Tag: Negative emissions

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

22 April 2020

Carbon capture
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

11 March 2020

Carbon capture
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

4 March 2020

Carbon capture
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: