, there are over 19 large-scale CCUS facilities in operation worldwide, while a further 32 in development as confidence in government policies and investment frameworks improves.

Once CO2 is captured it can be stored underground in empty oil and gas reservoirs and naturally occurring saline aquifers, in a process known as sequestration. It has also long been used in enhanced oil recovery (EOR), a process where captured CO2 is injected into oil reservoirs to increase oil production.

Drax Power Station is already trialling Europe’s first bioenergy carbon capture and storage (BECCS) project. This combination of sustainable biomass with carbon capture technology could remove and capture more than 16 million tonnes of CO2 a year and put Drax Power Station at the centre of wider decarbonisation efforts across the region as part of Zero Carbon Humber.

Here are five other projects making carbon capture a reality today:

Snøhvit & Sleipner Vest 

Who: Sleipner – Equinor Energy, Var Energi, LOTOS, KUFPEC; Snøhvit – Equinor Energy, Petoro, Total, Neptune Energy, Wintershall Dean

Where: Norway

Sleipner Vest Norway

Sleipner Vest offshore carbon capture and storage (CCS) plant, Norway [Click to view/download]

Sleipner Vest was the world’s first ever offshore carbon capture and storage (CCS) plant, and has been active since 1996. The facility separates CO2 from natural gas extracted from the Sleipner field, as well as from at the Utgard field, about 20km away. This method of carbon capture means CO2 is removed before the natural gas is combusted, allowing it to be used as an energy source with lower carbon emissions.

Snøhvit, located offshore in Norway’s northern Barents Sea, operates similarly but here natural gas is pumped to an onshore facility for carbon removal. The separated and compressed CO2 from both facilities is then stored, or sequestered, in empty reservoirs under the sea.

The two projects demonstrate the safety and reality of long-term CO2 sequestration – as of 2019, Sleipner has captured and stored over 23 million tonnes of CO2 while Snøhvit stores 700,000 tonnes of CO2 per year.

Petra Nova

Who: NRG, Mitsubishi Heavy Industries America, Inc. (MHIA) and JX Nippon, a joint venture with Hilcorp Energy 

Where: Texas, USA

In 2016, the largest carbon capture facility in the world began operation at the Petra Nova coal-fired power plant.

Using a solvent developed by Mitsubishi and Kansai Electric Power, called KS-1, the CO2 is absorbed and compressed from the exhausts of the plant after the coal has been combusted. The captured CO2 is then transported and used for EOR 80 miles away on the West Ranch oil field.

Carbon capture facility at the Petra Nova coal-fired power plant, Texas, USA

As of January 2020, over 3.5 million tonnes of CO2 had been captured, reducing the plant’s carbon emissions by 90%. Oil production, on the other hand, increased by 1,300% to 4,000 barrels a day. As well as preventing CO2 from being released into the atmosphere, CCUS has also aided the site’s sustainability by eliminating the need for hydraulic drilling.


Gorgon LNG, Barrow Island, Australia [Click to view/download]

Gorgon LNG

Who: Operated by Chevron, in a joint venture with Shell, Exxon Mobil, Osaka Gas, Tokyo Gas, Jera

Where: Barrow Island, Australia

In 2019 CCS operations began at one of Australia’s largest liquified natural gas production facilities, located off the Western coast. Here, CO2 is removed from natural gas before the gas is cooled to -162oC, turning it into a liquid.

The removed CO2 is then injected via wells into the Dupuy Formation, a saline aquifer 2km underneath Barrow Island.

Once fully operational (estimated to be in 2020), the project aims to reduce the facility’s emissions by about 40% and plans to store between 3.4 and 4 million tonnes of CO2 each year.

Quest

Shell’s Quest carbon capture facility, Alberta, Canada

Who: Operated by Shell, owned by Chevron and Canadian Natural Resources

Where: Alberta, Canada

The Scotford Upgrader facility in Canada’s oil sands uses hydrogen to upgrade bitumen (a substance similar to asphalt) to make a synthetic crude oil.

In 2015, the Quest carbon capture facility was added to Scotford Upgrader to capture the CO2 created as a result of making the site’s hydrogen. Once captured, the CO2 is pressurised and turned into a liquid, which is piped and stored 60km away in the Basal Cambrian Sandstone saline aquifer.

Over its four years of crude oil production, four million tonnes of CO2 have been captured. It is estimated that, over its 25-year life span, this CCS technology could capture and store over 27 million tonnes of CO2.

Chevron estimates that if the facility were to be built today, it would cost 20-30% less, a sign of the falling cost of the technology.

Boundary Dam

Who: SaskPower

Where: Saskatchewan, Canada

Boundary Dam, a coal-fired power station, became the world’s first post-combustion CCS facility in 2014.

The technology uses Shell’s Cansolv solvent to remove CO2 from the exhaust of one of the power station’s 115 MW units. Part of the captured CO2 is used for EOR, while any unused CO2 is stored in the Deadwood Formation, a brine and sandstone reservoir, deep underground.

As of December 2019, more than three million tonnes of CO2 had been captured at Boundary Dam. The continuous improvement and optimisations made at the facility are proving CCS technology at scale and informing CCS projects around the world, including a possible retrofit project at SaskPower‘s 305 MW Shand Power Station.

Top image: Carbon capture facility at the Petra Nova coal-fired power plant, Texas, USA

Learn more about carbon capture, usage and storage in our series: