“Sustainable biomass has played a central role in taking the UK off coal, provided an important back-up for wind power and is critical to achieving net zero by 2050 through Bioenergy with Carbon Capture and Storage (BECCS). The UK has world-leading sustainability criteria which prevent the supply of biomass for energy generation from areas where deforestation or land use change has occurred.

“In this case, a section of forest was legally harvested to supply wood for industries including construction, joinery and bioenergy. The harvest took place in line with Natura 2000 agreements and under strict controls and regulations and there’s nothing to suggest that this harvest was inappropriate. Moreover, tree cover in both Estonia and Latvia has increased in recent years, underlining the sustainable nature of the forestry operations there.

“Furthermore, this report incorrectly cites bioenergy as the main driver for harvesting in the Baltic region. This ignores basic forestry economics that clearly demonstrate that harvests are driven by the significantly more valuable timber used in housebuilding and furniture than the cheaper forestry residues that are used for bioenergy. The article also ignores important relevant context, for example, that economic recovery since the financial crash has led to a recovery of forestry operations to supply wood for housebuilding, among other things.

Updated: Jan 14

A recent report, covered by the Guardian, claims to investigate biomass supply chains from the Baltic region to the UK, among other countries. We’ve looked at some of the report’s key claims and corrected the misleading portrayal of the biomass industry and the sustainable forestry sector.

1) Emissions from biomass vs fossil fuels

First of all, the report repeats the claim made frequently by dedicated anti-biomass organisations that emissions from electricity generation from bioenergy are substantially (in the realm of 50%) higher than emissions for coal. This is simply not true. This claim is based solely on stack emissions, though even here the difference is much smaller. Biomass releases slightly more CO2e at the point of combustion than coal, but efficient plant, for example at Drax Power Station, reduce this to about 2%.

Crucially, this cherry-picking ignores the fundamental difference between fossil fuels, which introduce carbon into the atmosphere that was previously locked away for millennia, and biogenic carbon. Biogenic carbon is constantly exchanging between organic material and the atmosphere through organic growth and decay. Bioenergy makes use of this cycle. UK sustainability regulations ensure that the use of biomass for energy results in significant carbon savings compared to fossil fuels across the whole lifecycle, as do the updated EU regulations in RED II.

To take the UK (a leading example of sustainable biomass use), public support for biomass has allowed rapid decarbonisation of electricity grids. These subsidies have allowed us to reduce our dependence on coal, maintain flexibility on the grid and support thriving forests. The UK has reduced electricity emissions by 71.7% since 1990, with biomass playing a significant role in allowing coal to be phased out and supporting the development of intermittent renewables, such as wind and solar energy.

2) The “carbon debt” fallacy

Secondly, the report claims that harvesting wood creates a carbon debt. The following quote is taken from the report and is indicative of the misunderstanding of how sustainable forest management works: “If we count a period of, say, 40 years, in which the new trees have canceled the carbon debt, then yes that biomass can be seen as carbon neutral,” he says. "But if we consider a very short period of time, it is likely that the carbon debt will not be canceled.”

Yes, if one considers only an individual tree, or even only a specific stand of trees, then this may hold some weight. Forest management takes place at the landscape scale, however. Indeed, consideration of carbon sequestration and emissions in forests only makes sense if it is done at this landscape scale. Sustainable forest management is a matter of balancing growth and harvesting rates so that growth exceeds harvesting. That leads to year-on-year increases in the volume of growing trees, capturing more and more carbon each year. The report claims that small spruces will take decades to absorb the same amount as the felled tree, but this doesn’t address the big picture of growth across the forest.

A recent report from leading forestry consultancy Indufor concluded that Estonia’s forest area has increased to 52% of the total land in 2018 compared with 49% in 2010, and over the same period the total growing stock has increased by 52 million cubic metres with 40% of this growth in hardwood species.

3) Carbon accounting for biomass

The report refers to a “magic trick” of carbon accounting where emissions of biomass power are not counted at the power station, leading to the claim that the CO2 emissions have “effectively disappeared.” In fact, international carbon accounting standards, which include biomass power, do count the emissions of biomass power, they just do it under the AFOLU (i.e. forestry) sector rather than the energy sector. It reflects the fact that biogenic carbon is constantly being exchanged between the atmosphere and organic material. In a sustainably managed forest, ongoing growth balances out harvesting.

This is done for a number of reasons: a) to avoid emissions being counted twice, b) it’s simpler to track the real emissions accurately, and c) it allows for transporting biomass across borders, which happens a lot given the uneven spread of forest resources around the world (for example, the Southern USA’s forests cover an area three times the entire landmass of the UK).

This principle of carbon accounting (avoiding double counting) was re-examined and reaffirmed just last year by the UN’s Intergovernmental Panel on Climate Change (IPCC) and has been endorsed by the UK’s Climate Change Committee (CCC).

There’s more detailed information on the carbon accounting question here.

4) Biomass regulations – the importance of low-value wood

The report suggests that EU regulators were not following the science when they drew up the sustainability criteria for biomass and concentrates on the use of “whole trees” – a term that has no definition in the forestry industry. Leaving aside the carbon debt issue addressed above, it is important to understand that it is not the size of the tree which determines its value.

Bioenergy makes use of forest thinnings, which means small, diseased or misshapen trees that have low value for industries such as timber. They are removed to allow remaining trees more access to nutrients, meaning these trees will grow taller. This process maximises forest growth and also maximises carbon captured in structural timber or joinery wood. There is a clear, documented correlation between the productivity of forests and the volume of wood growing there. Reducing the ability to draw revenues from thinnings will reduce the ability of foresters to manage and invest in their forests. This white paper from September 2020 goes into more detail on the dangers of basing market interventions on arbitrary physical criteria.

The report claims that: “Since the revised Renewable Energy Directive and Estonian legislation does not ban the use of whole trees, Graanul Invest can harvest hectares of forests to turn into pellets in the name of sustainable management.” This simply does not make sense. It is the lowest quality wood that is used for bioenergy, as Graanul make clear here. The same is true for working forests all over the world – the raw material used for the production of wood pellets is always sourced from the bottom of the forest value chain.

Robert Matthews, a forestry expert for the UK government, was interviewed for the report, though all the information is not presented. His 15 recommendations from 2018 for sustainable biomass do allow for the use of “whole trees” as thinnings as part of sustainable forestry management. His recommendation (no. 12) on whole tree stems, runs as follows:

“Whole tree stems - Restrict supplies of forest bioenergy from whole tree stems to small/early thinnings with the aim of improving the quality of the remaining growing stock. Favour situations in which, otherwise, there would be limited incentives to thin and improve forest stands. Alternatively, favour supplies of wood biomass from small/early thinnings where a simply calculated but robust estimate of GHG emissions meets a defined minimum threshold.”

5) Certification

The report presents an overview of the various different certification regimes used for sustainable forest management, and heavily implies, through the presentation of a “flipside” for each one, that these schemes are inadequate. In many cases however, these schemes go beyond what is required by governments. The Sustainable Biomass Program (SBP) is singled out for criticism for using data from 2016 and saying that Estonian forest land is homogenous, as well as for its links to industry. This is a misleading representation of the situation.

SBP uses Regional Risk Assessments (RRAs) to understand the local geography and forest economy. This is updated every five years to take account of changing scientific evidence, market conditions and socio-political questions. The next review for Estonia is in 2021, so the authors of the report will get their wish as SBP will update the certification scheme’s baseline for Estonia. Latvia is due the following year.

SBP also has multi-stakeholder governance arrangements in place. Both civil society and commercial interests are represented at every level of governance, fostering dialogue, decision-making and implementation of solutions to common goals.

6) Estonian forestry regulations

The report concentrates on evidence of forestry operations in Haanja Nature Park, on land owned by Graanul Invest Group. Evidence is given through satellite images of clear-felling in Natura 2000 protected areas and used to paint a picture of deforestation and unsustainable practices. Important details have been left out, however.

The report’s portrayal ignores the reality of government-approved forest management in Estonia. The Nature Conservation Act in Estonia divides nationally protected areas into different protection zones: strict nature reserve, conservation zone and limited management zone. In the first two, human intervention is either completely prohibited or only allowed for non-economic purposes. The main purpose of the limited management zone, however, is to be a buffer zone between strictly protected areas and conventionally managed forests. In these limited management zones, forestry practices are permitted, though only with the express permission of the Estonian Environment Agency, and economic activities cannot interfere with conservation goals.

Clear-felling has been misrepresented in the report as an undesirable practice. In fact, it is the most widely used final forestry harvest system in the world. It is a normal part of forestry operations worldwide and is often the best way to ensure that the objectives of sustainable forest management are met. For its report on biomass in 2018, the CCC included an annex on Sustainable Forest Management. The first item in the list of sustainable forestry techniques? Clear-felling.

We also spoke with the Estonian Ministry of Environment, and they provided the following additional information.

  • “The carbon stock has increased [in Estonian forests] between 1990-2020 (by 15%) including the stock in above-ground and below-ground biomass, deadwood and soil, although the total felling volume has increased.”

  • “…during [the] last 5 years, the overall protected forest area has widened [by] more than 50,000 ha and more than 75,000 ha of different (mostly forest) habitats have been re-zoned from the limited management zone to strictly protected zone.”

To conclude…

The principles of forestry management are tried and tested and ensure that wood is directed to the most efficient end-use. This maximises carbon savings and revenues for foresters and incentivises the careful management of forests that will only grow more important as we fight against the dangers of climate change.

The biomass industry is playing a crucial role in reducing carbon dioxide emissions and supporting sustainable forest management. The regulations and carbon accounting principles for the use of biomass follow the science at every level, from national sustainability criteria, to the EU’s REDII, and the IPCC’s carbon accounting framework. These ensure that sustainable biomass provides tangible benefits for our climate and forests.

TL;DR: Sustainable biomass is supporting demonstrable year-on-year growth in forests. It also just helped the UK to go two months without coal for the first time since the industrial revolution. The campaign group Ember completely misread the science on forestry, called for carbon emissions to be double counted, then recommended a measure that would increase electricity bills.

The Ember campaign group (formerly Sandbag) has produced a paper that calls for an end to government support of biomass power.

It’s based on a misreading of the science, which leads its authors to make recommendations which would actually undermine the UK’s Net Zero strategy, which is embedded in a 2019 amendment to the Climate Change Act.

Not only that, but Ember notes the anti-biomass message this would send to other countries which are at earlier stages in their energy transitions away from fossil fuels such as coal. It would therefore undermine international efforts to fight the climate crisis.

We’ve taken some of the report’s key points and addressed the myths behind them.

The carbon debt fallacy

Sitting at the centre of this is the question of ‘carbon debt’. Without it, Ember’s argument is empty.

Put simply, critics of biomass agree that trees can recapture any carbon emitted by biomass power stations, but it takes decades for them to regrow, creating a ‘carbon debt’, which takes decades to pay back.

This is a misreading of how forestry systems work. It’s a question of scale. If we take one tree, cut it down and replant it, it will indeed take decades to regrow (about 35 years for faster softwoods, 80-120 years for hardwoods).

However, in a forest there are hundreds of millions of trees, and they’re at different stages of growth. This means that some will be mature, some have just been planted, some will be mid-way through their growth.

Therefore when the small portion that are harvested in a given year, about 2-3% of the forest in the Southern US region, there’s still 97% of the forest continuing to grow.

The graph below shows total forest inventory (scale on the left) compared to removals (scale on the right) in areas that supply Enviva, a major supplier of biomass to the UK.

The dotted black line is the removals for biomass – less than 0.1% of total inventory in a given year.

While all this is happening, total forest inventory is going up and up – carbon debt is not appearing.

Therefore the forest overall will almost immediately re-capture carbon emitted by the harvesting process. The other trees only need to grow by about 3-4% to balance out or even exceed harvesting, and this growth rate is ensured by active forest management, paid for by revenues from timber, joinery, pulp and paper and bioenergy markets. It wouldn’t happen at the same rate without active interventions.

It’s a matter of balancing growth and harvesting rates so that growth exceeds harvesting. That leads to year-on-year increases in the volume of growing trees, capturing more and more carbon each year.

This isn’t just a theory or a scientific model. It’s evident in the real-world data recorded over decades. The graph below is based on US Forest Service data and shows 70 years of increasing inventory (the amount of wood growing in the forest) in the Southern USA, all while supplying timber markets and, more recently, bioenergy markets too.

The point is, we don’t have to wait decades to recapture carbon – the forest as a whole is already doing it.

If the forest was in a state of ‘carbon debt’, then you’d see the lines going down (harvesting creating carbon debt), followed by slow recovery (repaying the debt). But in fact the lines are trending upwards.

Of course, there’s a big question here: wouldn’t it grow faster if we left it alone? The evidence suggests ‘no’.

When forests reach maturity, their overall growth tends to plateau. That’s because some trees are dying, others are growing, but overall mortality and growth level out. So the graph above would just show flat lines.

In fact, it’s possible for unmanaged forests to become net emitters, and this is increasingly a danger due to climate change.

Unmanaged forests are increasingly vulnerable to tree diseases (like Ash Die Back, which has been devastating to ash trees in the UK), infestations (like the boring beetles that have damaged vast numbers of trees in Canada) and forest fires (like the ones seen in Australia and California).

Markets for wood products help us to pay for investments in protective measures, such as managing the amount of dead material on forest floors, remove diseased trees and creating fire breaks or clearing deadwood that poses a fire risk.

On forest fires, it’s no surprise that California is actively looking at using bioenergy markets as one way to limit the risks, especially as the taxpayer-funded Forest Service experiences funding cuts.

In these markets, construction timber delivers the highest value, which also creates an incentive to grow big, tall trees and it leads to carbon being locked up in housing for decades – a win-win.

Other, lower quality materials, go to sectors including bioenergy, which tends to take the very lowest quality such as branches and misshapen or knotted wood.

The presence of these markets creates some very positive trends.

The graphs below show that, where wood product markets are active, we see higher growth rates, increases in forest land and increases in the amount of wood growing in a given area – all three mean more carbon is captured. And it’s true for softwoods and hardwoods.

Subsidies and value, or why biomass is worth public support

Knowing that we’re all concerned about money, Ember has focused its PR for the report on how much the UK has paid to biomass power stations, particularly Drax in North Yorkshire.

Yet they don’t show context, especially that these subsidies are to pay for 17% of UK renewable power – you’ll see subsidies paid to wind and solar, too, but that’s left out of Ember’s story.

Ember claims that you get more bang for your buck from wind, but this assumes that all electricity is the same. In reality, it’s not.

During the COVID-19 pandemic, we’ve seen a glimpse of the future, in which low-carbon energy sources are dominant.

This has created challenges for the grid, including ensuring that the system is stabilised and flexible enough to cope with ups and downs on an energy system which is rapidly evolving.

This requires particular technical services that biomass can provide, such as inertia, which basically smooths out the changes on the grid as energy sources ramp up and down and turn on or off, while demand is also fluctuating.

The costs of these services have been going up recently, partly because our system has low inertia, but biomass can offer it as a by-product of producing it low-carbon power.

Similarly, biomass offers useful things like long-term storage of energy (wood is basically a battery storing solar energy).

When the sun doesn’t shine or wind doesn’t blow, we need ready source of power. We don’t have battery technology that can provide this, so biomass is helping us to transition from fossil fuels to renewables.

These things are worth paying for, especially if we want a zero-emissions electricity grid by 2025, which is what National Grid is aiming for.

It’s also important to understand that biomass is laying the groundwork for negative emissions via healthy forest landscapes and Bioenergy with Carbon Capture and Storage (BECCS).

With BECCS, carbon is absorbed by trees growing, the trees are harvested and partly used to supply biomass power stations. Then the power station emissions are captured rather than released into the atmosphere. The carbon dioxide is then buried under ground or used in certain products.

Carbon Capture and Storage has been described by the UK’s Committee on Climate Change as “a necessity” for meeting Net Zero by 2050 and the CCC prescribed BECCS as a key component of large-scale zero-carbon industrial hubs.

BECCS is also a major player in two of the IPCC’s four pathways for avoiding catastrophic climate change.

Yet we won’t be able to deploy BECCS fast enough if biomass is undermined in the meantime. We need research and investment in technologies, supply chains and know-how if we’re going to implement BECCS, and that means supporting biomass now.

Drax in North Yorkshire is already conducting a pilot programme that capture one tonne of CO2 per day. We need to support this work, not hinder it, if we want to beat climate change.

‘Loopholes’, carbon neutrality and double accounting

Ember wrongly claims that there is a “loophole” in carbon accounting systems, allowing carbon emissions to be ignored.

The claim is based on the fact that biomass ‘stack emissions’ (a stack is the chimney of a power station, so ‘stack emissions’ refers to the power station’s emissions, as opposed to the supply chain’s) are counted as zero, because the biomass feedstock is regrown.

Ember sees this as accounting trickery, they think it ignores the forest’s carbon ‘account’. I.e. the forest could be losing (emitting) lots of carbon because of biomass power and it wouldn’t be noticed in the biomass supply chain.

In fact, international carbon accounting standards, which include biomass power, do count the emissions of biomass power, they just do it under the AFOLU (i.e. forestry) sector rather than the energy sector.

Amazingly, Ember leaves this out of their report – there’s no mention of the fact that biomass emissions are counted, but are counted at source, not at the stack.

They don’t seem to be aware of the UN’s carbon accounting of biomass at all, so it’s surprising to see them making recommendations about carbon accounting based on incomplete knowledge of the subject.

This accounting method exists because a) it’s simpler to track and b) it allows for transporting biomass across borders, which happens a lot given the uneven spread of forest resources around the world (for example, the Southern USA’s forests cover an area three times the entire landmass of the UK).

So, when wood pellets arrive at a UK power station, their emissions have already been recorded by the forestry sector wherever those trees grew.

Ember says that this ‘carbon neutrality’ approach is “outdated”. However, it was re-examined and reaffirmed just last year by the UN’s Intergovernmental Panel on Climate Change (IPCC) and has been endorsed by the UK’s Committee on Climate Change (CCC).

It’s worth noting that we do actually record the UK’s biomass emissions so that we have a more accurate idea of the energy sector, but not officially against international standards.

There’s more information on the carbon accounting question here.

If, as Ember suggests, we started to count the emissions at the power station as well, that would mean double-counting the same carbon emissions.

Firstly, that’s inaccurate and inaccuracy won’t help us in the fight against climate change.

Secondly, Ember says that these emissions must then be taxed, since the EU effectively taxes carbon emissions through its Emissions Trading System (ETS), which would raise electricity bills.

Such taxes inevitably end up on your electricity bill.

Effectively, Ember would like us all to pay higher bills in order to cover fictitious carbon emissions that they’ve dreamed up.


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