Tag: technology

What is direct air carbon capture and storage (DACS)?

9 July 2021

Carbon capture

What is direct air carbon capture and storage (DACS)?

Direct air carbon capture and storage (DACS, sometimes referred to as DAC or DACCS) is one of the few technologies that can remove carbon dioxide (CO2) from the atmosphere. Unlike other carbon removal technologies that capture CO2 emissions during the process of generating electricity or heat, DACS can be deployed anywhere in the world it can tap into a supply of electricity.

CO2 removal is crucial to meeting the international climate goals set by the 2015 Paris Agreement. But it’s not enough just to cut CO2 emissions, to achieve net zero, it will also be necessary to remove the CO2 that two centuries of industrialisation have released into the environment. As a technology that removes more CO2 from the atmosphere than it releases – assuming it is powered by green electricity – DACS has the potential to play a key role in this process.

Key direct air capture facts

How does DACS work?

DACS could be described as a form of industrial photosynthesis. Just as plants use photosynthesis to convert sunlight and CO2 into sugar, DACS systems use electricity to remove CO2 from the atmosphere using fans and filters.

Air is drawn into the DACS system using an industrial scale fan. Liquid DACS systems pass the air through a chemical solution which removes the CO2 and returns the rest of the air back into the atmosphere.

Solid DACS systems captures CO2 on the surface of a filter covered in a chemical agent, where it then forms a compound. The new compound is heated, releasing the CO2 to be captured and separating it from the chemical agent, which can then be recycled.

The captured CO2 can then be compressed under very high pressure and pumped via pipelines into deep geological formations. This permanent storage process is known as ‘sequestration’.

Alternatively, the CO2 can be pumped under low pressure for immediate use in commercial processes, such as carbonating drinks or cement manufacturing.

A 2021 study by the Coalition for Negative Emissions shows that DACS could provide at least 1Gt of sustainable negative emissions by 2025

DACS fast facts

What role can DACS play in decarbonisation?

CO2 is in the air at the same concentration everywhere in the world. This means that DACS plants can be located anywhere, unlike carbon capture systems that remove CO2 from industrial processes at source.

There are 15 DACS plants currently in operation worldwide – Climeworks operates three in Switzerland, Iceland and Italy. Together, these small-scale plants capture approximately 9,000 tonnes of CO2 per annum. The first large-scale plant, currently being developed in the Permian Basin, Texas, is expected to capture 1,000,000 tonnes (one megatonne) per annum when it becomes operational in 2025.

At just 0.04%, the concentration of CO2 in the atmosphere is very dilute which makes removing and storing it a challenge. This means that DACS costs significantly more than some other CO2 capture technologies – between $200 and $600 (£156-468) per metric tonne. The process also requires large amounts of energy, which adds to the demand for electricity.

However, DACS has the potential to become an important piece in the jigsaw of CO2 removal technologies and techniques that includes nature-based solutions such as planting forests, along with bioenergy with carbon capture and storage (BECCS), soil sequestration and ‘blue carbon’ marine initiatives.

Go deeper

Button: What is bioenergy with carbon capture and storage (BECCS)?

Supporting the deployment of Bioenergy Carbon Capture and Storage (BECCS) in the UK: business model options

8 April 2021

Carbon capture
Innovation engineer inspecting CCUS incubation area BECCS pilot plant at Drax Power Station, 2019

Click to view/download the report PDF.

Drax Power Station is currently exploring the option of adding carbon capture and storage equipment to its biomass-fired generating units. The resulting plant could produce at least 8 million tonnes (Mt) of negative CO2 emissions each year, as well as generating renewable electricity. Drax is planning to make a final investment decision (FID) on its bioenergy with carbon capture and storage (‘BECCS in power’1) investment in Q1 2024, with the first BECCS unit to be operating by 2027.

The potential of BECCS as part of the path to Net Zero has been widely recognised.

  • BECCS in power is an important part of all of the Climate Change Committee (CCC)’s Net Zero scenarios, contributing to negative emissions of between 16- 39Mt CO2e per year by 20502. Investment needs to occur early: by 2035, the CCC sees a role for 3-4GW of BECCS, as part of a mix of low carbon generation3.
  • The Government’s Energy White Paper commits, by 2022, to establishing the role which BECCS can play in reducing carbon emissions across the economy and setting out how the technology could be deployed. The Government has also committed to invest up to £1 billion to support the establishment of carbon capture, usage and storage (CCUS) in four industrial clusters4.
  • National Grid’s 2020 Future Energy Scenarios (FES) indicate that it is not possible to achieve Net Zero without BECCS5.

However, at present, a business model6 which could enable this investment is not in place. A business model is required because a number of barriers and market failures otherwise make economic investment impossible.

  • There is no market for negative emissions. There is currently no source of remuneration for the value delivered by negative emissions, and therefore no return for the investment needed to achieve them.
  • Positive spillovers are not remunerated. Positive spillovers that would be delivered by a first-of-a-kind BECCS power plant, but which are not remunerated include:
    • providing an anchor load for carbon dioxide (CO2) transport and storage (T&S) infrastructure that can be used by subsequent CCS projects;
    • delivering learning that will help lower the costs of subsequent BECCS power plants; and
    • delivering learning and shared skills that can be used across a range of CCS projects, including hydrogen production with CCS.
  • BECCS relies on the presence of CO2 transport and storage infrastructure. Where this infrastructure doesn’t already exist, or where the availability or costs are highly uncertain, this presents a significant risk to investors in BECCS in power.
CCUS incubation area, Drax Power Station, July 2019

CCUS incubation area, Drax Power Station; click image to view/download

Frontier Economics has been commissioned by Drax to develop and evaluate business model options for BECCS in power that could overcome these barriers, and help deliver timely investment in BECCS.

Business model options

We started with a long list of business model options. After eliminating options that are unsuitable for BECCS in power, we considered the following three options in detail.

  • Power Contract for Difference (CfD): the strike price of the CfD would be set to include remuneration for negative emissions, low carbon power and for learnings and spillover benefits.
  • Carbon payment: a contractual carbon payment would provide a fixed payment per tonne of negative emissions. The payment level would be set to include remuneration for negative emissions, low carbon power and for learnings and spillovers.
  • Carbon payment + power CfD: this option combines the two options above. The carbon payment would provide remuneration for negative emissions and learnings and spillovers while the power CfD would support power market revenues for the plant’s renewable power output.

We first considered if committing to any of these business model options for BECCS in power now might restrict future policy options for a broader GGR support scheme. We assessed whether these options could, over time, be transitioned into a broader GGR support scheme (i.e. one not just focused on BECCS in power), and concluded that this would be possible for all of them.

We then considered how these business model options could be funded, and whether the choice of a business model option is linked to a particular source of funds (for example, power CfDs are currently funded by a levy paid by electricity suppliers to the Low Carbon Contracts Company [LCCC]). We concluded that business models do not need to be attached to specific funding sources; all of the options can be designed to fit with numerous different funding options, so the two decisions can be made independently. This means that the business model options can be considered on their own terms, with thinking about funding sources being progressed in parallel.

We then evaluated the three business model options against a set of criteria developed from principles set out in the BEIS consultation on business models for CCS, summarised in the figure below.

Figure 1: Principles for design of business models

Instil investor confidence▪ Attract innovation
▪ Attract new entrants
▪ Instil supply chain confidence
Cost efficiency▪ Drive efficient management of investment costs
▪ Drive efficient quantity of investment
▪ Drive efficient dispatch and operation
▪ Risks allocated in an efficient way, taking into account the impact on the cost of capital
Feasibility▪ Limit administrative burden
▪ Practicality for investors
▪ Requirement for complementary policy
▪ Wider policy and state aid compatibility
▪ Timely implementation
Fair cost sharing▪ Allows fair and practical cost distribution
Ease of policy transition▪ Ease of transition to subsidy free system
▪ Ease of transition to technology neutral solution

Source: Frontier Economics. Click to view/download graphic. 

All three business model options performed well across most criteria. However, our evaluation highlighted some key trade-offs to consider when choosing a business model:

  • investor confidence: the power CfD and the two-part model with a CfD performed better than the carbon payment on this measure, as they shield investors from wholesale power market fluctuations;
  • feasibility: the power CfD performed best on this measure. Because it is already established in existing legislation and is well understood, it will be quick to implement. Introducing a mechanism to provide carbon payments may require new legislation. However, this will be needed in any case to support other CCUS technologies7, and could be introduced in time before projects come online; and
  • potential to become technology neutral and subsidy free: all three options could transition to a mid-term regime which could be technology neutral. However, the stand-alone power CfD performed least well as it does not deliver any learnings around remunerating negative emissions.

Overall, the two-part model performed well across the criteria and would offer a clear path to a technology neutral and subsidy free world, delivering learnings that will be relevant for other GGRs as well.

Conclusions

The UK’s Net Zero target will be challenging to achieve, and will require investment in negative emissions technologies to offset residual emissions from hard-to-abate sectors, as highlighted by the CCC8. BECCS in power is a particularly important part of this picture, and represents a cost-effective means of delivering the scale of negative emissions needed. Early investment in BECCS is also important in insuring against the risk and cost of ”back ending” significant abatement effort.

However, market failures, most notably the lack of a market for negative emissions, lack of remuneration for positive spillovers and learnings, and reliance on availability of T&S infrastructure, mean that without policy intervention, the required level of BECCS in power is unlikely to be delivered in time to contribute to Net Zero.

There are a number of business options available in the near term to overcome these barriers. In our view, a two-part model combining a power CfD and a carbon payment is preferable.

This measure:

  • addresses identified market failures;
  • can be implemented relatively easily and in time to capture benefits of early BECCS in power investment; and
  • can be structured to ensure an efficient outcome for customers (including with reference to investors’ likely cost of capital) and in a way that allocates risks appropriately.

View/download the full report (PDF).

1: Biomass can be combusted to generate energy (typically in the form of power, but this could also be in the form of heat or liquid fuel), or gasified to produce hydrogen. The resulting emissions can then be captured and stored using CCS technology. The focus of this report is on biomass combustion to generate power, with CCS, which we refer to as ‘BECCS in power’. We refer to biomass gasification with CCS as ‘BECCS for hydrogen’.

2: CCC (2020) , The Sixth Carbon Budget, Greenhouse Gas Removals, https://www.theccc.org.uk/wp-content/uploads/2020/12/Sector-summary-GHG-removals.pdf The CCC’s 2019 Net Zero report also saw a role for BECCS, with 51Mt of emissions removals included in the Further Ambition scenario by 2050. CCC (2019), Net Zero: The UK’s Contribution to Stopping Global Warming. https://www.theccc.org.uk/publication/net-zero-the-uks-contribution-to-stopping-global-warming/

3: CCC (2020), Policies for the Sixth Carbon Budget, https://www.theccc.org.uk/wp-content/uploads/2020/12/Policies-for-the-Sixth-Carbon-Budget-and-Net-Zero.pdf

4: BEIS (2020), Powering our Net Zero Future, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/945899/201216_BEIS_EWP_Command_Paper_Accessible.pdf

5: National Grid (2020), Future Energy Scenarios 2020, https://www.nationalgrideso.com/future-energy/future-energy-scenarios/fes-2020-documents

6: In this report, we use “business model” to describe Government market-based incentives for investment and operation. This is in line with the use of this term by BEIS, for example in BEIS (2019), Business Models For Carbon Capture, Usage And Storage, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/819648/ccus-business-models-consultation.pdf

7: BEIS (2020), CCUS: An update on business models for Carbon Capture, Usage and Storage https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/946561/ccus-business-models-commercial-update.pdf

8: CCC (2020) , The Sixth Carbon Budget, Greenhouse Gas Removals, https://www.theccc.org.uk/wp-content/uploads/2020/12/Sector-summary-GHG-removals.pdf

The myths, legends and reality of Cruachan Power Station’s mural

14 October 2020

Sustainable business

Down the kilometre-long tunnel that burrows into the dark rock of Ben Cruachan, above the giant rumbling turbines, sits something unusual for a power station: a work of art.

The wood and gold-leaf mural might seem at odds with the yellow metal turbines, granite cavern walls, and noise and heat around it, but it’s closely connected to the power station and its ties to the surrounding landscape.

The entrance tunnel might take engineers and machines to the heart of Ben Cruachan, but the mural transports viewers to the mountain’s mythical past. It tells the story of how this remarkable engineering achievement came to help power the country.

The narrative of the mural

Much like the machines and physical environment surrounding it, the Cruachan mural is big, measuring 14.6 metres long by 3.6 metres tall. Combining wood, plastic and gold leaf, the relief is interspersed with Celtic crosses, textures evocative of granite rock and gold orbs that resemble the urban lights Cruachan helps to power. Running from left to right, it tells a linear narrative that spans the history of the mountain.

An artist’s impression of the mural in the Visitor Centre at Cruachan

In the first of the mural’s three segments is a Scottish red deer, a native species that still thrives in Scotland today. Below it is the figure of the Cailleach Bheur, a legendary old woman or hag found across Gaelic mythology in Scotland, Ireland and on the Isle of Man. The Cailleach has a symbolic representation of a variety of roles in different folklores, but she commonly appears as a personification of winter, and with that, as a source of destruction.

In the context of Ben Cruachan, Cailleach Bheur is often taken to mean the ‘Old Hag of The Ridges,’ a figure who acts as the mythical guardian of a spring on the mountain’s peak. The mural tells her story, of how she was tasked to cover the well with a slab of stone at sundown and lift it away at sunrise. One evening, however, she fell asleep and failed to cover the well, allowing it to overflow and cause water to cascade down the mountain, flooding the valley below and drowning the people and their cattle.

The mural within the Turbine Hall at Cruachan Power Station undergoing maintenance  [November 2018]

This serves as the legendary origins of Loch Awe, from which Cruachan power station pumps water to the upper reservoir when there’s excess electricity on the grid.

The story claims the water washed a path through to the sea, creating the Pass of Brander. The site of a 1308 battle in the Scottish Wars of Independence, where Robert the Bruce defeated the English-aligned MacDougall and Macnaghten clans.

The mythical first section of the mural is separated by a Celtic-style cross from the modern second segment, which portrays the power station’s construction within Ben Cruachan. Here, four figures represent the four lead engineers of the project from the firms James Williamson & Partners, William Tawse Ltd, Edmund Nuttall Ltd and Merz & McLellan. They stand by the mountain, a roughly cut path running through its core.

At the base of the mural are the faces of 15 men lying on their sides. These are the  15 who were killed in  1962 when the ceiling of the turbine hall caved in during construction. Their uniform expressionless faces, however, turn them into symbols of the 30-plus workers who died while digging and blasting the power station’s tunnels and constructing the dam at the upper reservoir.

Next to this is a fairy tale portrayal of Queen Elizabeth II, who wears a gold grown and holds a sceptre from which electricity flows in a glowing lightning bolt through rock, commanding the power station into life.

The final third of the mural shows the whole power station system within the mountain. The upper reservoir sits nestled in the slopes of Ben Cruachan with water flowing down the mountain to the four turbines and Loch Awe below. Viewed as a whole, the mural takes the audience from mythology to the modern power station, which continues to play a vital role in the electricity system today.

Carving the Cruachan mural

The mural was created by artist Elizabeth Falconer, who was commissioned to create it to celebrate the power station’s opening by the Queen on 15 October 1965. At the time, only two of Cruachan’s four 100 megawatt (MW) reversible turbines were completed and operational, but it was still the first station of its kind to operate at such a scale. Two of the power station’s  turbines were modified with increased capacities meaning Cruachan can both use and generate up to 440 MW.

HRH Queen Elizabeth II opening Cruachan in 1965

HRH Queen Elizabeth II opening Cruachan on 15 October 1965

The project came to Falconer through her husband, a native of Aberdeen who worked as an architect partner to one of Cruachan’s engineering firms. The brief simply requested she create a piece to fill the empty space on the wall of the turbine hall. Deciding to dive into the history and mythology of the mountain, she initially carved the mural in London and only ventured into Hollow Mountain years after it was first put in place, to make renovations on the work.

Cruachan Power Station was a visionary idea and represented a considerable technical and engineering achievement when it opened. The designs and construction of the reversable turbines put this site at the cutting end of modern energy technology.

So, it’s fitting the mural appears distinctly modern in its design, yet tells a story that connects this modern power station to the ancient rock it lives within.

It’s Cruachan’s mural’s location inside the mountain that makes it so unique as a work of art. However, at a time when the electricity grid is changing to an increasingly renewable system, based more around weather and geography, the connections the mural makes between Scotland’s landscape and the modern power station, make it relevant beyond the turbine cavern.

Find out more about Cruachan Power Station

Could hydrogen power stations offer flexible electricity for a net zero future?

26 August 2020

Power generation
Pipework in a chemical factory

We’re familiar with using natural gas every day in heating homes, powering boilers and igniting stove tops. But this same natural gas – predominantly methane – is also one of the most important sources of electricity to the UK. In 2019 gas generation accounted for 39% of Great Britain’s electricity mix. But that could soon be changing.

Hydrogen, the super simple, super light element, can be a zero-carbon emissions source of fuel. While we’re used to seeing it in everyday in water (H2O), as a gas it has been tested as an alternative to methane in homes and as a fuel for vehicles.

Could it also replace natural gas in power stations and help keep the lights on?

The need for a new gas

Car arriving at hydrogen gas station

Hydrogen fuel station

Natural gas has been the largest single source of electricity in Great Britain since around 2000 (aside from the period 2012-14 when coal made a resurgence due to high gas prices). The dominance of gas over coal is in part thanks to the abundant supply of it in the North Sea. Along with carbon pricing, domestic supply makes gas much cheaper than coal, and much cleaner, emitting as much as 60% less CO2 than the solid fossil fuel.

Added to this is the ability of gas power stations to start up, change their output and shut down very quickly to meet sudden shifts in electricity demand. This flexibility is helpful to support the growth of weather-dependant renewable sources of power such as wind or solar. The stability gas brings has helped the country decarbonise its power supply rapidly.

Hydrogen, on the other hand, can be an even cleaner fuel as it only releases water vapour and nitrous oxide when combusted in large gas turbines. This means it could offer a low- or zero-carbon, flexible alternative to natural gas that makes use of Great Britain’s existing gas infrastructure. But it’s not as simple as just switching fuels.

Switching gases

Some thermal power stations work by combusting a fuel, such as biomass or coal, in a boiler to generate intense heat that turns water into high-pressure steam which then spins a turbine. Gas turbines, however, are different.

Engineer works on a turbine at Drax Power Station

Instead of heating water into steam, a simple gas turbine blasts a mix of gas, plus air from the surrounding atmosphere, at high pressure into a combustion chamber, where a chemical reaction takes place – oxygen from the air continuously feeding a gas-powered flame. The high-pressure and hot gasses then spin a turbine. The reaction that takes place inside the combustion chamber is dependent on the chemical mix that enters it.

“Natural gas turbines have been tailored and optimised for their working conditions,” explains Richard Armstrong, Drax Lead Engineer.

“Hydrogen is a gas that burns in the same way as natural gas, but it burns at different temperatures, at different speeds and it requires different ratios of oxygen to get the most efficient combustion.”

Switching a power station from natural gas to hydrogen would take significant testing and refining to optimise every aspect of the process and ensure everything is safe. This would no doubt continue over years, subtly developing the engines over time to improve efficiency in a similar way to how natural gas combustion has evolved. But it’s certainly possible.

What may be trickier though is providing the supply of hydrogen necessary to power and balance the country’s electricity system. 

Making hydrogen

Hydrogen is the most abundant element in the universe. But it’s very rare to find it on its own. Because it’s so atomically simple, it’s highly reactive and almost always found naturally bonded to other elements.

Water is the prime example: it’s made up of two hydrogen atoms and one oxygen atom, making it H2O. Hydrogen’s tendency to bond with everything means a pure stream of it, as would be needed in a power station, has to be produced rather than extracted from underground like natural gas.

Hydrogen as a gas at standard temperature and pressure is known by the symbol H2.

A power station would also need a lot more hydrogen than natural gas. By volume it would take three times as much hydrogen to produce the same amount of energy as would be needed with natural gas. However, because it is so light the hydrogen would still have a lower mass.

“A very large supply of hydrogen would be needed, which doesn’t exist in the UK at the moment,” says Rachel Grima, Research & Innovation Engineer at Drax. “So, at the same time as converting a power plant to hydrogen, you’d need to build a facility to produce it alongside it.”

One of the most established ways to produce hydrogen is through a process known as steam methane reforming. This applies high temperatures and pressure to natural gas to break down the methane (which makes up the majority of natural gas) into hydrogen and carbon dioxide (CO2).

The obvious problem with the process is it still emits CO2, meaning carbon capture and storage (CCS) systems are needed if it is to be carbon neutral.

“It’s almost like capturing the CO2 from natural gas before its combusted, rather than post-combustion,” explains Grima. “One of the advantages of this is that the CO2 is at a much higher concentration, which makes it much easier to capture than in flue gas when it is diluted with a lot of nitrogen.”

Using natural gas in the process produces what’s known as ‘grey hydrogen’, adding carbon capture to make the process carbon neutral is known as ‘blue hydrogen’ – but there are ways to make it with renewable energy sources too.

Electrolysis is already an established technology, where an electrical current is used to break water down into hydrogen and oxygen. This ‘green hydrogen’ cuts out the CO2 emissions that come from using natural gas. However, like charging an electric vehicle, the process is only carbon-neutral if the electricity powering it comes from zero carbon sources, such as nuclear, wind and solar.

It’s also possible to produce hydrogen from biomass. By putting biomass under high temperatures and adding a limited amount of oxygen (to prevent the biomass combusting) the biomass can be gasified, meaning it is turned into a mix of hydrogen and CO2. By using a sustainable biomass supply chain where forests absorb the equivalent of the CO2 emitted but where some fossil fuels are used within the supply chain, the process becomes low carbon.

Carbon capture use and storage (CCUS) Incubation Area, Drax Power Station

Carbon capture use and storage (CCUS) Incubation Area, Drax Power Station

CCS can then be added to make it carbon negative overall, meaning more CO2 is captured and stored at forest level and in below-ground carbon storage than is emitted throughout its lifecycle. This form of ‘green hydrogen’ is known as bioenergy with carbon capture and storage (BECCS) hydrogen or negative emissions hydrogen.

There are plenty of options for making hydrogen, but doing it at the scale needed for power generation and ensuring it’s an affordable fuel is the real challenge. Then there is the issue of transporting and working with hydrogen.

“The difficulty is less in converting the UK’s gas power stations and turbines themselves. That’s a hurdle but most turbine manufacturers already in the process of developing solutions for this,” says Armstrong.

“The challenge is establishing a stable and consistent supply of hydrogen and the transmission network to get it to site.”

Working with the lightest known element

Today hydrogen is mainly transported by truck as either a gas or cooled down to minus-253 degrees Celsius, at which point it becomes a liquid (LH2). However, there is plenty of infrastructure already in place around the UK that could make transporting hydrogen significantly more efficient.

“The UK has a very advanced and comprehensive gas grid. A conversion to hydrogen would be more economic if you could repurpose the existing gas infrastructure,” says Hannah Steedman, Innovation Engineer at Drax.

“The most feasible way to feed a power station is through pipelines and a lot of work is underway to determine if the current natural gas network could be used for hydrogen.”

Gas stove

Hydrogen is different to natural gas in that it is a very small and highly reactive molecule,  therefore it needs to be treated differently. For example, parts of the existing gas network are made of steel, a metal which hydrogen reacts with, causing what’s known as hydrogen embrittlement, which can lead to cracks and failures that could potentially allow gas to escape. There are also factors around safety and efficiency to consider.

Like natural gas, hydrogen is also odourless, meaning it would need to have an odourant added to it. Experimentation is underway to find out if mercaptan, the odourant added to natural gas to give it a sulphuric smell, is also compatible with hydrogen.

But for all the challenges that might come with switching to hydrogen, there are huge advantages.

The UK’s gas network – both power generation and domestic – must move away from fossil fuels if it is to stop emitting CO2 into the atmosphere, and for the country to reach net zero by 2050. While the process will not be as simple as switching gases, it creates an opportunity to upgrade the UK’s gas infrastructure – for power, in homes and even as a vehicle fuel.

It won’t happen overnight, but hydrogen is a proven energy fuel source. While it may take time to ramp up production to a scale which can meet demand, at a reasonable cost, transitioning to hydrogen is a chance to future-proof the gas systems that contributes so heavily to the UK’s stable power system.

What are negative emissions?

21 August 2020

Carbon capture
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

Go deeper

What is carbon capture usage and storage?

Carbon capture
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 the national grid?

Power generation
Electricity grid

What is the grid?

The national grid, or simply the grid, is the network of powerlines, pylons, gas lines and interconnectors that makes up Great Britain’s electricity and gas systems — and the engineers, technology and rules responsible for their seamless operation. It ensures electricity generated anywhere, by any source, can be transmitted to meet the demand for power wherever it’s needed across the country. It heats homes and businesses. It helps us to cook our food.

The national electricity grid consists of a high voltage transmission system, which connects electricity from power stations to substations and smaller local networks – called Distribution Network Operators, or DNOs – which transport electricity into homes and businesses.

Key national grid facts

How does it work?

Transporting electricity around the grid is more complicated than just connecting cables to power generators. In order to move power around the country, things like voltage and frequency of electricity must be balanced and kept uniform at all times. Without this, unstable electricity could damage equipment and ultimately lead to blackouts.

The National Grid Electricity System operator (ESO) is a separate entity from the National Grid company, and is responsible for maintaining the correct voltage, frequency and reserve power levels to ensure electricity is transmitted safely and efficiently at all times.

It does this by working with power generators and energy storage facilities to provide what are known as ‘ancillary services’ – a set of processes that keep the power system in operation, stable and balanced.

The national grid is the network of power stations, powerlines and electricity infrastructure that allows electricity to be generated, transported and used across the country.

Who controls it?

In Great Britain the National Grid company owns and operates the transmission systems which ensure electricity is delivered safely and reliably across the country.

The local distribution system is made up of 14 regional DNO companies, which deliver electricity at a lower voltage from substations to homes and businesses.

Great Britain’s grid incudes England, Scotland, Wales and several surrounding islands. Northern Ireland is part of an island-wide electricity system with the Republic of Ireland.

National grid fast facts

  • Great Britain’s grid is made up of more than 7,000 kilometres of cables, 90,000 pylons, 346 substations, and 1,500 kilometres of underground cables
  • Construction of the grid began on 14 July 1928 and was completed on 5 September 1933
  • It was originally designed to operate as 7 separate, connected grids, before a group of rebellion engineers attempted to run it as one on 29 October 1938. It has run as one grid ever since
  • A decade ago, Britain had 80 individual points of generation to manage. Today there are nearly one million
  • All electricity in Great Britain operates at a frequency of 50Hz. A deviation of just 1% above or below could cause damage

How is the grid changing?

As the sources that generate Great Britain’s electricity change to include more renewables, the grid has also changed.

The grid was built to work with large power stations that operate huge spinning turbines. With decarbonisation it’s evolved to include a greater variety of intermittent weather dependent sources such as wind, solar and decentralised power sources that serve individual buildings or communities.

This makes managing the grid’s stability more complicated, and requires the use of more ancillary services, usually delivered by flexible generators such as thermal power stations.

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What is decarbonisation?

Carbon capture
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?

 

The ideas and tricks inside Great Britain’s plugs

15 July 2020

Electrification
Rewiring a UK 13 amp domestic electric plug

It may be bulkier than its foreign cousins and its flat back might make it the perfect household booby trap, but the UK plug is a modern-day design marvel.

The UK’s ‘G Type’ (or BS 1363) plug is a product of the post-war age. But it has endured for the better part of a century, ensuring homes, business and sockets around the UK have access to safe, usable electricity. Even as the devices they power have changed, become smarter and more connected, the three-prong G Type remains unchanged.

But to understand how it came into being, it’s worth first understanding what makes it such a unique and clever bit of design – including its role in achieving the ambitions of one of Great Britain’s pioneering female engineers, and its money-saving abilities.

What makes Great Britain’s plugs special

The modern plug used across Great Britain (as well as Ireland, Cyprus, Hong Kong and Malaysia) is a smarter and more advanced item than many of its contemporaries. This is thanks to a number of key, but often overlooked, features.

The UK plug is a

A collection of international power point illustrations

The first is its earth prong. Connecting the plug to the earth means if a wire comes loose in, say, a toaster and touches a metal part, the device will short circuit as the electricity runs through to make contact with the earth, rather than the entire item becoming electrified and dangerous.

The longer earth prong also plays the role of ‘gatekeeper’ for the entire plug. When a plug enters a socket the longer earth prong enters before any others, pushing back plastic shutters that sit over the live and neutral entrances. This means when there is no plug in a socket the live and neutral ports, which actually carry electric current to devices, are covered over making it very difficult for a child to push anything dangerous into the socket.

Infographic: What makes the UK plug special?

What makes the UK plug special? [click to download]

Another clever feature inside the Great British plug comes in the form of a fuse connected to the live wire. If there’s an unexpected electrical surge the fuse will blow and cut off the connected device, preventing fires and electrocutions.

All packaged together, the G Type plug is far from the most compact version – yet it is hugely effective. However, these ideas didn’t come together at the flick of a switch.

Pre-war plugs

Going back to end of the 19th Century, the idea of owning devices you could move around your house and connect to the electricity circuit from different rooms was novel.

Electricity’s main role in homes was for lighting and was fixed into walls and ceilings, with their cables hidden. It wasn’t until the rise of new electrical appliances in the 20th century that the need for an easy way to plug electrical items into circuits arose.

A series of two-pronged plugs first emerged in 1883, but there was no standardisation of design which would allow any appliance to be plugged into any socket. That began to change in 1904, when US inventor Harvey Hubbell developed a plug that allowed non-bulb electrical devices to be connected into an existing light socket, eliminating the need for the installation of new sockets.

By 1911, a design for a three-pronged plug with an earth connection had emerged, with manufacturer AP Lundberg bringing the first of this kind of plug to Britain.

By 1934, regulations appeared requiring plugs and sockets to include an earthing prong, which eventually gave birth to a three, cylindrical-pronged plug: the BS 546.

BS 546 plugs

The BS 546 was different from the modern G-Type as they didn’t contain a fuse and were available in five different sizes depending on the needs of the appliance, from small 2 ampere plugs for low-power appliances to a larger 30 ampere version for industrial machinery. The different sizes and spacing of the prongs prevented low-power devices accidentally being plugged into high-power outlets.

Any chance of globally standardising plugs was doomed from the beginning, as different companies in different countries all began developing their own plugs for their products as electricity rapidly gained uptake.

Some attempts were made by the International Electrotechnical Commission (IEC) to standardise plugs globally but the Second World War put a stop to any progress.   

Electricity for the people

Great Britain emerged from the Second World War with its national grid standing strong. The challenge now was to make electricity not just the power source of factories and wealthy people’s homes, but something available for everyone in the wave of new post-war construction.

Other countries, not seeing as much damage to their housing stock as the UK, did not have the same opportunity to rethink domestic electricity to such an extent. Therefore, the Institution of Electrical Engineers (IEE) assembled a 20-person committee to consider the electrical requirements of the country’s new homes.

Caroline Haslett

Breaking new ground: Caroline Haslett

The sole woman on the committee, Caroline Haslett, had been breaking new ground for female engineers since before World War One. In her career she worked with turbine inventor Charles Parsons and his wife (an engineer in her own right) and in 1932 became the first woman selected to join the IEE. Her passion for electricity went so far as for her will to request she be cremated via electricity.

She had long believed in the potential for domestic electricity to improve women’s lives by freeing them from the drudgery of pre-electric domestic chores, from handwashing clothes to cooking on coal-fuelled stoves. This included ensuring electricity was safe for the people using electricity around the home which in the 1940s was primarily women, who also did the vast majority of childcare.

Haslett’s drive to make electricity safe in the home was pivotal in shaping many of the IEE’s safety requirements for post-war domestic electricity, including what have become the country’s standard plugs and sockets.

There was another factor aside from safety at play. The material cost of the war meant copper, the main material used in electrical wiring, was in short supply, so the IEE came up with a new way of wiring homes that would in turn shape our plugs.

Shifting fuses to save copper

Before the war, British sockets were all separately wired back to a central fuse box. It made sense, because if something went wrong only the fuse connected to that socket would blow rather than the whole house.

However, to cut the amount of copper used the IEE instead proposed a clever workaround where the home’s electrical sockets are looped up in one Ring Circuit, with the fuses moved to the plugs themselves. So, if something went wrong in an appliance the fault would stop at the plug, where the fuse could easily be accessed and replaced. Lighting fixtures remained wired in a separate circuit from sockets as they require less current to operate.

Copper Wiring

Copper was short in supply during World War Two.

This hidden fuse, is a big differentiator from other plug types and adds to the G Type’s safety credentials. However, the IEE had to ensure people did not mistakenly insert older three-prong BS 546 plug styles without fuses into the sockets.

The answer was as simple as switching the socket holes from round to rectangle. It means the older round cylinder prongs wouldn’t fit into the slot designed for the rectangles found on plugs today.

The G Type plug might seem cumbersome compared to the European or US models, but in the 70-plus years since its introduction its three prongs and in-built fuse, has proved an enduring design that can power new devices and smart technology, while remaining one of the safest plugs in the world.