Tag: decarbonisation

An introduction to carbon accounting

12 May 2022

Sustainable business

Key takeaways:

  • Tracking, reporting, and calculating carbon emissions are a key part of progressing countries, industries, and companies towards net zero goals.
  • As a newly established discipline, carbon accounting still lacks standardisation and frameworks in how emissions are tracked, reduced, and mitigated.
  • The main carbon accounting standard used by businesses is the Greenhouse Gas (GHG) Protocol, which lays out three ‘Scopes’ businesses should report and act upon.
  • Carbon accounting evolves from reporting in the use of goals and timeframes in which targets are met.
  • Timeframes are crucial in the deployment of technologies like carbon capture, removals, and achieving net zero.

How can countries and companies find a route to net zero emissions? Many organisations, countries and industries have pledged to balance their emissions before mid-century. They intend to do this through a combination of cutting emissions and removing carbon from the atmosphere.

Tracking and quantifying emissions, understanding output, reducing them, and setting tangible targets that can be worked towards are all central to tackling climate change and reducing greenhouse gas emissions – especially when it comes to carbon dioxide (CO2). Emissions and energy consumption reporting is already common practice and compulsory for businesses over a certain size in the UK. However, carbon accounting takes this a step further.

“Carbon reporting is a statement of physical greenhouse gas emissions that occur over a given period,” explains Michael Goldsworthy, Head of Climate Change and Carbon Strategy at Drax. “Carbon accounting relates to how those emissions are then processed and counted towards specific targets. The methodologies for calculating emissions and determining contributions against targets may then have differing rules depending on which framework or standard is being reported against.”

Carbon accounting tools can help companies and counties understand their carbon footprint – how much carbon is being emitted as part of their operations, who is responsible for them, and how they can be effectively mitigated.

Like how financial accounting may seek to balance a company’s books and calculate potential profit, carbon accounting seeks to do the same with emissions, tracking what an entity emits, and what it reduces, removes, or mitigates. Carbon accounting is, therefore, crucial in understanding how countries and companies can contribute to reaching net zero.

A new space

How different organisations, countries and industries approach carbon accounting is still an evolving process.

“It’s as complex as financial accounting, but with financial accounting, there’s a long standing industry that relies on well-established practices and principles. Carbon accounting by contrast is such a new space,” explains Goldsworthy.

Regardless of its infancy, businesses and countries are already implementing standardised approaches to carbon accounting. Regulations such as emissions trading schemes and reporting systems, such as Streamlined Energy and Carbon Reporting (SECR) and the Taskforce on Climate Related Financial Disclosure (TCFD), are beginning to deliver some degree of consistency in businesses’ carbon reporting.

Other standards such as the GHG Protocol have sought to provide a standardised basis for corporate reporting and accounting. Elsewhere, voluntary carbon markets (e.g. carbon offsets) have also evolved to allow transferral of carbon reductions or removals between businesses, providing flexibility to companies in delivering their climate commitments.

The challenge is in aligning these frameworks so that they work together. For example, emissions within a corporate inventory or offset programme must be accounted for in a way that is consistent with a national inventory.

To date, these accounting systems have evolved independently with different rules and methodologies. Beginning to implement detailed carbon accounting, upon which emissions reductions and removals can be based, requires standardised understanding of what they are and where they come from.

Reporting and tackling Scope One, Two, and Three emissions

The main carbon accounting standard used by businesses is the Greenhouse Gas (GHG) Protocol. This voluntary carbon reporting standard can be used by countries and cities, as well as individual companies globally.

The GHG protocol categorises emissions in three different ‘scopes’, called Scope 1, Scope 2, and Scope 3. Understanding, measuring, and reporting these is a key factor in carbon accounting and can drive meaningful emissions reduction and mitigation.

Scope One – Direct emissions

Scope One emissions are those that come as a direct result of a company or country’s activities. These can include fuel combustion at a factory’s facilities, for example, or emissions from a fleet of vehicles.

Scope One emissions are the most straightforward for an organisation to measure and report, and easier for organisations to directly act on.

Scope Two – Indirect energy emissions

Scope Two emissions are those which come from the generation of energy an organisation uses. These can include emissions form electricity, steam, heating, and cooling.

A business may buy electricity, for example, from an electricity supplier, which acquires power from a generator. If that generator is a fossil-fuelled power station the energy consumer’s Scope Two emissions will be greater than if it buys power from a renewable electricity supplier or generates its own renewable power.

The ability to change energy suppliers makes Scope Two relatively straightforward for organisations to act on, assuming renewable energy sources are available in the area.

Scope Three – All other indirect emissions

Scope Three is much broader. It covers upstream and downstream lifecycle emissions of products used or produced by a company, as well as other indirect emissions such as employee commuting and business travel emissions.

Identifying and reducing these emissions across supply and value chains can be difficult for businesses with complex supply lines and global distribution networks. They are also hard for companies to directly influence.

Add in factors like emissions mitigations or offsetting, and the carbon accounting can quickly become much more complex than simply reporting and reducing emissions that occur directly from a company’s activities. Nevertheless, these full-system overviews and whole-product lifecycle accounting are crucial to understanding the true impact of operations and organisations, and to reach climate goals.

Working to timelines

Setting goals with defined timelines and the development of rules that ensure consistent accounting is also crucial to implementing effective climate change mitigation frameworks throughout the global economy. Consider the UK’s aim to be net zero by 2050, or Drax’s ambition to be net negative by 2030, as goals with set timelines.

For many technologies, the time scales over which targets are set have added relevance. There are often upfront emissions to account for and operational emissions that may change over time. Take for example an electric vehicle: the climate benefit will be determined by emissions from construction and the carbon intensity of the electricity used to power it.

A timeline of BECCS at Drax [click to view/download]

Looking at a brief snapshot at the beginning of its life, say the first couple of years, might not show any climate benefit compared to a vehicle using an internal combustion engine. Over the lifetime of the vehicle, however, meaningful emissions savings may become clear – especially if the electricity powering the vehicle continues to decarbonise over time.

This provides a challenge when setting carbon emissions targets. Targets set too far in the future potentially risk inaction in the short term, while targets set over short periods risk disincentivising technologies that have substantial long-term mitigation potential. 

Delivering net zero

Some greenhouse gas emissions will be impossible to fully abate, such as methane and nitrous oxide emissions from agriculture, while other sectors, like aviation, will be incredibly difficult to fully decarbonise. This makes carbon removal technologies all the more critical to ensuring net zero is achieved.

Technologies such as bioenergy with carbon capture and storage (BECCS) – which combines low-carbon, biomass-fuelled renewable power generation with carbon capture and storage (CCS) to permanently remove emissions from the atmosphere – are already under development.

However, it is imperative that such technologies are accounted for using robust approaches to carbon accounting, ensuring all emission and removals flows across the value chain are accurately calculated in accordance with best scientific practice. In the case of BECCS, it’s vital that not only are emissions from processing and transporting biomass considered, but also its potential impact on the land sector.

Forests from which biomass is sourced will be managed for a variety of reasons, such as mitigating natural disturbance, delivering commercial returns, and preserving ecosystems. Accurate accounting of these impacts is therefore key to ensuring such technologies deliver meaningful reductions in atmospheric CO2within timeframes guided by science.

Accounting for net zero

While carbon accounting is crucial to reaching a true level of net zero in the UK and globally, where residual emissions are balanced against removals, the practice should not be used exclusively to deliver numerical carbon goals.

“To deliver net zero, it’s vital we have robust carbon accounting systems and targets in place, ensuring we reduce fossil emissions as far as possible while also incentivising carbon removal solutions,” says Goldsworthy.

“However, many removal solutions rely on the natural world and so it is critical that ecosystems are not only valued on a carbon basis but consider other environmental factors such as biodiversity as well.”

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.

Go deeper

Forests, net zero and the science behind biomass

22 December 2021

Sustainable bioenergy

Tackling climate change and spurring a global transition to net zero emissions will require collaboration between science and industry. New technologies and decarbonisation methods must be rooted in scientific research and testing.

Drax has almost a decade of experience in using biomass as a renewable source of power. Over that time, our understanding around the effectiveness of bioenergy, its role in improving forest health and ability to deliver negative emissions, has accelerated.

Research from governments and global organisations, such as the UN’s Intergovernmental Panel on Climate Change (IPCC) increasingly highlight sustainably sourced biomass and bioenergy’s role in achieving net zero on a wide scale.

The European Commission has also highlighted biomass’ potential to provide a solution that delivers both renewable energy and healthy, sustainably managed forests.  Frans Timmermans, the executive vice-president of the European Commission in charge of the European Green Deal has emphasised it’s importance in bringing economies to net zero, saying: “without biomass, we’re not going to make it. We need biomass in the mix, but the right biomass in the mix.”

The role of biomass in a sustainable future

Moving away from fossil fuels means building an electricity system that is primarily based on renewables. Supporting wind and solar, by providing electricity at times of low sunlight or wind levels, will require flexible sources of generation, such as biomass, as well as other technologies like increased energy storage.

In the UK, the Climate Change Committee’s (CCC) Sixth Carbon Budget report lays out its Balanced Net Zero Pathway. In this lead scenario, the CCC says that bioenergy can reduce fossil emissions across the whole economy by 2 million tonnes of CO2 or equivalent emissions (MtCO2e) per year by 2035, increasing to 2.5 MtCO2e in 2045.

Foresters in working forest, Mississippi

Foresters in working forest, Mississippi

Biomass is also expected to play a crucial role in supplying biofuels and hydrogen production for sectors of the global economy that will continue to use fuel rather than electricity, such as aviation, shipping and industrial processes. The CCC’s Balanced Net Zero Pathway suggest that enough low-carbon hydrogen and bioenergy will be needed to deliver 425 TWh of non-electric power in 2050 – compared to the 1,000 TWh of power fossil fuels currently provide to industries today.

However, bioenergy can only be considered to be good for the climate if the biomass used comes from sustainably managed sources. Good forest management practises ensure that forests remain sustainable sources of woody biomass and effective carbon sinks.

A report co-authored by IPCC experts examines the scientific literature around the climate effects (principally CO2 abatement) of sourcing biomass for bioenergy from forests managed according to sustainable forest management principles and practices.

The report highlights the dual impact managed forests contribute to climate change mitigation by providing material for forest products, including biomass that replace greenhouse gas (GHG)-intensive fossil fuels, and by storing carbon in forests and in long-lived forest products.

The role of biomass and bioenergy in decarbonising economies goes beyond just replacing fossil fuels. The addition of carbon capture and storage (CCS) to bioenergy to create bioenergy with carbon capture and storage (BECCS) enables renewable power generation while removing carbon from the atmosphere and carbon cycle permanently.

The negative emissions made possible by BECCS are now seen as a fundamental part of many scenarios to limit global warming to 1.5oC above pre-industrial levels.

BECCS and the path to net zero

The IPCC’s special report on limiting global warming to 1.5oC above pre-industrial levels, emphasises that even across a wide range of scenarios for energy systems, all share a substantial reliance on bioenergy – coupled with effective land-use that prevents it contributing to deforestation.

The second chapter of the report deals with pathways that can bring emissions down to zero by the mid-century. Bioenergy use is substantial in 1.5°C pathways with or without CCS due to its multiple roles in decarbonising both electricity generation and other industries that depend on fossil fuels.

However, it’s the negative emissions made possible by BECCS that make biomass  instrumental in multiple net zero scenarios. The IPCC report highlights BECCS alongside the associated afforestation and reforestation (AR), that comes with sustainable forest management, are key components in pathways that limit climate change to 1.5oC.

Graphic showing how BECCS removes carbon from the atmosphere. Click to view/download

There are two key factors that make BECCS and other forms of emissions removals so essential: The first is their ability to neutralise residual emissions from sources that are not reducing their emissions fast enough and those that are difficult or even impossible to fully decarbonise. Aviation and agriculture are two sectors vital to the global economy with hard-to-abate emissions. Negative emissions technologies can remove an equivalent amount of CO2 that these industries produce helping balance emissions and progressing economies towards net zero.

The second reason BECCS and other negative emissions technologies will be so important in the future is in the removal of historic CO2 emissions. What makes CO2 such an important GHG to reduce and remove is that it lasts much longer in the atmosphere than any other. To help reach the Paris Agreement’s goal of limiting temperature rises to below 1.5oC removing historic emissions from the atmosphere will be essential.

In the UK, the  CCC’s 2018 report ‘Biomass in a low-carbon economy’ also points to BECCS as both a crucial source of energy and emissions abatement.

It suggests that power generation from BECCS will increase from 3 TWh per year in 2035 to 45 TWh per year in 2050. It marks a sharp increase from the 19.5 TWh that biomass (without CCS) accounted for across 2020, according to Electric Insights data. It also suggests that BECCS could sequester 1.1 tonnes of CO2 for every tonne of biomass used, providing clear negative emissions.

However, the report makes clear that unlocking the potential of bioenergy and BECCS is only possible when biomass stocks are managed in a sustainable way that, as a minimum requirement, maintains the carbon stocks in plants and soils over time.

With increased attention paid to forest management and land use, there is a growing body of evidence that points to bioenergy as a win-win solution that can decarbonise power and economies, while supporting healthy forests that effectively sequester CO2.

How bioenergy ensures sustainable forests

Biomass used in electricity generation and other industries must come from sustainable sources to offer a renewable, climate beneficial [or low carbon] source of power.

UK legislation on biomass sourcing states that operators must maintain an adequate inventory of the trees in the area (including data on the growth of the trees and on the extraction of wood) to ensure that wood is extracted from the area at a rate that does not exceed its long-term capacity to produce wood. This is designed to ensure that areas where biomass is sourced from retain their productivity and ability to continue sequestering carbon.

Ensuring that forestland remains productive and protected from land-use changes, such as urban creep, where vegetated land is converted into urban, concreted spaces, depends on a healthy market for wood products. Industries such as construction and furniture offer higher prices for higher-quality wood. While low-quality, waste wood, as well as residues from forests and wood-industry by-products, can be bought and used to produce biomass pellets.

A report by Forest 2 Market examined the relationship between demand for wood and forests’ productivity and ability to sequester carbon in the US South, where Drax sources about two-thirds of its biomass.

The report found that increased demand for wood did not displace forests in the US South. Instead, it encouraged landowners to invest in productivity improvements that increased the amount of wood fibre and therefore carbon contained in the region’s forests.

A synthesis report, which examines a broad range of research papers,  published in Forest Ecology and Management in March of 2021, concluded from existing studies that claims of large-scale damage to biodiversity from woody biofuel in the South East US are not supported. The use of these forest residues as an energy source was also found to lead to net GHG greenhouse emissions savings compared to fossil fuels, according to Forest Research.

Importantly the research shows that climate risks are not exacerbated because of biomass sourcing; in fact, the opposite is true with annual wood growth in the US South increasing by 112% between 1953 and 2015.

Delivering a “win-win solution”

The European Commission’s JRC Science for Policy literature review and knowledge synthesis report ‘The use of woody biomass for energy production in the EU’ suggests  a win-win forest bioenergy pathway is possible, that can reduce greenhouse gas emissions in the short term, while at the same time not damaging, or even improving, the condition of forest ecosystems.

However, it also makes clear “lose-lose” situations is also a possible, in which forest ecosystems are damaged without providing carbon emission reductions in policy-relevant timeframes.

Win-win management practices must benefit climate change mitigation and have either a neutral or positive effect on biodiversity. A win-win future would see the afforestation of former arable land with diverse and naturally regenerated forests.

The report also warns of trade-offs between local biodiversity and mitigating carbon emissions, or vice versa. These must be carefully navigated to avoid creating a lose-lose scenario where biodiversity is damaged and natural forests are converted into plantations, while BECCS fails to deliver the necessary negative emissions.

In a future that will depend on science working in collaboration with industries to build a net zero future continued research is key to ensuring biomass can deliver the win-win solution of renewable electricity with negative emissions while supporting healthy forests.

Transporting carbon – How to safely move CO2 from the atmosphere to permanent storage

15 October 2021

Carbon capture

Key points

  • Carbon capture usage and storage (CCUS) offers a unique opportunity to capture and store the UK’s emissions and help the country reach its climate goals.
  • Carbon dioxide (CO2) can be stored in geological reservoirs under the North Sea, but getting it from source to storage will need a large and safe CO2 transportation network.
  • The UK already has a long history and extensive infrastructure for transporting gas across the country for heating, cooking and power generation.
  • This provides a foundation of knowledge and experience on which to build a network to transport CO2.

Across the length of the UK is an underground network similar to the trainlines and roadways that crisscross the country above ground. These pipes aren’t carrying water or broadband, but gas. Natural gas is a cornerstone of the UK’s energy, powering our heating, cooking and electricity generation. But like the country’s energy network, the need to reduce emissions and meet the UK’s target of net zero emissions by 2050 is set to change this.

Today, this network of pipes takes fossil fuels from underground formations deep beneath the North Sea bed and distributes it around the UK to be burned – producing emissions. A similar system of subterranean pipelines could soon be used to transport captured emissions, such as CO2, away from industrial clusters around factories and power stations, locking them away underground, permanently and safely.

Conveyer system at Drax Power Station transporting sustainable wood pellets

The rise of CCUS technology is the driving force behind CO2 transportation. The process captures CO2 from emissions sources and transports it to sites such as deep natural storage enclaves far below the seabed.

Bioenergy with carbon capture and storage (BECCS) takes this a step further. BECCS uses sustainable biomass to generate renewable electricity. This biomass comes from sources, such as forest residues or agricultural waste products, which remove CO2 from the atmosphere as they grow. Atmospheric CO2 released in the combustion of the biomass is then captured, transported and stored at sites such as deep geological formations.

Across the whole BECCS process, CO2 has gone from the atmosphere to being permanently trapped away, reducing the overall amount of CO2 in the atmosphere and delivering what’s known as negative emissions.

BECCS is a crucial technology for reaching net zero emissions by 2050, but how can we ensure the CO2 is safely transported from the emissions source to storage sites?

Moving gases around safely

Moving gases of any kind through pipelines is all about pressure. Gases always travel from areas of high pressure to areas of low pressure. By compressing gas to a high pressure, it allows it to flow to other locations. Compressor stations along a gas pipeline help to maintain right the pressure, while metering stations check pressure levels and look out for leaks.

The greater the pressure difference between two points, the faster gases will flow. In the case of CO2, high absolute pressures also cause it to become what’s known as a supercritical fluid. This means it has the density of a liquid but the viscosity of a gas, properties that make it easier to transport through long pipelines.

Since 1967 when North Sea natural gas first arrived in the UK, our natural gas transmission network has expanded considerably, and is today made up of almost 290,000 km of pipelines that run the length of the country. Along with that physical footprint is an extensive knowledge pool and a set of well-enforced regulations monitoring their operation.

While moving gas through pipelines across the country is by no means new, the idea of CO2 transportation through pipelines is. But it’s not unprecedented, as it has been carried out since the 1980s at scale across North America. In contrast to BECCS, which would transport CO2 to remove and permanently store emissions, most of the CO2 transport in action today is used in oil enhanced recovery – a means of ejecting more fossil fuels from depleted oil wells. However, the principle of moving CO2 safely over long distances remains relevant – there are already 2,500 km of pipelines in the western USA, transporting as much as 50 million tonnes of CO2 a year.

“People might worry when there is something new moving around in the country, but the science community doesn’t have sleepless nights about CO2 pipelines,” says Dr Hannah Chalmers, from the University of Edinburgh. “It wouldn’t explode, like natural gas might, that’s just not how the molecule works. If it’s properly installed and regulated, there’s no reason to be concerned.”

CO2 is not the same as the methane-based natural gas that people use every day. For one, it is a much more stable, inert molecule, meaning it does not react with other molecules, and it doesn’t fuel explosions in the same way natural gas would.

CO2 has long been understood and there is a growing body of research around transporting and storing it in a safe efficient way that can make CCUS and BECCS a catalyst in reducing the UK’s emissions and future-proofing its economy.

Working with CO2 across the UK

Working with CO2 while it is in a supercritical state mean it’s not just easier to move around pipes. In this state CO2 can also be loaded onto ships in very large quantities, as well as injected into rock formations that once trapped oil and gas, or salt-dense water reserves.

Decades of extracting fossil fuels from the North Sea means it is extensively mapped and the rock formations well understood. The expansive layers of porous sandstone that lie beneath offer the UK an estimated 70 billion tonnes of potential CO2 storage space – something a number of industrial clusters on the UK’s east coast are exploring as part of their plans to decarbonise.

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

Drax is already running a pilot BECCS project at its power station in North Yorkshire. As part of the Zero Carbon Humber partnership and wider East Coast Cluster, Drax is involved in the development of large scale carbon storage capabilities in the North Sea that can serve the Humber and Teesside industrial clusters. As Drax moves towards its goal of becoming carbon negative by 2030, transporting CO2 safely at scale is a key focus.

“Much of the research and engineering has already been done around the infrastructure side of the project,” explains Richard Gwilliam, Head of Cluster Development at Drax. “Transporting and storing CO2 captured by the BECCS projects is well understood thanks to extensive engineering investigations already completed both onshore and offshore in the Yorkshire region.”

This also includes research and development into pipes of different materials, carrying CO2 at different pressures and temperatures, as well as fracture and safety testing.

The potential for the UK to build on this foundation and progress towards net zero is considerable. However, for it to fully manifest it will need commitment at a national level to building the additional infrastructure required. The results of such a commitment could be far reaching.

In the Humber alone, 20% of economic value comes from energy and emissions-intensive industries, and as many as 360,000 jobs are supported by industries like refining, petrochemicals, manufacturing and power generation. Putting in place the technology and infrastructure to capture, transport and store emissions will protect those industries while helping the UK reach its climate goals.

It’s just a matter of putting the pipes in place.

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

Global collaboration
is key to tackling
the climate crisis

Will Gardiner, Chief Executive Officer, Drax Group

22 April 2021

Opinion

Leaders from 40 countries are meeting today, albeit virtually, as part of President Joe Biden’s Leaders’ Summit on Climate. The event provides an opportunity for world leaders to reaffirm global efforts in the fight against climate change, set a clear pathway to net zero emissions, while creating jobs and ensuring a just transition.

Since taking office President Biden has made bold climate commitments and brought the United States back into the Paris Agreement. Ahead of the two-day summit, he announced an ambitious 2030 emissions target and new Nationally Determined Contributions. The US joins other countries that have announced significant reduction goals. For example, the EU committed to reduce its emissions by at least 55%, also South Korea, Japan and China have all set net-zero targets by mid-century.

Here in the UK, Prime Minister Boris Johnson this week outlined new climate commitments that will be enshrined in law. The ambitious new targets will see carbon emissions cut by 78% by 2035, almost 15 years earlier than previously planned. If delivered, this commitment which is in-line with the recommendations of the Climate Change Committee’s sixth carbon budget will put the UK at the forefront of climate action, and for the first time the targets include international aviation and shipping.

What makes climate change so difficult to tackle is that it requires collaboration from many different parties on a global scale never seen before. As a UK-North American sustainable energy company, with communities on both sides of the Atlantic, at Drax we are keenly aware of the need for thinking that transcends borders, creating a global opportunity for businesses and governments to work together towards a shared climate goal. That’s why we joined other businesses and investors in an open letter supporting the US government’s ambitious climate actions.

Collaboration between countries and industries

It’s widely recognised that negative emissions technologies will be key to global efforts to combat climate change.

At Drax we’re pioneering the negative emissions technology bioenergy with carbon capture and storage (BECCS) at our power station in North Yorkshire, which when up and running in 2027 will capture millions of tonnes of carbon dioxide (CO2) per year, sending it for secure storage, permanently locking it away deep under the North Sea.

Experts on both sides of the Atlantic consider BECCS essential for reaching net zero. The UK’s Climate Change Committee says it will play a major role in removing CO2 emissions that will remain in the UK economy after 2050 from industries such as aviation and agriculture that will be difficult to fully decarbonise. Meanwhile, a report published last year by New York’s Columbia University revealed that rapid development of BECCS is needed within the next 10 years in order to curb climate change and a recent report from Baringa, commissioned by Drax, showed it will be a lot more expensive for the UK to reach its legally binding fifth carbon budget between 2028 and 2031 without BECCS.

A shared economic opportunity

Globally as many as 65 million well-paid jobs could be created through investment in clean energy systems. In the UK, BECCS and negative emissions are not just essential in preventing the impact of climate change but will also be a key component of a post-Covid economy.

Government and private investments in clean energy technologies can create thousands of well-paid jobs, new careers, education opportunities and upskill workforces. Developing BECCS at Drax Power Station, for example, would support around 17,000 jobs during the peak of construction in 2028, including roles in construction, local supply chains and the wider economy. It would also act as an anchor project for the Zero Carbon Humber initiative, which aims to create the world’s first net zero industrial cluster. Developing a carbon capture, usage, and storage (CCUS) and hydrogen industrial cluster could spearhead the creation and support of tens of thousands of jobs across the Humber region and more than 200,000 around the UK in 2039.

Under the Humber Bridge

Additional jobs would be supported and created throughout our international supply chain. This includes the rail, shipping and forestry industries that are integral to rural communities in the US South and Western Canada.

A global company

As a British-North American company, Drax embodies the positive impact that clean energy investments have. We directly employ 3,400 people in the US, Canada, and the UK, and indirectly support thousands of families through our supply chains on both sides of the Atlantic. Drax is strongly committed to supporting the communities where we operate by investing in local initiatives to support the environment, jobs, education, and skills.

From the working forests of the US South and Western Canada to the Yorkshire and Humber region, and Scotland, we have a world-leading ambition to be carbon negative by 2030. At Drax, we believe the challenge of climate change is an opportunity to improve the environment we live in. We have reduced our greenhouse gas emissions by over 80% and transformed into Europe’s largest decarbonisation project. Drax Power Station is the most advanced BECCS project in the world and we stand ready to invest in this cutting-edge carbon capture and removal technology. We can then share our expertise with the rest of the world – a world where major economies are committing to a net zero future and benefiting from a green economic recovery.

If we are to reach the targets set in Paris, global leaders must lock in this opportunity and make this the decade of delivery.

The world’s leading sustainable biomass generation and supply business

Will Gardiner, Chief Executive Officer, Drax Group

13 April 2021

Opinion

Today we completed a transformational deal – our acquisition of Canadian biomass pellet producer Pinnacle Renewable Energy.

I’m very excited about this important acquisition and welcoming our new colleagues to the Drax family – together we will build on what we have already achieved, having become the biggest decarbonisation project in Europe and the UK’s largest single site renewable power generator as a result of us using sustainable biomass instead of coal.

The deal positions Drax as the world’s leading sustainable biomass generation and supply business – making us a truly international business, trading biomass from North America to Europe and Asia. It also advances our strategy to increase our self supply, reduces our biomass production costs and creates a long-term future for sustainable biomass – a renewable energy source that the UN’s IPCC says will be needed to achieve global climate targets.

It’s also an important milestone in Drax’s ambition to become a carbon negative company by 2030 and play an important role in tackling the global climate crisis with our pioneering negative emissions technology BECCS.

That’s because increasing our annual production capacity of sustainable biomass while also reducing costs helps pave the way for our plans to use bioenergy with carbon capture and storage (BECCS) at Drax.

Negative emissions from BECCS are vital to address the global climate emergency while also providing the renewable electricity needed for a net zero economy, supporting jobs and clean growth in a post-Covid recovery.

Inside a Pinnacle pellet mill

Inside a Pinnacle pellet mill

We already know Pinnacle well – it is one of our key suppliers and the company is a natural fit with Drax.

Our new colleagues have a wealth of operational and commercial expertise so I’m looking forward to seeing what we can achieve together.

We will benefit from Pinnacle’s scale, operational efficiency and low-cost fibre sourcing, that includes a high proportion of sawmill residues. In 2019, Pinnacle’s production cost was 20% lower than Drax’s.

Completing this deal will increase our annual production capacity to 4.9 million tonnes of sustainable biomass pellets at 17 plants in locations across Western Canada and the US South – up from 1.6Mt now.

It also expands our access to three major North American fibre baskets and four export facilities, giving us a large and geographically diversified asset base, which enhances our sourcing flexibility and security of supply.

This positions us well to take advantage of the global growth opportunities for sustainable biomass. The market for biomass wood pellets for renewable generation in Europe and Asia is expected to grow in the current decade, principally driven by demand in Asia.

Biomass wood pellet storage dome, Drax Power Station

Biomass wood pellet storage dome, Drax Power Station

We believe that with increasingly ambitious global decarbonisation targets, the need for negative emissions and improved understanding of the role that sustainably sourced biomass can play, will result in continued robust demand.

Pinnacle is already a key supplier of wood pellets to other markets with C$6.7 billion of long-term contracts with high quality Asian and European customers, including Drax, and a significant volume contracted beyond 2027.

Drax aims to leverage Pinnacle’s trading capability across its expanded portfolio. We believe that the enlarged supply chain will provide greater opportunities to optimise the supply of biomass from its own assets and third-party suppliers.

The transport and shipping requirements of the enlarged company will provide further opportunities to optimise delivery logistics, helping to reduce distance, time, carbon footprint and cost.

Train transporting biomass wood pellets arriving at Drax Power Station

Importantly – there will also be opportunities to share best practice and drive sustainability standards higher across the group.

We recognise that the forest landscape in British Columbia and Alberta is different to the commercially managed forests in the south eastern US where we currently operate.

In line with our world leading responsible sourcing policy, Drax will work closely with environmental groups, Indigenous First Nation communities and other stakeholders and invest to deliver good environmental, social and climate outcomes in Pinnacle’s sourcing areas.

We are determined to create a long-term future for sustainable biomass and deliver BECCS –  the negative emissions technology that will be needed around the world to meet global climate targets. The acquisition of Pinnacle takes us a big step forward in achieving our goals.

Read press release: Drax completes acquisition of Pinnacle Renewable Energy Inc.

 

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 climate change?

21 August 2020

Sustainable business
Climate change

What is climate change?

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

What causes climate change?

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

Key climate crisis facts

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

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

How do humans contribute to climate change?  

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

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

Why are rising temperatures harmful to the planet?

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

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

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

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

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

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

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Plant more forests and better manage them

22 June 2020

Sustainable bioenergy
Working forests in the US South

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

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

Different age class forest stands in Louisiana

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

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

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

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

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

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

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

What happens when you close the gate

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

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

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

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

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

Pine trees in Mississippi working forest

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

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

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

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

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

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

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

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

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

Wildfires in the US

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

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

Forest fire in California

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

How should we manage the forest

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

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

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

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

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

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

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