Tag: FAQs (frequently asked questions)

What is the carbon cycle?

25 March 2022

Carbon capture

What is the carbon cycle?

All living things contain carbon and the carbon cycle is the process through which the element continuously moves from one place in nature to another. Most carbon is stored in rock and sediment, but it’s also found in soil, oceans, and the atmosphere, and is produced by all living organisms – including plants, animals, and humans.

Carbon atoms move between the atmosphere and various storage locations, also known as reservoirs, on Earth. They do this through mechanisms such as photosynthesis, the decomposition and respiration of living organisms, and the eruption of volcanoes.

As our planet is a closed system, the overall amount of carbon doesn’t change. However, the level of carbon stored in a particular reservoir, including the atmosphere, can and does change, as does the speed at which carbon moves from one reservoir to another.

What is the role of photosynthesis in the carbon cycle?

Carbon exists in many different forms, including the colourless and odourless gas that is carbon dioxide (CO2). During photosynthesis, plants absorb light energy from the sun, water through their roots, and CO2 from the air – converting them into oxygen and glucose.

The oxygen is then released back into the air, while the carbon is stored in glucose, and used for energy by the plant to feed its stem, branches, leaves, and roots. Plants also release CO2 into the atmosphere through respiration.

Animals – including humans – who consume plants similarly digest the glucose for energy purposes. The cells in the human body then break down the glucose, with CO2 emitted as a waste product as we exhale.

CO2 is also produced when plants and animals die and are broken down by organisms such as fungi and bacteria during decomposition.

What is the fast carbon cycle?

The natural process of plants and animals releasing CO2 into the atmosphere through respiration and decomposition and plants absorbing it via photosynthesis is known as the biogenic carbon cycle. Biogenic refers to something that is produced by or originates from a living organism. This cycle also incorporates CO2 absorbed and released by the world’s oceans.

The biogenic carbon cycle is also called the “fast” carbon cycle, as the carbon that circulates through it does so comparatively quickly. There are nevertheless substantial variations within this faster cycle. Reservoir turnover times – a measure of how long the carbon remains in one location – range from years for the atmosphere to decades through to millennia for major carbon sinks on land and in the ocean.

What is the slow carbon cycle?

In some circumstances, plant and animal remains can become fossilised. This process, which takes millions of years, eventually leads to the formation of fossil fuels. Coal comes from the remains of plants that have been transformed into sedimentary rock. And we get crude oil and natural gas from plankton that once fell to the ocean floor and was, over time, buried by sediment.

The rocks and sedimentary layers where coal, crude oil, and natural gas are found form part of what is known as the geological or slow carbon cycle. From this cycle, carbon is returned to the atmosphere through, for example, volcanic eruptions and the weathering of rocks. In the slow carbon cycle, reservoir turnover times exceed 10,000 years and can stretch to millions of years.

How do humans impact the carbon cycle?

Left to its own devices, Earth can keep CO2 levels balanced, with similar amounts of CO2 released into and absorbed from the air. Carbon stored in rocks and sediment would slowly be emitted over a long period of time. However, human activity has upset this natural equilibrium.

Burning fossil fuel releases carbon that’s been sequestered in geological formations for millions of years, transferring it from the slow to the fast (biogenic) carbon cycle. This influx of fossil carbon leads to excessive levels of atmospheric CO2, that the biogenic carbon cycle can’t cope with.

As a greenhouse gas that traps heat from the sun between the Earth and its atmosphere, CO2 is essential to human existence. Without CO2 and other greenhouse gases, the planet could become too cold to sustain life.

However, the drastic increase in atmospheric CO2 due to human activity means that too much heat is now retained between Earth and the atmosphere. This has led to a continued rise in the average global temperature, a development that is part of climate change.

Where does biomass fit into the carbon cycle?

One way to help reduce fossil carbon is to replace fossil fuels with renewable energy, including sustainably sourced biomass. Feedstock for biomass energy includes plant material, wood, and forest residue – organic matter that absorbs CO2 as part of the biogenic carbon cycle. When the biomass is combusted in energy or electricity generation, the biogenic carbon stored in the organic matter is released back into the atmosphere as CO2.

This is distinctly different from the fossil carbon released by oil, gas, and coal. The addition of carbon capture and storage to bioenergy – creating BECCS – means the biogenic carbon absorbed by the organic matter is captured and sequestered, permanently removing it from the atmosphere. By capturing CO2 and transporting it to geological formations – such as porous rocks – for permanent storage, BECCS moves CO2 from the fast to the slow carbon cycle.

This is the opposite of burning fossil fuels, which takes carbon out of geological formations (the slow carbon cycle) and emits it into the atmosphere (the fast carbon cycle). Because BECCS removes more carbon than it emits, it delivers negative emissions.

Fast facts

  • According to a 2019 study, human activity including the burning of fossil fuels releases between 40 and 100 times more carbon every year than all volcanic eruptions around the world.
  • In March 2021, the Mauna Loa Observatory in Hawaii reported that average CO2 in the atmosphere for that month was 14 parts per million. This was 50% higher than at the time of the Industrial Revolution (1750-1800).
  • There is an estimated 85 billion gigatonne (Gt) of carbon stored below the surface of the Earth. In comparison, just 43,500 Gt is stored on land, in oceans, and in the atmosphere.
  • Forests around the world are vital carbon sinks, absorbing around 7.6 million tonnes of CO2 every year.

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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.

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

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

18 May 2021

Carbon capture

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

Bioenergy with carbon capture and storage (BECCS) is the process of capturing and permanently storing carbon dioxide (CO2) from biomass (organic matter) energy generation.

Why is BECCS important for decarbonisation? 

Bioenergy has very low net carbon emissions when biomass is sustainably sourced from forests that are managed to regrow at least as fast as they are harvested. This means that carbon taken up by the regrowing forests compensates for the carbon released when biomass is combusted.

When sustainable bioenergy is paired with carbon capture and storage it becomes a source of negative emissions, as CO2 is permanently removed from the carbon cycle.

Experts believe that negative emissions technologies (NETs) are crucial to helping countries meet the long-term goals set out in the Paris Climate Agreement. As BECCS is the most scalable of these technologies this decade, it has a key role to play in combating climate change.

How is the bioenergy for BECCS generated?

Most bioenergy is produced by combusting biomass as a fuel in boilers or furnaces to produce high-pressure steam that drives electricity-generating turbines. Alternatively, bioenergy generation can use a wide range of organic materials, including crops specifically planted and grown for the purpose, as well as residues from agriculture, forestry and wood products industries. Energy-dense forms of biomass, such as compressed wood pellets, enable bioenergy to be generated on a much larger scale. Fuels like wood pellets can also be used as a substitute for coal in existing power stations.

How is the carbon captured?

BECCS uses a post-combustion carbon capture process, where solvents isolate CO2 from the flue gases produced when the biomass is combusted. The captured CO2 is pressurised and turned into a liquid-like substance so it can then be transported by pipeline.

How is the carbon stored?

Captured CO2 can be safely and permanently injected into naturally occurring porous rock formations, for example unused natural gas reservoirs, coal beds that can’t be mined, or saline aquifers (water permeable rocks saturated with salt water). This process is known as sequestration.

Over time, the sequestered CO2 may react with the minerals, locking it chemically into the surrounding rock through a process called mineral storage.

BECCS fast facts

  • Two 600+ megawatt (MW) biomass units, upgraded with carbon capture technology, could deliver 40% of the negative emissions the Climate Change Committee indicates will be needed from BECCS for the UK to reach net-zero by 2050
  • BECCS has the potential to remove 20-70 million tonnes of CO2 per year in the UK by 2050
  • All National Grid’s Net Zero Future Energy Scenarios (FES) deploy BECCS by 2028 and see a rapid increase in capacity in the 2030s
  • There are 70 billion tonnes of potential CO2 storage space around the UK, according to the British Geological Survey

Is BECCS sustainable?

 Bioenergy can be generated from a range of biomass sources ranging from agricultural by-products to forestry residues to organic municipal waste. During their lifetime plants absorb CO2 from the atmosphere, this balances out the CO2that is released when the biomass is combusted.

What’s crucial is that the biomass is sustainably sourced, be it from agriculture or forest waste. Responsibly managed sources of biomass are those which naturally regenerate or are replanted and regrown, where there’s a increase of carbon stored in the land and where the natural environment is protected from harm.

Biomass wood pellets used as bioenergy in the UK, for example, are only sustainable when the forests they are sourced from continue to grow. Sourcing decisions must be based on science and not adversely affect the long-term potential of forests to store and sequester carbon.

Biomass pellets can also create a sustainable market for forestry products, which serves to encourage reforestation and afforestation – leading to even more CO2 being absorbed from the atmosphere.

Go deeper:

  • The triple benefits for the environment and economy of deploying BECCS in the UK.
  • How BECCS can offer essential grid stability as the electricity system moves to low- and zero-carbon sources.
  • Producing biomass from sustainable forests is key to ensuring BECCS can deliver negative emissions.
  • 5 innovative projects where carbon capture is already underway around the world
  • 7 places on the path to negative emissions through BECCS

What is a biomass wood pellet?

22 January 2021

Sustainable bioenergy

However, by compressing organic matter like wood, forest residues and sawdust into energy-dense pellets, biomass can be used for heating or renewable bioenergy generation at a much greater scale.

Why are pellets powerful?

The advantage of using biomass in the form of a pellet is its energy density. This refers to the amount of energy that can be stored in a given amount of a material.

On their own the wood and residues like wood chips and sawdust that make up biomass do not have a high energy density. A kilogram of wood, for example, stores little energy, compared to fuels like coal, diesel or uranium.

However, by compressing forest industry residues into a pellet, biomass becomes significantly more energy dense. Wood pellets can also have very low moisture content, giving them a high combustion efficiency – an important feature in power generation.

How are biomass pellets made?

Biomass pellets are made at a pelletisation plant. Here wood that is unsuitable for other industries like sawmill residues, are brought together.

The wood is chipped, screened for quality, heated to reduce its moisture content to below 12% and then converted into a fine powder. This is then pressed through a grate at high pressure to form the solid, short, dense biomass pellet.

How are pellets used in power generation?

Biomass pellets can be used to generate power in a similar way to coal, allowing existing coal power stations to be transformed to use renewable bioenergy instead.

A conveyor system takes pellets from storage through to pulverising mills, where they are crushed into a fine powder that is then blown into the power station’s boiler. Here the biomass is combusted as fuel, the heat from this combustion is used to make steam which powers the generators that produce electricity.

Biomass pellets’ density and uniform shape also makes them easier to transport and store in large quantities. However, it is essential that they are kept dry while in transit and that when stored in biomass domes the atmospheric conditions are carefully monitored and controlled to prevent unwanted combustion.

Biomass pellet facts

Are biomass pellets renewable? 

When forests are sustainably managed, and trees naturally regenerated or replanted and regrown in a human timeframe, it makes the biomass pellets sourced from them renewable.

It’s vital for the long-term energy generation that biomass pellets are sourced from responsibly managed forests and other industries that protect the environment and do not contribute to deforestation. Sourcing decisions must be science-based and not adversely affect the long-term potential of forests to store and sequester carbon.

Sustainable wood pellets are considered to be carbon neutral at the point of combustion. As they grow, forests absorb carbon from the atmosphere. When a biomass pellet is combusted, the same amount of atmospheric CO2 is released. The overall amount of CO2 in the atmosphere remains neutral, unlike with fossil fuels which release ancient carbon that has long fallen out of the natural carbon cycle.

Because sustainable bioenergy is low carbon when its lifecycle emissions, including supply chain CO2, are factored in, it is possible to turn it into a source of negative emissions, with the addition of carbon capture technology.

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What is electricity trading?

29 December 2020

Power generation

What is electricity trading?

Electricity trading is the process of power generators selling the electricity they generate to power suppliers, who can then sell this electricity on to consumers. The system operator – National Grid ESO in Great Britain – oversees the flow of electricity around the country, and ensures the amounts traded will ultimately meet demand and do not overwhelm the power system.

Who is involved in electricity trading?

There are three main parties in a power market: generators (thermal power plants and energy storage sites, sources such as wind turbines and solar panels producing electricity), consumers (hospitals, transport, homes and factories using electricity), and suppliers in the middle from whom you purchase electricity.

Electricity is generated at power stations, then bought by suppliers, who then sell it on to meet the needs of the consumers.

Electricity trading refers to the transaction between power generators, who produce electricity, and power suppliers, who sell it on to consumers.

How are electricity contracts made?

Electricity trading occurs in both long- and short-term time frames, ranging from years in advance to deals covering the same day. Generation and supply must meet exact demand for every minute of the day, which means that traders must always be ready to buy or sell power to fill any sudden gaps that arise.

When trading electricity far in advance, factors such as exchange rates, the cost and availability of fuel, changing regulations and policies all affect the price. Short-term price is more volatile, and factors such as weather, news events and even what’s on television having the biggest impact on price. 

Traders analyse live generation data and news reports, to predict ahead of time how much electricity will be needed during periods of high demand and then determine a price. Traders then make offers and bids to suppliers and strike a deal – these deals then dictate how and when a power station’s generators are run every day.

Why is electricity trading important?

Running a power station is an expensive process and demand for electricity never stops.  The electricity market ensures the country’s power demands are met, while also aiming to keep electricity businesses sustainable, through balancing the price of buying raw materials with the price at which electricity is sold.

To ensure the grid remains balanced and meets demand, the systems operator also makes deals with generators for ancillary services, either far in advance, or last-minute. This ensures elements such as frequency, voltage and reserve power are kept stable across the country and that the grid remains safe and efficient.

Electricity trading ensures there is always a supply of power and that the market for electricity operates in a stable way

Electricity trading fast facts  

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What is renewable energy?

17 December 2020

Sustainable bioenergy

These differ to non-renewable energy sources such as coal, oil and natural gas, of which there is a finite amount available on Earth, meaning if used excessively they could eventually run out.

Renewable resources can provide energy for a variety of applications, including electricity generation, transportation and heating or cooling.

The difference between low-carbon, carbon neutral and renewable energy

Renewables such as wind, solar and hydropower are zero carbon sources of energy because they do not produce any carbon dioxide (CO2) when they generate power. Low-carbon sources might produce someCO2, but much less than fuels like coal.

Bioenergy that uses woody biomass from sustainably managed forests to generate electricity is carbon neutral because forests absorb CO2 from the atmosphere as they grow, meaning the amount of CO2 in the atmosphere remains level. Supply chains that bring bioenergy to power stations commonly use some fossil fuels in manufacturing and transportation. Therefore woody biomass is a low carbon fuel, when its whole lifecycle is considered.

Managing forests in a sustainable way that does not lead to deforestation allows bioenergy to serve as a renewable source of power. Responsible biomass sourcing also helps forests to absorb more carbon while displacing fossil fuel-based energy generation.

Nuclear is an example of a zero carbon source of electricity that is not renewable. It does not produce CO2,but it is dependent on uranium or plutonium, of which there is a finite amount available.

Managing forests in a sustainable way that does not lead to deforestation allows bioenergy to serve as a renewable source of power.

How much renewable energy is used around the world?

Humans have harnessed renewable energy for millions of years in the form of woody biomass to fuel fires, as well as wind to power ships and geothermal hot springs for bathing. Water wheels and windmills are other examples of humans utilising renewable resources, but since the industrial revolution fossil fuels, coal in particular, have been the main source of power.

However, as the effects of air pollution and CO2 produced from burning fossil fuels become increasingly apparent, renewable energy is gradually replacing sources which contribute to climate change.

In the year 2000 renewable energy accounted for 18% of global electricity generation, according to the IEA. By 2019, renewable sources made up 27% of the world’s electrical power.

Why renewable energy is essential to tackling climate change

The single biggest human contribution to climate change is greenhouse gas emissions, such as CO2, into the atmosphere. They create an insulating layer around the planet that causes temperatures on Earth to increase, making it less habitable.

Renewable sources of electricity can help to meet the world’s demand for power without contributing to global warming, unlike carbon-intensive fuels like coal, gas and oil.

Bioenergy can also be used to remove CO2 from the atmosphere while delivering renewable electricity through a process called bioenergy with carbon capture and storage (BECCS).

Forests absorb CO2 from the atmosphere, then when the biomass is used to generate electricity the same CO2 is captured and stored permanently underground – reducing the overall amount of CO2 in the atmosphere.

Humans have used renewable energy for millions for years, from wood for fires to wind powering boats to geothermal hot springs. 

What’s holding renewables back?

The world’s energy systems were built with fossil fuels in mind. This can make converting national grids difficult and installing new renewable energy sources expensive. However, as knowledge grows about how best to manufacture, build and operate renewable systems, the cost of deploying them at scale drops.

There are future changes needed. Renewables such as wind, solar and tidal power are known as intermittent renewables because they can’t generate electricity when there is no sun, wind or the tidal movement. For future energy systems to deliver enough power, large scale energy storage, as well as other flexible, reliable forms of generation will also be needed to meet demand and keep systems stable.

Renewable energy key facts:  

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What is carbon dioxide?

18 September 2020

Carbon capture

What is CO2?

Carbon dioxide (or CO2) is a colourless and odourless naturally occurring gas in the earth’s atmosphere which is made up of one carbon atom and two oxygen atoms.  As a greenhouse gas (GHG), it traps heat, making sure the planet isn’t uninhabitably cold. However, fast rising levels of CO2 and other long-lasting GHGs in the atmosphere are currently causing global warming to occur at an alarmingly rapid rate.

What is the carbon cycle?

Carbon is the basis of all life on earth – it is a key ingredient in almost everything on the planet. As the earth has a closed atmosphere, there has always been the same amount of carbon on the earth, but it is in a constant state of change, transitioning from gas to solid to liquid and moving between the atmosphere and the earth. This process is called the carbon cycle, and it is key to ensuring the earth is capable of sustaining life. CO2 forms one part of this process and makes up the largest available source of carbon on earth.

How is CO2 made?

Carbon is stored in oceans, soil, and living things and is released from this storage into the atmosphere in the form of CO2. CO2 is created when one carbon atom meets two oxygen atoms, which join together through a number of processes, including the decay of organic matter, the combustion of materials such as wood, coal and natural gas, through the breathing of humans and animals, and from events such as volcanic eruptions.

How does CO2 affect the planet?

An abundance of CO2 in the earth’s atmosphere means more heat gets trapped, which in turn contributes to a rise in global temperatures and climate change. This acceleration in carbon entering the atmosphere began during the Industrial Revolution around the 1800s, when fossil fuels were mined and burned to create energy, which released long-stored carbon into the atmosphere in the form of CO2.

From the beginning of the Industrial Revolution until today, the amount of carbon in the atmosphere has increased from 280 parts per million, to 387 parts per million, which constitutes a 39% increase. Today, CO2 levels are the highest they’ve been in 800,000 years.

CO2 is created when one carbon atom meets two oxygen atoms, which join together when organic materials containing carbon are burned: wood, coal, and natural gas.

How can countries reduce CO2 in the atmosphere?

According to the Paris Climate Agreement, nations must work to limit warming of the globe to be well under two degrees Celsius above pre-industrial levels. In the first half of 2015, the earth registered a one degree Celsius rise in global temperatures above pre-industrial levels, which means drastic and meaningful action must be taken to decarbonise within the next few years.

There are many ways to reduce the earth’s carbon footprint, including reforestation and using alternative ways to generate energy that don’t rely on fossil fuels. For example, wind, solar, biomass and hydro can all provide sustainable, carbon-neutral and low carbon sources of electricity.

Technology such as carbon capture and storage (CCS) can capture carbon permanently storing CO2 from industries in which some CO2 emissions remain. By combining CCUS with biomass energy (bioenergy with carbon capture and storage, or BECCS) it is even possible to generate negative emissions, where more CO2 is removed from the atmosphere than is emitted.

CO2 fast facts

  • In the 1960s, the growth of CO2 occurred at 0.6 parts per million per year. In the last 10 years, the rate has been 2.3 parts per million per year
  • The average human breathes out 93 kilograms of CO2 per year – however, our breathing only contributes 0.65 billion tonnes of carbon returned to the atmosphere, which is 0.01% of the amount released by fossil fuels each year
  • Trees absorb CO2 in the atmosphere and release it in the form of oxygen, making them vitally important in the world’s fight against climate change. In the US alone, forests absorb 13% of the nation’s carbon output

There are many ways to reduce the earth’s carbon footprint, including using alternative ways to generate power.

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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

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What is biomass?

Sustainable bioenergy
Illustration of a working forest supplying biomass

What is biomass?

In ecological terms, biomass refers to any type of organic matter. When it comes to energy, biomass is any organic matter that can be used to generate energy, for example wood, forest residues or plant materials.

How is biomass used?  

Biomass used and combusted for energy can come in a number of different forms, ranging from compressed wood pellets – which are used in power stations that have upgraded from coal – to biogas and biofuels, a liquid fuel that can be used to replace fossil fuels in transport.

The term biomass also refers to any type of organic material used for energy in domestic settings, for example wood burned in wood stoves and wood pellets used in domestic biomass boilers.

Biomass is organic matter like wood, forest residues or plant material, that is used to generate energy.

Where does biomass come from?

Biomass can be produced from different sources including agricultural or forestry residues, dedicated energy crops or waste products such as uneaten food.

Drax Power Station uses compressed wood pellets sourced from sustainably managed working forests in the US, Canada, Europe and Brazil, and are largely made up of low-grade wood produced as a byproduct of the production and processing of higher value wood products, like lumber and furniture.

Biomass producers and users must meet a range of stringent measures for their biomass to be certified as sustainable and responsibly sourced.

Key biomass facts

Is biomass renewable?

 Biomass grown through sustainable means is classified as a renewable source of energy because of the process of its growth. As biomass comes from organic, living matter, it grows naturally, absorbing carbon dioxide (CO2) from the atmosphere in the process.

It means when biomass is combusted as a source of energy – for example for heat or electricity production – the CO2 released is offset by the amount of CO2 it absorbed from the atmosphere while it was growing.

Fast facts

  • In 2019 biomass accounted for 6% of Great Britain’s electricity generation, more than 1/6 of the total generation of all renewable sources
  • There is about 550 gigatonnes of biomass carbon on Earth in total. Humans make up around 1/10,000th of that mass.
  • Modern biomass was first developed as an alternative for oil after its price spiked as a result of the 1973 Yom Kippur War
  • The International Energy Agency (IEA) estimates bioenergy accounts for roughly 1/10th of the world’s total energy supply

Biomass is a renewable, sustainable form of energy used around the world.

How long has biomass been used as a source of energy?

Biomass has been used as a source of energy for as long as humans have been creating fire. Early humans using wood, plants or animal dung to make fire were all creating biomass energy.

Today biomass in the form of wood and wood products remains a widely used energy source for many countries around the world – both for domestic consumption and at grid scale through power stations, where it’s often used to replace fossil fuels with much higher lifecycle carbon emissions.

Drax Power Station has been using compressed wood pellets (a form of biomass) since 2003, when it began research and development work co-firing it with coal. It fully converted its first full generating unit to run only on compressed wood pellets in 2013, lowering the carbon footprint of the electricity it produced by more than 80% across the renewable fuel’s lifecycle. Today the power station runs mostly on sustainable biomass.

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Read next: What is reforestation and afforestation?