Tag: technology

4 of the longest running electrical objects

15 June 2020

Electrification

How long do your electrical devices last? We’re not talking about battery life, but the overall lifetime of the items we use every day that are powered by electricity.

It’s accepted that today’s electrical devices have short life spans, in part a symptom of rapidly evolving technology fuelling the need for constant consumer updates and in part a result of planned obsolescence (devices being manufactured to fail within a set number of years to encourage repeat purchases). Electrical devices aren’t purchased with the belief they will last a lifetime.

But it hasn’t always been this way. Before rapid technological development and the rise of fast consumerism, devices were built to last.

Over the relatively short history of electrical appliances, there are tools and equipment that have operated for decades. Some of these remain in operation today with hardly any alterations, but for a few tweaks here and there to upgrade or preserve.

Built to last, here are a few of the longest running electrical inventions.

The Oxford Electric Bell located in the Clarendon Laboratory, University of Oxford.

1840 – The Oxford Electric Bell

The Oxford Electric Bell is not your typical bell – not just in how it looks, but in the fact it has been in constant operation since the mid 19th Century. It consists of two primitive batteries called ‘dry piles’ with bells fitted at each end and a metal ball that vibrates between them to very quietly, continuously ring.

Its original purpose is unidentified, but what is known is that the bell is the result of an experiment put on by the London instrument-manufacturing firm Watkins and Hill in 1840. Acquired by Robert Walker, a physics professor at the University of Oxford in the mid 1800s, it’s displayed at Oxford’s Clarendon Laboratory which explains why it’s also known as the Clarendon Pile.

The exact make-up of the dry piles is unknown, as no one wants to tamper with them to investigate their composition out for fear of ending the bell’s 179-year-long streak. As a result, confusion remains as to why The Oxford Electric Bell has remained in operation for so long.

Souter Lighthouse, Tyneside, England.

1871 – Souter Lighthouse in South Shields, UK

The lamp in the Souter lighthouse, situated between the rivers Tyne and Wear, was the most advanced of its day when it was first constructed. Designed to use an alternating electric current, it was the first purpose-built, electrically powered lighthouse in the world. Although no longer in operation today, it ran unchanged for nearly 50 years.

The light was generated using carbon arc lamps, and it originally produced a beam of red light that would come on once every five seconds.

Souter’s original lamp operated unchanged from 1871 to 1914, when it was replaced by more conventional oil lamps. It was altered again to run on mains electric power in 1952 and was finally deactivated in 1988.

1896 – The Isle of Man’s Manx Electric Railway

Tourism hit the Isle of Man in the 1880s and with it came the construction of hotels and boarding houses. Two businessmen saw this as an opportunity to purchase a large estate on the island and develop it into housing and a pleasure development. The Manx Parliament approved the sale in 1892 on one condition: that a road and a tramway be built to give people access.

Snaefell mountain railway station, Isle of Man.

It was decided that the tram would be electric, and work began in the spring of 1893, with the tram system up and running by September of that year. Although the track and its cars have been extended and updated over time, the first three cars remain the longest running electric tramcars in the world.

Photograph by Dick Jones (centennialbulb.org)

1902 – The Centennial Bulb

The unassuming Centennial Bulb has been working in the Livermore, California Fire Department for 117 years. The bulb was first installed in 1902 in the department’s hose cart house, but was later moved to Livermore’s Fire Station 6, where it has been illuminated for more than a million hours.

Throughout its life the Centennial Bulb has seen just two interruptions: for a week in 1937 when the Firehouse was refurbished, and in May 2013 when it was off for nine and a half hours due to a failed power supply. Made by the Shelby Electric Company, the hand-blown bulb previously shone at 60 watts but has since been dimmed to 4 watts.

While this means it isn’t able to actually illuminate much, it is a reminder that despite the disposable nature of many modern electrical devices, it’s possible to build electrical items that last.

5 exciting energy innovations that you should know about in 2020

5 June 2020

Power generation

As we head into the 2020s, it’s an exciting time for energy. A deeper level of climate consciousness has led to crucial changes in populations’ attitudes and thinking around how we power our lives – adapting to a new set of energy standards has become essential.

It’s also driving innovation in energy technology, leading to the rise of a number of emerging technologies designed to support the global energy transition in new ways. From domestic solar and wind generation, to leaps forward in recycling and aeroplane fuel, here are five new energy ideas in the 2020s pipeline.

Miniature turbines for your garden

Think of a wind farm and you might think of giant structures located in remote, windswept areas, but that’s quickly changing.

IceWind is developing residential wind turbines that use the same generator-principal as large-scale wind farms, just on a much smaller scale. A set of three outer and three inner vertical blades rotate when the wind passes through them, providing spinning mechanical energy that passes through the generator and is converted to electricity.

Constructed from durable stainless steel, carbon fibre and aluminium, the CW1000 model can handle wind speeds of up to 134 miles per hour. To ensure they’re fit for domestic use, the units are adapted to have a maximum height of just over 3 metres and make less than 40 decibels of noise – roughly equivalent to quiet conversation.

The Icelandic company says it aims to decentralise and democratise energy generation by making wind power accessible to people anywhere in the world.

Expanding solar to cover more surfaces

As solar technology becomes more widespread and easier to implement, more communities are turning to a prosumer approach and generating their own power.

Roof panels to date have been the most common way to domestically capture and convert rays, but Solecco is taking it a step further, offering solar roof tiles. These work in the same way as roof panels, using photovoltaic cells made of silicon to convert sunlight into electricity. But by covering more surface area, entire roofs can be used to generate solar energy, rather than single panels.

Environmental Street Furniture takes it a step further by bringing small scale solar generation into many aspects of the urban environment such as smart benches, rubbish bins, and solar lighting in green spaces. This opens up opportunities for powering cities, including incorporating charging stations and network connectivity, which in turn enables social power sharing.

Re-purposing plastic 

Global recycling rates currently sit at approximately 18%, indicating there are still further steps to take in ensuring single-use products are eliminated.

Plastic is a major target in the war on disposal, and for good reason. By 2015, the world had produced over seven billion tonnes of plastic. Greenology is tackling this by harnessing a process called pyrolysis to turn plastic into power. By heating waste at a very high temperature without oxygen, the plastic is breaks down without combusting.

This process produces bio-oils, which can be used to create biofuels. The benefits of this innovative approach to waste are twofold: not only can plastic be repurposed, which minimises the lasting impact single-use plastic has on the planet, but the creation of biofuel offers a power source for everything from transport to generating electricity.

Storing heat for the home

Decarbonising heating is one of the global challenges yet to have a clear answer. Pumped Heat Ltd (PHL) is developing a potential solution with its heat battery technology. The company has found a solution that enables its devices to charge up and store electricity during ‘off-peak’ hours (when electricity is at its cheapest) and then use this energy to generate heating and hot water for homes as it is required. As the grid continues to decarbonise, and as renewable power becomes cheaper and more accessible, the electricity used to charge these units will approach zero carbon content.

The heat battery technology utilises vacuum insulation, losing 10 times less heat than a conventional night storage heater. In contrast, air sourced heat pumps (a more commonly used type of heat pump), operate in real time when a home needs heating. They take water at its delivery temperature (which can be very cold, during the winter months) and heat it using electricity available at that time. Pumped Heat’s storage system instead ensures there is always heat available, maintaining a consistent temperature for hot water or central heating, rather than just when there is an excess of electricity.

The company claims the benefit of using a heat battery system is that it is cheaper than an oil or LPG boiler, in a world where renewable electricity production, both domestic and on a national level, is only set to increase.

Waste-powered planes

As some of the most fossil fuel-reliant industries in the world, travel and transport are actively seeking alternative and more sustainable ways to keep them powered in long run.

Velocys aims to do this using waste. The company is developing sustainable fuels for aviation and heavy goods transport, using the Fischer-Tropsch method of gasifying waste. This involves turning waste materials – such as domestic refuse and woody waste – into clean jet fuel using a catalytic chemical reaction, where synthesis gases (carbon monoxide and hydrogen) are converted into liquid hydrocarbons that can then be used for fuel.

Not only does this make use of waste products that could have ended up in landfill, but it produces much cleaner fuels, that emit less particle matter and harmful pollutants into the atmosphere.

As we enter a new decade of invention, the world is focusing on more sustainable alternatives to power our lives, and these innovative solutions to current environmental issues will continue to inspire creativity.

14 moments that electrified history

13 May 2020

Electrification

Electricity is such a universal and accepted part of our lives it’s become something we take for granted. Rarely do we stop to consider the path it took to become ubiquitous, and yet through the course of its history there have been several eureka moments and breakthrough inventions that have shaped our modern lives. Here are some of the defining moments in the development of electricity and power.

2750 BC – Electricity first recorded in the form of electric fish

Ancient Egyptians referred to electric catfish as the ‘thunderers of the Nile’, and were fascinated by these creatures. It led to a near millennia of wonder and intrigue, including conducting and documenting crude experiments, such as touching the fish with an iron rod to cause electric shocks.

500 BC – The discovery of static electricity

Around 500 BC Thales of Miletus discovered that static electricity could be made by rubbing lightweight objects such as fur or feathers on amber. This static effect remained unknown for almost 2,000 years until around 1600 AD, when William Gilbert discovered static electricity in earnest.

1600 AD – The origins of the word ‘electricity’

The Latin word ‘electricus’, which translates to ‘of amber’ was used by the English physician, William Gilbert to describe the force exerted when items are rubbed together. A few years later, English scientist Thomas Browne translated this into ‘electricity’ in his written investigations in the field.

1751 – Benjamin Franklin’s ‘Experiments and Observations on Electricity’

This book of Benjamin Franklin’s discoveries made about the behaviour of electricity was published in 1751. The publication and translation of American founding father, scientist and inventor’s letters would provide the basis for all further electricity experimentation. It also introduced a host of new terms to the field including positive, negative, charge, battery and electric shock.

1765 – James Watt transforms the Industrial Revolution

Watt studies Newcomen’s engine

James Watt transformed the Industrial Revolution with the invention of a modified Newcome engine, now known as the Watt steam engine. Machines no longer had to rely on the sometimes-temperamental wind, water or manpower – instead steam from boiling water could drive the pistons back and forth. Although Watt’s engine didn’t generate electricity, it created a foundation that would eventually lead to the steam turbine – still the basis of much of the globe’s electricity generation today.

James Watt’s steam engine

Alessandro Volta

1800 – Volta’s first true battery

Documented records of battery-like objects date back to 250 BC, but the first true battery was invented by Italian scientist Alessandro Volta in 1800. Volta realised that a current was created when zinc and silver were immersed in an electrolyte – the principal on which chemical batteries are still based today.

1800s – The first electrical cars

Breakthroughs in electric motors and batteries in the early 1800s led to experimentation with electrically powered vehicles. The British inventor Robert Anderson is often credited with developing the first crude electric carriage at the beginning of the 19th century, but it would not be until 1890 that American chemist William Morrison would invent the first practical electric car (though it closer resembled a motorised wagon), boasting a top speed of 14 miles per hour.

Michael Faraday

1831 – Michael Faraday’s electric dynamo

Faraday’s invention of the electric dynamo power generator set the precedent for electricity generation for centuries to come. His invention converted motive (or mechanical) power – such as steam, gas, water and wind turbines – into electromagnetic power at a low voltage. Although rudimentary, it was a breakthrough in generating consistent, continuous electricity, and opened the door for the likes of Thomas Edison and Joseph Swan, whose subsequent discoveries would make large-scale electricity generation feasible.

1879 – Lighting becomes practical and inexpensive

Thomas Edison patented the first practical and accessible incandescent light bulb, using a carbonised bamboo filament which could burn for more than 1,200 hours. Edison made the first public demonstration of his incandescent lightbulb on 31st December 1879 where he stated that, “electricity would be so cheap that only the rich would burn candles.” Although he was not the only inventor to experiment with incandescent light, his was the most enduring and practical. He would soon go on to develop not only the bulb, but an entire electrical lighting system.

Holborn Viaduct power station via Wikimedia

1882 – The world’s first public power station opens

Holborn Viaduct power station, also known as the Edison Electric Light Station, burnt coal to drive a steam turbine and generate electricity. The power was used for Holborn’s newly electrified streetlighting, an idea which would quickly spread around London.

1880s – Tesla and Edison’s current war

Nikola Tesla and Thomas Edison waged what came to be known as the current war in 1880s America. Tesla was determined to prove that alternating current (AC) – as is generated at power stations – was safe for domestic use, going against the Edison Group’s opinion that a direct current (DC) – as delivered from a battery – was safer and more reliable.

Inside an Edison power station in New York

The conflict led to years of risky demonstrations and experiments, including one where Tesla electrocuted himself in front of an audience to prove he would not be harmed. The war continued as they fought over the future of electric power generation until eventually AC won.

Nikola Tesla

1901 – Great Britain’s first industrial power station opens

Before Charles Mertz and William McLellan of Merz & McLellan built the Neptune Bank Power Station in Tyneside in 1901, individual factories were powered by private generators. By contrast, the Neptune Bank Power Station could supply reliable, cheap power to multiple factories that were connected through high-voltage transmission lines. This was the beginning of Britain’s national grid system.

1990s – The first mass market electrical vehicle (EV)

Concepts for electric cars had been around for a century, however, the General Motors EV1 was the first model to be mass produced by a major car brand – made possible with the breakthrough invention of the rechargeable battery. However, this EV1 model could not be purchased, only directly leased on a monthly contract. Because of this, its expensive build, and relatively small customer following, the model only lasted six years before General Motors crushed the majority of their cars.

2018 – Renewable generation accounts for a third of global power capacity

The International Renewable Energy Agency’s (IRENA) 2018 annual statistics revealed that renewable energy accounted for a third of global power capacity in 2018. Globally, total renewable electricity generation capacity reached 2,351 GW at the end of 2018, with hydropower accounting for almost half of that total, while wind and solar energy accounted for most of the remainder.

The UK needs negative emissions from BECCS to reach net zero – here’s why

7 April 2020

Carbon capture
Early morning sunrise at Drax Power Station

Reaching the UK’s target of net zero greenhouse gas emissions by 2050 means every aspect of the economy, from shops to super computers, must reduce its carbon footprint – all the way down their supply chains – as close to zero as possible.

But as the country transforms, one thing is certain: demand for electricity will remain. In fact, with increased electrification of heating and transport, there will be a greater demand for power from renewable, carbon dioxide (CO2)-free sources. Bioenergy is one way of providing this power without reliance on the weather and can offer essential grid-stability services, as provided by Drax Power Station in North Yorkshire.

Close up of electricity pylon tower

Close up of electricity pylon tower

Beyond just power generation, more and more reports highlight the important role the next evolution of bioenergy has to play in a net zero UK. And that is bioenergy with carbon capture and storage or BECCS.

A carbon negative source of power, abating emissions from other industries

The Committee on Climate Change (CCC) says negative emissions are essential for the UK to offset difficult-to-decarbonise sectors of the economy and meet its net zero target. This may include direct air capture (DAC) and other negative emissions technologies, as well as BECCS.

BECCS power generation uses biomass grown in sustainably managed forests as fuel to generate electricity. As these forests absorb CO2 from the atmosphere while growing, they offset the amount of CO2 released by the fuel when used, making the whole power production process carbon neutral. Adding carbon capture and storage to this process results in removing more CO2 from the atmosphere than is emitted, making it carbon negative.

Pine trees grown for planting in the forests of the US South where more carbon is stored and more wood inventory is grown each year than fibre is extracted for wood products such as biomass pellets

Pine trees grown for planting in the forests of the US South where more carbon is stored and more wood inventory is grown each year than fibre is extracted for wood products such as biomass pellets

This means BECCS can be used to abate, or offset, emissions from other parts of the economy that might remain even as it decarbonises. A report by The Energy Systems Catapult, modelling different approaches for the UK to reach net zero by or before 2050, suggests carbon-intensive industries such as aviation and agriculture will always produce residual emissions.

The need to counteract the remaining emissions of industries such as these make negative emissions an essential part of reaching net zero. While the report suggests that direct air carbon capture and storage (DACCS) will also play an important role in bringing CO2 levels down, it will take time for the technology to be developed and deployed at the scale needed.

Meanwhile, carbon capture use and storage (CCUS) technology is already deployed at scale in Norway, the US, Australia and Canada. These processes for capturing and storing carbon are applicable to biomass power generation, such as at Drax Power Station, which means BECCS is ready to deploy at scale from a technology perspective today.

As well as counteracting remaining emissions, however, BECCS can also help to decarbonise other industries by enabling the growth of a different low carbon fuel: hydrogen.

Enabling a hydrogen economy

The CCC’s ‘Hydrogen in a low-carbon economy report’ highlights the needs for carbon zero alternatives to fossil fuels – in particular, hydrogen or H2.

Hydrogen produced in a test tube

Hydrogen produced in a test tube

When combusted, hydrogen only produces heat and water vapour, while the ability to store it for long periods makes it a cleaner replacement to the natural gas used in heating today. Hydrogen can also be stored as a liquid, which, coupled with its high energy density makes it a carbon zero alternative to petrol and diesel in heavy transport.

There are various ways BECCS can assist the creation of a hydrogen economy. Most promising is the use of biomass to produce hydrogen through a method known as gasification. In this process solid organic material is heated to more than 700°C but prevented from combusting. This causes the material to break down into gases: hydrogen and carbon monoxide (CO). The CO then reacts with water to form CO2 and more H2.

While CO2 is also produced as part of the process, biomass material absorbs CO2 while it grows, making the overall process carbon neutral. However, by deploying carbon capture here, the hydrogen production can also be made carbon negative.

BECCS can more indirectly become an enabler of hydrogen production. The Zero Carbon Humber partnership envisages Drax Power Station as the anchor project for CCUS infrastructure in the region, allowing for the production of ‘blue’ hydrogen. Blue hydrogen is produced using natural gas, a fossil fuel. However, the resulting carbon emissions could be captured. The CO2 would then be transported and stored using the same system of pipelines and a natural aquifer under the North Sea as used by BECCS facilities at Drax.

This way of clustering BECCS power and hydrogen production would also allow other industries such as manufactures, steel mills and refineries, to decarbonise.

Lowering the cost of flexible electricity

One of the challenges in transforming the energy system and wider economy to net zero is accounting for the cost of the transition.

The Energy Systems Catapult’s analysis found that it could be kept as low as 1-2% of GDP, while a report by the National Infrastructure Commission (NIC) projects that deploying BECCS would have little impact on the total cost of the power system if deployed for its negative emissions potential.

The NIC’s modelling found, when taking into consideration the costs and generation capacity of different sources, BECCS would likely be run as a baseload source of power in a net zero future. This would maximise its negative emissions potential.

This means BECCS units would run frequently and for long periods, uninterrupted by changes in the weather, rather than jumping into action to account for peaks in demand. This, coupled with its ability to abate emissions, means BECCS – alongside intermittent renewables such as wind and solar – could provide the UK with zero carbon electricity at a significantly lower cost than that of constructing a new fleet of nuclear power stations.

The report also goes on to say that a fleet of hydrogen-fuelled power stations could also be used to generate flexible back-up electricity, which therefore could be substantially cheaper than relying on a fleet of new baseload nuclear plants.

However, for this to work effectively, decisions need to be made sooner rather than later as to what approach the UK takes to shape the energy system before 2050.

The time to act is now

What is consistent across many different reports is that BECCS will be essential for any version of the future where the UK reaches net zero by 2050. But, it will not happen organically.

Sunset and evening clouds over the River Humber near Sunk Island, East Riding of Yorkshire

Sunset and evening clouds over the River Humber near Sunk Island, East Riding of Yorkshire

A joint Royal Society and Royal Academy of Engineering Greenhouse Gas Removal report, includes research into BECCS, DACCS and other forms of negative emissions in its list of key actions for the UK to reach net zero. It also calls for the UK to capitalise on its access to natural aquifers and former oil and gas wells for CO2 storage in locations such as the North Sea, as well as its engineering expertise, to establish the infrastructure needed for CO2 transport and storage.

However, this will require policies and funding structures that make it economical. A report by Vivid Economics for the Department for Business, Energy and Industrial Strategy (BEIS) highlights that – just as incentives have made wind and solar viable and integral parts of the UK’s energy mix – BECCS and other technologies, need the same clear, long-term strategy to enable companies to make secure investments and innovate.

However, for policies to make the impact needed to ramp BECCS up to the levels necessary to bring the UK to net zero, action is needed now. The report outlines policies that could be implemented immediately, such as contracts for difference, or negative emissions obligations for residual emitters. For BECCS deployment to expand significantly in the 2030s, a suitable policy framework will need to be put in place in the 2020s.

Beyond just decarbonising the UK, a report by the Intergovernmental Panel on Climate Change (IPCC) highlights that BECCS could be of even more importance globally. Differing scales of BECCS deployment are illustrated in its scenarios where global warming is kept to within 1.5oC levels of pre-industrial levels, as per the Paris Climate agreement.

BECCS has the potential to play a vital role in power generation, creating a hydrogen economy and offsetting other emissions. As it continues to progress, it is becoming increasingly effective and cost efficient, offering a key component of a net zero UK.

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:

Why spin a turbine without generating power?

12 February 2020

Power generation
Turbine at Cruachan Power Station

Massive spinning machinery is a big part of electricity generation whether it’s a wind turbine, hydro plant or biomass generator.

But big spinning turbines don’t just pump electricity out onto the grid. They also play a crucial role in keeping the electricity system stable, safe and efficient. This is because big, heavy spinning turbines add something else to the grid: inertia.

This is defined as an object’s resistance to change but in the context of electricity it helps the grid remain at the right frequency and voltage level. In short, they help the grid remain stable.

However, as electricity systems in Great Britain and other parts of the world move away from coal and gas to renewables, such as wind turbines, solar panels and interconnectors, the level of inertia on the system is falling.

“We need the inertia, we don’t need the megawatts,” explains Julian Leslie, Head of Networks at the National Grid Electricity System Operator (ESO). “But in today’s market we have to supply the megawatts and receive the inertia as a consequence.”

Turbine at Drax Power Station

Engineer inspecting turbine blades at Drax Power Station

The National Grid ESO is taking a new approach to this aspect of grid stability by using what are called synchronous condensers. These complicated-sounding pieces of machinery are actually quite straightforward in their concept: they provide inertia to the grid without generating unnecessary power.

These come in the form of:

  • Existing generators that remain connected to the grid but refrain from producing electricity.
  • Purpose built machines whose only function is to act as synchronous condensers, never generating real power. These may be fitted with flywheels to increase their mass and, in consequence, their inertia.

This means that spinning without generating is about to become a very important part of Great Britain’s electricity system.

Around and around

Electricity generators that spin at 3,000 rpm are described as synchronous generators because they are in sync with the grid’s frequency of 50Hz. These include coal, gas, hydro, biomass turbines and nuclear units. Most spin at 3000 rpm, some machines much less (e.g. 750 rpm). Thanks to the way they are designed, they are all synchronised together at the same, higher speed.

Then there are wind turbines where the generated power is not synchronised to the grid system. Termed asynchronous generators, these machines do not have readily accessible stored energy (inertia) and do not contribute to the stability of the system. Interconnectors and solar panels are also asynchronous.

It’s important that Great Britain’s whole grid is kept within 1% of the 50Hz frequency, otherwise the voltage of electricity starts to fluctuate, damaging equipment, becoming less efficient, even dangerous, or resulting in blackouts.

Say a power station or a wind farm were to drop offline, as occurred in August 2019, this would cause the amount of power on the grid to suddenly fall. But it is not just the power that changes – the frequency and voltage also fluctuate dramatically which can cause equipment damage and ultimately, towns, cities or widespread areas to lose power.

Running machines that have inertia act like the suspension on a car – they dampen those fluctuations, so they are not as drastic. The big spinning machines keep spinning, buying valuable milliseconds for the grid to react, often automatically, before the damage becomes widespread.

However, as a consequence of decarbonisation, more solar panels and wind turbines are now on the system and there are fewer spinning turbines, leading to lower levels of inertia on the grid.

“There are periods when renewable generation and flow from interconnectors are so great that it displaces all conventional, rotational power plants,” says Leslie. “Today, bringing more inertia onto the grid may mean switching off renewables or interconnectors, and then replacing them with rotating plants and the megawatts associated with that.”

Creating a market for inertia and synchronous condensers offers a new way forward – providing inertia without unneeded megawatts or emissions from fossil fuels.

A new spin on grid stability

At the start of 2020, The National Grid ESO began contracting parties, including Drax’s Cruachan pumped-hydro power station, to operate synchronous condensers and provide inertia to the grid when needed.

The plans mark a departure from the previous system where inertia and voltage control from electricity generators was taken for granted.

Cruachan Power Station is already capable of running its units in synchronous condenser mode (one of its units, opened up for maintenance, is pictured at the top of this article). This involves an alternator acting as a motor, offering inertia to the grid without generating unneeded electricity. Other service providers will repurpose existing turbines, construct new machines or develop new technologies that can electronically respond to the grid’s need for stability.

Synchronous condensers, or the idea of spinning a turbine freely without generating power, are not new concepts; power stations in the second half of the 20th century could shut down certain generating units but keep them spinning online for voltage control.

In the 1960s and 70s, some substations – where the voltage of electricity is stepped up and down from the transmission system – also deployed stand-alone synchronous condensers. These were also used to provided inertia as well as voltage control but are long since decommissioned.

Synchronous condenser installation at Templestowe substation, Melbourne Victoria, Australia. By Mriya via Wikimedia.

“Synchronous condensers are a proven technology that have been used in the past,” says Leslie. “And there are many new technologies we are now exploring that can deliver a similar service.”

Cheaper, cleaner, more stable

Commercial UK wind turbines

The National Grid ESO estimates the technology will save electricity consumers up to £128 million over the next six years. Savings, which come from negating the need for the grid to call upon fossil fuels for inertia as coal, oil and gas, become increasingly uneconomical across the globe as carbon taxes grow.

The fact that synchronous condensers do not produce electricity also saves money the grid may have had to pay out to renewable generators to stop them producing electricity or to storage systems to absorb excess power.

“It means the market can deliver the renewable flow without the grid having to pay to restrain it or to pay for gas to stabilise the system,” says Leslie. “Not only does this allow more renewable generation, but it also reduces the cost to the consumer.”

In a future energy system, where there is an abundance of renewable electricity generations, synchronous condensers will be crucial in keeping the grid stable. The National Grid ESO’s investment in the technology further highlights the importance of new ideas and innovation to balance the grid through this energy transition.

Synchronous generation provides benefits to system stability beyond the provision of inertia. In a subsequent article we’ll also explore how synchronous condensers can assist with voltage stability and help regional electricity networks and customers to remain connected to the national system during and after faults.

Read about the past, present and future of the country’s electricity system in Could Great Britain go off grid? 

6 disused power stations renovated and reimagined

23 January 2020

Power generation
E-WERK entrance

The Tate Modern and Battersea Power Station along the banks of the Thames are architectural icons of the London skyline. But before they were landmarks, they were oil- and coal-burning power stations, right in the heart of the city they powered.

As the city developed, the technology used to generate power advanced, and the need for cleaner fuel sources grew, the requirement for large, city-based fossil fuel power stations like these fell. The closure of Battersea and the Bankside power stations became inevitable.

Rather than knocking them down, however, it was clear their scale, heritage and location could be repurposed to meet an entirely new set of needs for the city. Now, as an art gallery and modern, mixed-use neighbourhood space, they remain in service to the city while retaining part of their heritage.

Eindhoven’s Innovation Powerhouse, Netherlands

Eindhoven’s Innovation Powerhouse, Netherlands. Photo: Tycho Merijn.

The reimagining of disused power stations is not just a London phenomenon. It is one seen around the world, where industrial buildings like these are being transformed for a range of purposes.

Eindhoven’s Innovation Powerhouse

Eindhoven’s Innovation Powerhouse in the Netherlands remains distinguishable as a power station due to its enormous coal chimneys, but today it serves a different purpose. The original skeleton of the building has been repurposed as a creative office space for innovative tech companies. The open plan structure encourages collaboration and creativity and its location right in the city centre makes it easily accessible to employees. In a nod to its previous use, however, a biogas plant remains situated next door, burning wood waste to produce renewable electricity and heat for the building.

Beloit’s cultural ‘Powerhouse’

Like Innovation Powerhouse, the exterior of Blackhawk Generating Station in Beloit, Wisconsin remains clearly identifiable as a power station. A century ago the once gas-fired plant supplied peak-time electricity to surrounding cities, but since being bought by Beloit University, it’s being transformed into ‘The Powerhouse’– a leisure and cultural centre for both students and the general public. Designs include an auditorium, a health and wellness hub, a swimming pool, lecture halls and more. It sits along the Rock River, between the university and the city – a prime location for bringing communities together, and is due to open in January 2020.

CGI of The Powerhouse, Beloit College Wisconsin. Image: Studio Gang Architects

An artist’s impression of The Powerhouse, Beloit College Wisconsin. Photo: Studio Gang Architects.

The Tejo Power Station Electricity Museum, Lisbon, Portugal.

Lisbon’s electricity museum

The Tejo Power Station once supplied electricity to the whole of Lisbon. Today it’s a museum and art gallery, but remains a testament to Portugal’s technological, historical and industrial heritage. It pays homage to the evolution of electricity through a permanent collection that includes original machinery from its construction in 1908, and charts its evolution from baseload electricity generator to standby power station used only to complement the country’s prominent supply of hydro plants. It’s a space that celebrates the heritage of the building, an attitude reflected throughout Portugal – there is even an energy museums roadmap created for people to tour a trail of decommissioned power stations.

Rome’s renaissance power station

Centrale Montemartini Thermoelectric plant was Rome’s first public power station, operating between 1912-1963. Decommissioned in the 1960s, it was adapted to temporarily house an exhibition of renaissance sculptures and archaeological finds from Rome’s Capitoline Museums that were at the time undergoing renovation. The clash of the classical artworks and the power station’s original equipment was such a success that it has been open ever since.

Centrale Montemartini, Rome, Italy.

Berlin’s E-WERK Luckenwalde

Why replace a power station with an art gallery if it could in fact be both? Berlin’s E-WERK Luckenwalde is a hybrid – what was once a coal power plant before the collapse of communism in 1989, is now both a renewable power plant and an art gallery. It uses waste woodchips from neighbouring companies to generate and sell power to the grid to fund the cost of a contemporary art centre housed inside it. It still generates electricity, only this time it’s renewable and powers the art gallery, which in turn energises the artistic community of Berlin.

 

Copenhagen’s futuristic Amager Bakke Waste-to-Energy-Plant

 Copenhagen’s Amager Bakke Waste-to-Energy-Plant is one of the cleanest incineration plants in the world. Opened in 2017 to replace a nearby 45-year-old incineration plant, it burns municipal waste to create heat and power for the surrounding area. What really sets it apart, however, is its artificial ski slope cascading down one side of the building, which has been open to the public all year-round since October 2019. This purposefully bold design sets out to change people’s perceptions of what power stations can do.

CopenHill ski slope, Amager Bakke, Copenhagen, Denmark. Photos: Max Mestour.

CopenHill ski slope, Amager Bakke, Copenhagen, Denmark. Photos: Max Mestour.

The decommissioning of power stations has resulted in cities’ acquiring buildings in prime central locations for the public to enjoy. These examples demonstrate the world’s transition to renewable power, the advances of technology, and populations’ increasing awareness of the environmental impact of their energy usage.

Top image: Entrance of E-WERK Luckenwalde, 2019. Photo: Ben Westoby. Click here to view/download. 

What is net zero?

21 January 2020

Carbon capture
Skyscraper vertical forest in Milan

For age-old rivals Glasgow and Edinburgh, the race to the top has taken a sharp turn downwards. Instead, they’re in a race to the bottom to earn the title of the first ‘net zero’ carbon city in the UK.

While they might be battling to be the first in the UK to reach net zero, they are far from the only cities with net zero in their sights. In the wake of the growing climate emergency, cities, companies and countries around the world have all announced their own ambitions for hitting ‘net zero’.

It has become a global focus based on necessity – for the world to hit the Paris Agreement targets and limit global temperature rise to under two degrees Celsius, it’s predicted the world must become net zero by 2070.

Yet despite its ubiquity, net zero is a term that’s not always fully understood. So, what does net zero actually mean?

Glasgow, Scotland. Host of COP26.

What does net zero mean?

‘Going net zero’ most often refers specifically to reaching net zero carbon emissions. But this doesn’t just mean cutting all emissions down to zero.

Instead, net zero describes a state where the greenhouse gas (GHG) emitted [*] and removed by a company, geographic area or facility is in balance.

In practice, this means that as well as making efforts to reduce its emissions, an entity must capture, absorb or offset an equal amount of carbon from the atmosphere to the amount it releases. The result is that the carbon it emits is the same as the amount it removes, so it does not increase carbon levels in the atmosphere. Its carbon contributions are effectively zero – or more specifically, net zero.

The Grantham Research Institute on Climate Change and the Environment likens the net zero target to running a bath – an ideal level of water can be achieved by either turning down the taps (the mechanism adding emissions) or draining some of the water from the bathtub (the thing removing of emissions from the atmosphere). If these two things are equally matched, the water level in the bath doesn’t change.

To reach net zero and drive a sustained effort to combat climate change, a similar overall balance between emissions produced and emissions removed from the atmosphere must be achieved.

But while the analogy of a bath might make it sound simple, actually reaching net zero at the scale necessary will take significant work across industries, countries and governments.

How to achieve net zero

The UK’s Committee on Climate Change (CCC) recommends that to reach net zero all industries must be widely decarbonised, heavy good vehicles must switch to low-carbon fuel sources, and a fifth of agricultural land must change to alternative uses that bolster emission reductions, such as biomass production.

However, given the nature of many of these industries (and others considered ‘hard-to-treat’, such as aviation and manufacturing), completely eliminating emissions is often difficult or even impossible. Instead, residual emissions must be counterbalanced by natural or engineered solutions.

Natural solutions can include afforestation (planting new forests) and reforestation (replanting trees in areas that were previous forestland), which use trees’ natural ability to absorb carbon from the atmosphere to offset emissions.

On the other hand, engineering solutions such as carbon capture usage and storage (CCUS) can capture and permanently store carbon from industry before it’s released into the atmosphere. It is estimated this technology can capture in excess of 90% of the carbon released by fossil fuels during power generation or industrial processes such as cement production.

Negative emissions essential to achieving net zero

Click to view/download graphic. Source: Zero Carbon Humber.

Bioenergy with carbon capture and storage (BECCS) could actually take this a step further and lead to a net removal of carbon emissions from the atmosphere, often referred to as negative emissions. BECCS combines the use of biomass as a fuel source with CCUS. When that biomass comes from trees grown in responsibly managed working forests that absorb carbon, it becomes a low carbon fuel. When this process is combined with CCUS and the carbon emissions are captured at point of the biomass’ use, the overall process removes more carbon than is released, creating ‘negative emissions’.

According to the Global CCS Institute, BECCS is quickly emerging as the best solution to decarbonise emission-heavy industries. A joint report by The Royal Academy of Engineering and Royal Society estimates that BECCS could help the UK to capture 50 million tonnes of carbon per year by 2050 – eliminating almost half of the emissions projected to remain in the economy.

The UK’s move to net zero

In June 2019, the UK became the first major global economy to pass a law to reduce all greenhouse gas emissions to net zero by 2050. It is one of a small group of countries, including France and Sweden, that have enacted this ambition into law, forcing the government to take action towards meeting net zero.

Electrical radiator

Although this is an ambitious target, the UK is making steady progress towards it. In 2018 the UK’s emissions were 44% below 1990 levels, while some of the most intensive industries are fast decarbonising – June 2019 saw the carbon content of electricity hit an all-time low, falling below 100 g/kWh for the first time. This is especially important as the shift to net zero will create a much greater demand for electricity as fossil fuel use in transport and home heating must be switched with power from the grid.

Hitting net zero will take more than just this consistent reduction in emissions, however. An increase in capture and removal technologies will also be required. On the whole, the CCC predict an estimated 75 to 175 million tonnes of carbon and equivalent emissions will need to be removed by CCUS solutions annually in 2050 to fully meet the UK’s net zero target.

This will need substantial financial backing. The CCC forecasts that, at present, a net zero target can be reached at an annual resource cost of up to 1-2% of GDP between now and 2050. However, there is still much debate about the role the global carbon markets need to play to facilitate a more cost-effective and efficient way for countries to work together through market mechanisms.

Industries across the UK are starting to take affirmative action to work towards the net zero target. In the energy sector, projects such as Drax Power Station’s carbon capture pilots are turning BECCS increasingly into a reality ready to be deployed at scale.

Along with these individual projects, reaching net zero also requires greater cooperation across the industrial sectors. The Zero Carbon Humber partnership between energy companies, industrial emitters and local organisations, for example, aims to deliver the UK’s first zero carbon industrial cluster in the Humber region by the mid-2020s.

Nonetheless, efforts from all sectors must be made to ensure that the UK stays on course to meet all its immediate and long-term emissions targets. And regardless of whether or not Edinburgh or Glasgow realise their net zero goals first, the competition demonstrates how important the idea of net zero has become and society’s drive for real change across the UK.

Drax has announced an ambition to become carbon negative by 2030 – removing more carbon from the atmosphere than produced in our operations, creating a negative carbon footprint. Track our progress at Towards Carbon Negative.

[*] In this article we’ve simplified our explanation of net zero. Carbon dioxide (CO2) is the most abundant greenhouse gas (GHG). It is also a long-lived GHG that creates warming that persists in the long term. Although the land and ocean absorb it, a significant proportion stays in the atmosphere for centuries or even millennia causing climate change. It is, therefore, the most important GHG to abate. Other long-lived GHGs include include nitrous oxide (N2O, lifetime of circa 120 years) and some F-Gasses (e.g. SF6 with a lifetime of circa 3,200 years). GHGs are often aggregated as carbon dioxide equivalent (abbreviated as CO2e or CO2eq) and it is this that net zero targets measure. In this article, ‘carbon’ is used for simplicity and as a proxy for ‘carbon dioxide’, ‘CO2‘, ‘GHGs’ or ‘CO2e’.