BECCS deployment

The risks of policies forging ahead of the evidence

Research paper Published 1 October 2021 ISBN: 978 1 78413 495 2

Bioenergy facility for power generation, Scotland

Dr Daniel Quiggin

Senior Research Fellow, Environment and Society Centre

Due to the slow pace of decarbonization, climate models are increasingly reliant on carbon removal technologies – such as bioenergy with carbon capture and storage (BECCS) – to limit global warming and avoid catastrophe. BECCS has the potential to generate power and remove CO₂ from the atmosphere, but the technology is largely unproven at commercial scale and there are significant risks, including impacts on land use and food production as well as additional emissions along wood pellet supply chains.

While BECCS may have a valuable role in minimizing the impacts of climate change, real world applications suggest that its carbon capture efficiency may be less than the 90 per cent capture rate planned for in climate models. There is a clear need for policy action that not only minimizes the inherent risks of BECCS under delivering on negative emissions, especially as the technology is used more widely, but also reduces our reliance on BECCS to mitigate climate change.

04 Feedstock choice: Carbon efficiency and carbon debt

The risks of carbon debt remain a concern due to potential scaling pressures on wood pellet supply chains. In the UK, wheat straw may provide the optimal carbon efficiency as a feedstock.

There has been much debate over supply chain emissions of wood pellets, both in the context of BECCS and traditional biomass power plants.49 The Drax power plant in the UK is the largest importer of wood pellets in Europe. Drax has put significant efforts into trying to ensure its supply chain is decarbonized and attempting to ensure that the sourcing of its wood pellets is sustainable. The subsidies it receives from the UK government are dependent on adherence to sustainability criteria, which include requirements for legal and sustainable sourcing (including provisions for minimizing harm to ecosystems as well as for maintaining the productivity of the forest and ecosystem biodiversity health and vitality) and targets for GHG savings per unit of electricity (though this only covers emissions from the supply chain of the feedstock – harvesting, processing and transport; emissions from combustion are excluded on the assumption these are recaptured by forest growth).

Under GHG reporting requirements, biomass is considered carbon neutral at the point of combustion. However, the reality of supply chain emissions and potential carbon debt could result in wood-pellet-based BECCS failing to deliver the negative emissions that are technically possible. Carbon debt is the amount of carbon stored within a tree, plus the emissions from the supply chain of the feedstock, that must be replaced by the next generation of growth before the emissions captured and stored by BECCS can be considered negative. The following sections discuss carbon debt in the context of current sourcing of wood pellets from forests in the southeast of the US – where Drax sources more than 60 per cent of its wood pellets – and how the pressures on supply chains as BECCS scales up in the future could cause carbon debt to become a significant issue.

4.1 Carbon efficiency of a UK Drax-like wood pellet supply chain

Before turning to the carbon debt of wood pellets, it is worth examining the potential carbon efficiency of a future UK BECCS power plant on the basis of Drax’s supply chain emissions, as Drax itself reported in 2021.50 Figure 5 shows the supply chain emissions, converted into carbon efficiency, factoring in a 90 per cent capture rate and losses due to the energy needed to pipe the CO₂ to the storage site. Carbon efficiency can be thought of as the proportion of carbon input to the whole BECCS system that is geologically stored. Or alternatively, as the proportion of carbon input (i.e. CO₂ sequestered by biomass during growth) to the whole BECCS system that leads to net removal when accounting for life cycle emissions of the biomass feedstock. Carbon efficiency is synonymous with carbon negativity: a carbon efficiency of 0 per cent would result in BECCS being carbon neutral, rather than net negative.51

As can be seen from Figure 5, the supply chain emissions that Drax reports,52 combined with assumptions as to downstream CO₂ losses from the uncaptured emissions, as well as those from transport and storage would see around 24 per cent of the aggregate embodied CO₂ emitted to the atmosphere, and around 76 per cent geologically stored. This of course assumes trees are planted to replace those combusted in the BECCS facility, and ignores the time needed for the growing trees to recapture the carbon emitted on combustion (see the discussion on carbon payback periods below).

In most policy discussions, the capture rate is often referred to as the principal loss of CO₂, and the wood pellets are assumed to be carbon neutral. But as can be seen from Figure 5, emissions from the pelleting, transportation, and piping of the CO₂ to storage sites are not insignificant. Furthermore, it should be noted that Figure 5 does not touch upon or include any arguments surrounding carbon debt and assumes that an equivalent mass of trees is grown to replace that comprising the wood pellets. As such, Figure 5 is free of those debates and is therefore a representation of the carbon efficiency at any given moment of BECCS operation.

Figure 5. Carbon efficiency of a future wood pellet BECCS-to-power plant, based on Drax’s current supply chain, assuming a 90 per cent capture rate and 5 per cent transport and storage losses (T&S)

— Note: Values from Drax’s annual report converted on the basis of the embodied CO₂ of the wood pellets (1.8 kg CO₂/kg dry matter (DM), also calculated from Drax’s annual report).

4.2 The risks of wood pellet carbon debt as BECCS is scaled

As the number of net zero pledges by countries indicates, along with the forecasts of the IEA and IAM pathways of the IPCC SR1.5 report,53 the future scale up of BECCS could be enormous. As Table 1 indicates, to scale BECCS-to-power solely combusting wood pellets to meet the UK CCC 2050 target of 51 MtCO₂/yr would require the combustion of more than four times that currently burnt at Drax, and 126 times greater to meet the ‘middle-of-the-road’ IPCC 1.5°C pathway, also by 2050. Such a significant global scaling of wood pellet demand risks putting significant pressures on the global supply chains. Clearly alternative feedstock choices are available, other than woody biomass. However, given that the leading BECCS developer uses 97 per cent woody biomass (3 per cent agricultural residues54) and the global supply of pellets comprised of other feedstocks remains marginal, the scaling comparison of Table 1 is an indicator of the upper limit to wood pellet scaling over the next 30 years. It is also interesting to note that the UK CCC BECCS removal target of 51 MtCO₂/yr would require 119 per cent of the 26 Mt of wood pellets consumed across the EU27 + UK, which in turn represents 50 per cent of global consumption.55

Table 1. Scaling up BECCS-to-power solely combusting wood pellets to the UK CCC target and global IPCC IAM indications

	EU27 + UK (2018)	Drax (2020)	UK CCC Target* (2050)	Global IPCC** 1.5°C (2050)
Wood pellets burnt/required (Mt)	26	7	31	926
Embodied CO₂ (MtCO₂)56	47	13	57	1667
CO₂ capture potential (90% capture rate) (MtCO₂)	42	12
CO₂ capture target (90% capture rate) (MtCO₂)			51	1500

*Net zero, further ambition scenario;57 **‘middle-of-the-road’ IPCC 1.5°C compliant pathway.58

Source: Compiled by the author.

The initial combustion of biomass, along with the associated life cycle emissions of the biomass feedstock, create what is termed a ‘carbon debt’. Over time, regrowth of the harvested forest removes this carbon from the atmosphere, reducing the carbon debt. The period until carbon parity is achieved is usually termed the ‘carbon payback period’.

Calculating carbon payback periods is complex, because they depend not only on the type of feedstock used, but on the counterfactual – what would have happened to the feedstock if it had not been used for energy. The shortest carbon payback periods derive from the use of residues and wastes from forest industries that imply no additional harvesting and would otherwise be burnt as waste or left to decay, releasing carbon to the atmosphere in any case. The longest carbon payback periods derive from increasing harvest volumes in managed forests, harvesting natural forests or converting them into plantations, or displacing wood from other uses. Where whole trees are harvested and used for energy, not only is the stored carbon in the tree released into the atmosphere immediately, but the future carbon sequestration capacity of the tree is lost, and it takes time for the residual trees or new trees to compensate. Plantation forests have higher growth rates than natural forests and are typically harvested at a relatively young age, while naturally regenerated forests tend to be older and have larger trees when harvested; therefore, more stored carbon is lost when natural forests are harvested.

On the other hand, in the absence of forest management, the rate of net carbon absorption by most forests falls as the incidence of dead and diseased trees increases, and over time the forest may also become more vulnerable to wildfire or other disturbances. There can, therefore, be benefits over the long term from some level of management, and in the absence of demand for wood for energy or other products, many forests may not be managed in a manner that can increase forest carbon stocks.59 However, this assumes that forest management for conservation is not subsidized in the way that biomass for energy currently is.

It is often claimed that using thinnings of trees from forest management practices – which account for about 30 per cent of Drax’s feedstock – results in shorter carbon payback periods because they promote tree growth and allow higher stocking of trees.60 It should, however, be noted that the evidence on thinning practices indicates forest carbon stocks are either redistributed (to the remaining trees),61 or decline.62

While using wastes and residues as feedstock minimizes the carbon payback period, the volumes available are limited. Thus, as BECCS is developed at scale, there is a risk of using feedstocks with longer and longer carbon payback periods. Particular attention needs to be paid to the carbon payback period if roundwood from mature trees63 enters the supply chain. This is principally because mature trees take many years to grow, and support greater soil carbon, meaning any next generation tree replacement (plantation saplings) would be subject to a significant carbon payback period. The carbon payback period of a mature tree is likely to be at the upper end of the range of 44–104 years (calculated for a clearcut forest),64 but could be longer,65 meaning geologically stored CO₂ from mature trees should not be considered carbon negative until the next generation of trees has grown for this period of time.

Figure 6 illustrates the risks of carbon debt, as wood pellet supply is scaled to service the future global demand from BECCS. It should be noted that the diagram is not applicable to a supply chain of wood pellets derived from plantations grown on marginal or degraded land. As can be seen, the energy requirement to dry high-moisture-content woody biomass, and conversion of mature forests to plantations represent the major potential supply chain emissions. The sustainability criteria in place currently in the UK and EU do not place limits on feedstocks by category, though in July 2021 the European Commission published proposals for modifications to the EU’s sustainability criteria, which would end incentives for using saw or veneer logs, stumps and roots, and also prohibit sourcing from primary forests. Transparent monitoring and enforcement of sustainability criteria is often challenging. This is illustrated by investigating the sourcing of wood pellets from the US southeast.

As noted above, Drax complies with the UK’s sustainability criteria for solid biomass. The company’s 2020 annual report indicates that 36 per cent of its wood pellets are derived from low-grade roundwood. While this may be parts of trees not utilized for wood products, there is a risk that it can contain whole trees, even mature trees. Of the total supply, 63 per cent is sourced from the US southeast, of which 38 per cent is low-grade roundwood. Although Drax diligently reports the categories of feedstock sources used within its own mills, only 20 per cent is currently sourced from pellet mills it directly owns.66 To ensure wood pellets sourced from suppliers are compliant with regulations, supply chain emissions are minimized and forests sustainably managed, Drax requires suppliers to be certified under the Sustainable Biomass Program (SBP).67 However, concerns surround potential flaws in SBP standards,68 with critics concerned SBP certification leaves open loopholes that could undermine the sustainability of wood pellets.

Reporting by saw and pellet mills in the US as to their forest extraction practices is not mandatory. The US Department of Agriculture (USDA) Forest Service Forest Inventory and Analysis (FIA) programme utilizes sampling techniques to estimate the timber product output (TPO). The TPO data provides a means to estimate the feedstock sources used in the mills, as well as the health of forest and carbon stocks.69 At the forest level, rather than the mill level, the vast areas of the forests and large number of plots necessitates the sampling approach adopted by the FIA. In the state of Mississippi, in 2019, there were nearly 4,000 plots that were forested, with around 10–20 per cent of those plots visited and measured by field crews each year.70

Utilizing the FIA data, a 2020 study investigated the impacts of recent wood pellet production expansion in the US. While the study found ‘largely positive trends in timberland conditions… potentially negative trends suggests that continued monitoring of localized impacts of wood pellet mill operations is important’.71 When looking at the specifics of pellet mill procurement areas in close proximity (within 122 km) to exporting ports in the US coastal southeast, the study found around 400 million fewer live trees compared to other eastern US procurement areas, equivalent to 554 fewer live trees per hectare. And importantly the study states that, ‘in the US coastal southeast there were fewer live and growing-stock trees and less carbon in soils with every year of milling operation than in the rest of the eastern US’. It should be noted that this is only one study. However, very few studies have recently investigated the specifics of wood pellet demand pressures on forest management and sourcing practices in this region. Given wood pellet sourcing in the US southeast has rapidly expanded in recent years, and the potential drawbacks of mill reporting and SBP certification, this study is an early indicator of the risks that increased demand pressure can place on supply chains. If these trends continue the risks of carbon debt associated with wood pellets could correspondingly increase. Considering the 44–104-year carbon payback periods, and that carbon budgets to limit global warming to 2°C run till the end of the century, pressure on wood pellet supply chains should be minimized to mitigate carbon debt risks.

Figure 6. The risks of carbon debt as wood pellet supply chains scale with increased global BECCS demand

— Note: Applicable to mature forests, not for instance SRC willow. Not applicable to converting marginal or degraded land.

For an importing country, such as the UK, this future risk could be mitigated by sourcing woody biomass domestically as tight regulations are more easily enforced within a domestic supply chain, rather than import compliance being reliant on voluntary reporting, sampling or inadequate certification schemes.

To mitigate the risks of carbon debt undermining the carbon negativity of BECCS as wood pellet supply chains are scaled up, BECCS feedstocks should be diversified to ease future demand pressures. Furthermore, it is impossible for biomass pellets derived from other bioenergy feedstocks, such as grasses (miscanthus and switchgrass), to be whole trees in disguise. Or in other words, the issues of transparent reporting to ensure the minimization of carbon payback periods from the use of forest biomass all but vanish. That said, other feedstocks can exhibit a carbon debt if significant land-use change (LUC) is required to cultivate the first generation of that feedstock. For instance, if forests were clear felled to grow miscanthus, or indeed grassland or cropland converted. Or indeed if indirect LUC (ILUC) occurs due to displacing the original agriculture. The avoidance of carbon debt and associate payback periods is, therefore, contingent on ensuring that the conversion of land for the growth of bioenergy feedstocks is constrained to marginal and degraded land.

4.3 Carbon efficiency of the remaining feedstock choices

As was highlighted in section 4.1, paying due attention to feedstock supply chain emissions is integral in determining the carbon efficiency of BECCS. Figure 7 illustrates the carbon efficiency of four biomass feedstocks domestically grown in the UK (for a comparison see Figure A1 in annex for US imported values). The range of values in each Sankey diagram represents the upper to lower range of carbon efficiencies for different BECCS value chain configurations in the Modelling and Optimisation of Negative Emissions Technologies (MONET) framework.72 The upper end of the range represents a future scenario of decarbonized supply chains, with feedstocks grown on marginal and degraded land (hence near-zero LUC and ILUC emissions), while the lower end is based on current energy system carbon intensities, with high LUC and ILUC emissions factored in based on converting grassland, both modelled under the MONET framework. It should be noted that wheat straw is always assumed to have no associated indirect or direct land-use change emissions, as it is an agricultural residue. Furthermore, MONET does not consider other agricultural residues, waste wood, forestry wood, and municipal solid wastes. MONET also makes conservative assumptions regarding supply chain emissions, biomass losses along the value chain, as well as the emissions associated with piping the CO₂ to the geological storage site. As such, real world carbon efficiencies may demonstrate higher values than those provided in Figure 7. However, the range of MONET values are important indicators, given the academic literature is extremely limited in assessing the potential carbon efficiency of BECCS, based on a range of feedstocks and differences between feedstock growth regions.

As can be seen from Figure 7c, wheat straw may provide a significantly superior carbon efficiency: 74–72 per cent of the CO₂ is geologically stored, and 26–28 per cent emitted to the atmosphere. Miscanthus is the second-best performing feedstock, with 74–33 per cent geologically stored. Switchgrass and SRC willow are significantly lower at 71 per cent to 8 per cent and 72 per cent to 3 per cent, respectively. It should be noted that for both these feedstocks, current supply chain emissions (i.e. carbon intensity of energy systems) and conversion of grassland (high LUC and ILUC emissions) result in only marginal net negativity.

Wheat straw demonstrates a superior carbon efficiency due to marginal LUC and ILUC emissions, and a lowered drying requirement during the pelleting process. For the upper range scenario – where all feedstocks are assumed to be grown on marginal and degraded land and supply chain emissions are heavily decarbonized – the carbon efficiency gap between wheat straw and the other feedstocks significantly narrows. Under this optimistic scenario wheat straw outperforms miscanthus by 0.6 per cent in terms of carbon efficiency, 3 per cent compared to switchgrass and by 2 per cent compared to SRC willow. It should be noted that other agricultural residues could be used, and that these alternatives have not been assessed.

The upper range scenario carbon efficiencies of miscanthus, switchgrass and wheat straw decline when shifting to importing the feedstock pellets from the US (Figure A1 in annex), all by around 11 per cent, and SRC willow by around 12 per cent.

Given the principal objective of BECCS is to remove CO₂ from the atmosphere and permanently store it in geological formations, feedstock choice should ensure the greatest carbon efficiency and hence net negativity.

Given the principal objective of BECCS is to remove CO₂ from the atmosphere and permanently store it in geological formations, feedstock choice should ensure the greatest carbon efficiency and hence net negativity. While all the feedstocks illustrated in Figure 7 (and Figure A1) remove CO₂ from the atmosphere, the greater the carbon efficiency (proportion of CO₂ geologically stored) the less feedstock required to achieve a given removal target. If less feedstock is required, less land is needed, which in turn minimizes the risk of land tensions with food production. Another way to view this is that for a finite amount of land, more CO₂ would be geologically stored compared to atmospheric emissions if the feedstock with the greatest carbon efficiency and net negativity were chosen. On this basis wheat straw may offer the optimal choice. Furthermore, minimal LUC is associated with wheat straw given it is a waste product to wheat production, which is already ubiquitous across many countries’ agricultural sectors. Although the upper range of carbon efficiencies in Figure 7 are representative of growing feedstocks on marginal and degraded land, ensuring conversion of land does not result in LUC and ILUC emissions is not a risk if wheat straw pellets were utilized.

Figure 7. Carbon efficiency of UK BECCS based on (a) miscanthus, (b) switchgrass, (c) wheat straw and (d) short rotation crop (SRC) willow, grown domestically in the UK

— Note: The range of values is representative of decarbonized future supply chains and minimal LUC/ILUC (low carbon) and current supply chains (current energy systems) with high LUC/ILUC assuming grassland conversion to bioenergy (high carbon). For US imported equivalent diagrams see Figure A1 in the annex.

Brack, D., Hewitt, J. and Marchand, T. M. (2018), Woody Biomass for Power and Heat: Demand and Supply in Selected EU Member States, London: Chatham House, https://www.chathamhouse.org/2018/06/woody-biomass-power-and-heat.

Drax (2021), Drax Group plc Annual report and accounts 2020.

Fajardy, M. and Mac Dowell, N. (2017), ‘Can BECCS deliver sustainable and resource efficient negative emissions?’, Energy and Environmental Science, 10(6), doi:10.1039/c7ee00465f.

Drax (2021), Drax Group plc Annual report and accounts 2020.

IPCC (2018), Global Warming of 1.5°C.

Drax (2021), ‘Sourcing Sustainable Biomass’, https://www.drax.com/sustainability/sustainable-bioenergy/sourcing-sustainable-biomass.

Bioenergy Europe (2019), Report Pellet, Statistical Report 2019, https://epc.bioenergyeurope.org/wp-content/uploads/2020/02/SR19_Pellet_final-web-1.pdf.

These figures represent the emissions released on combustion. A more comprehensive analysis, including emissions from energy use in the supply chain and forgone removals of carbon dioxide from the atmosphere due to the harvesting of live trees and emissions from the decay of roots and unused logging residues left in the forest after harvest, is discussed in Birdsey, R., Brack, D. and Walker, W. (forthcoming 2021), Greenhouse gas emissions from burning US-sourced woody biomass in the EU and UK, Research Paper, London: Royal Institute of International Affairs.

CCC (2019), Net Zero: The UK’s contribution to stopping global warming.

IPCC (2018), Global Warming of 1.5°C.

Dale, V. H. et al. (2017), ‘Status and prospects for renewable energy using wood pellets from the southeastern United States’, GCB Bioenergy, 9(8), doi:10.1111/gcbb.12445.

Garcia-Gonzalo, J., Peltola, H., Briceño-elizondo, E. and Kellomäki, S. (2007), ‘Changed thinning regimes may increase carbon stock under climate change: A case study from a Finnish boreal forest’, Climatic Change, 81(3): pp. 421–454, doi:10.1007/S10584-006-9149-8.

Schaedel, M. S., Larson, A. J., Belote, T., Goodburn, J. M., Page-Dumroese, D. S. and Affleck, D. L. R. (2017), ‘Early forest thinning changes aboveground carbon distribution among pools, but not total amount’, Forest Ecology and Management, 389: pp. 187–198, doi:10.1016/j.foreco.2016.12.018; Zhang, X., Guan, D., Li, W., Sun, D., Jin, C., Yuan, F., Wang, A. and Wu, J. (2018), ‘The effects of forest thinning on soil carbon stocks and dynamics: A meta-analysis’, Forest Ecology and Management, 429: pp. 36–43, doi:10.1016/J.FORECO.2018.06.027.

Lin, J-C., Chiu, C-H., Lin, Y-J. and Liu, W-Y. (2018), ‘Thinning Effects on Biomass and Carbon Stock for Young Taiwania Plantations’, Scientific Reports, 8(1), doi:10.1038/s41598-018-21510-x; Bravo-Oviedo, A., Ruiz-Peinado, R., Modrego, P., Montero, G. and Ponce, A. R. (2015), ‘Forest thinning impact on carbon stock and soil condition in Southern European populations of P. sylvestris L.’, Forest Ecology and Management, 357: pp. 259–267, doi:10.1016/J.FORECO.2015.08.005.

Mature tree: CO₂ absorbed through photosynthesis near equals the CO₂ output via respiration, hence additional sequestration is significantly lower than that of a fast-growing immature tree.

Rolls, W. and Forster, P. M. (2020), ‘Quantifying forest growth uncertainty on carbon payback times in a simple biomass carbon model’, Environmental Research Communications, 2(4), doi:10.1088/2515-7620/ab7ff3; Sterman, J. D., Siegel, L. and Rooney-Varga, J. N. (2018), ‘Does replacing coal with wood lower CO₂ emissions? Dynamic lifecycle analysis of wood bioenergy’, Environmental Research Letters, 13(1), doi:10.1088/1748-9326/aaa512.

Holtsmark, B. (2010), Use of wood fuels from boreal forests will create a biofuel carbon debt with long payback time, Discussion Papers No. 637, Oslo: Statistics Norway, https://www.ssb.no/a/publikasjoner/pdf/DP/dp637.pdf.

Drax (2021), Drax Group plc Annual report and accounts 2020.

Drax (2021), ‘Sourcing Sustainable Biomass’.

NRDC (2017), The Sustainable Biomass Program: smokescreen for forest destruction and corporate non-accountability, https://www.nrdc.org/resources/sustainable-biomass-program-smokescreen-forest-destruction-and-corporate-non.

Young, J. B. and Edgar, C. B. (2019), Advancing Estimation of Timber Products Output in the Lake States Region of the Northern United States, Minnesota: University of Minnesota, https://conservancy.umn.edu/handle/11299/215045.

USDA (2020), ‘Forests of Mississippi, 2019’, https://public.tableau.com/views/FIA_OneClick_V1_2/Factsheet ?%3AshowVizHome=no.

Aguilar, F. X., Mirzaee, A., McGarvey, R. G., Shifley, S. R. and Burtraw, D. (2020), ‘Expansion of US wood pellet industry points to positive trends but the need for continued monitoring’, Scientific Reports, 10(1), doi:10.1038/s41598-020-75403-z.

Fajardy and Mac Dowell (2018), ‘The energy return on investment of BECCS: is BECCS a threat to energy security?’; Fajardy and Mac Dowell (2017), ‘Can BECCS deliver sustainable and resource efficient negative emissions?’; Farjardy, M. and Mac Dowell, N. (2020), ‘Recognizing the Value of Collaboration in Delivering Carbon Dioxide Removal’, One Earth, 3(2): pp. 214–225, doi:10.1016/j.oneear.2020.07.014; Fajardy, M., Chiquier, S. and Mac Dowell, N. (2018), ‘Investigating the BECCS resource nexus: Delivering sustainable negative emissions’, Energy and Environmental Science, 11(12), doi:10.1039/c8ee01676c; Fajardy, M. (2020), Developing a framework for the optimal deployment of negative emissions technologies, London: Imperial College London, https://spiral.imperial.ac.uk/handle/10044/1/80691.

Fajardy and Mac Dowell (2018), ‘The energy return on investment of BECCS: is BECCS a threat to energy security?’; Fajardy and Mac Dowell (2017), ‘Can BECCS deliver sustainable and resource efficient negative emissions?’; Farjardy and Mac Dowell (2020), ‘Recognizing the Value of Collaboration in Delivering Carbon Dioxide Removal’; Fajardy, M., Chiquier, S. and Mac Dowell, N. (2018), ‘Investigating the BECCS resource nexus: Delivering sustainable negative emissions’; Fajardy (2020), Developing a framework for the optimal deployment of negative emissions technologies.

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BECCS deployment

Dr Daniel Quiggin

04 Feedstock choice: Carbon efficiency and carbon debt

4.1 Carbon efficiency of a UK Drax-like wood pellet supply chain

Figure 5. Carbon efficiency of a future wood pellet BECCS-to-power plant, based on Drax’s current supply chain, assuming a 90 per cent capture rate and 5 per cent transport and storage losses (T&S)

4.2 The risks of wood pellet carbon debt as BECCS is scaled

Table 1. Scaling up BECCS-to-power solely combusting wood pellets to the UK CCC target and global IPCC IAM indications

Figure 6. The risks of carbon debt as wood pellet supply chains scale with increased global BECCS demand

4.3 Carbon efficiency of the remaining feedstock choices

Figure 7. Carbon efficiency of UK BECCS based on (a) miscanthus, (b) switchgrass, (c) wheat straw and (d) short rotation crop (SRC) willow, grown domestically in the UK