Title page
Contents
Summary 4
01. Introduction 6
1.1. Carbon budgets, net zero targets and the role of BECCS 8
1.2. The scale of BECCS being relied upon 10
1.3. BECCS in the integrated assessment models 10
1.4. The UK must be cognisant of offsetting risks 12
02. The system boundary is crucial 14
2.1. Capture rates are critical, but risk hiding the whole story 15
2.2. Biomass land requirements 16
03. Inefficient BECCS power plants - the optimal choice? 17
3.1. Maximum power generation or CO₂ capture 17
3.2. Inefficiency reduces societal good 20
04. Feedstock choice: Carbon efficiency and carbon debt 22
4.1. Carbon efficiency of a UK Drax-like wood pellet supply chain 23
4.2. The risks of wood pellet carbon debt as BECCS is scaled 24
4.3. Carbon efficiency of the remaining feedstock choices 29
05. The perfect (wheat straw) system? 32
5.1. Implications of a highly efficient BECCS fleet 33
5.2. Land required and supply chain emissions of wheat straw 34
06. Minimizing the risks 36
07. Conclusions and recommendations 39
Annex 42
About the author 43
Acknowledgments 43
Table 1. Scaling up BECCS-to-power solely combusting wood pellets to the UK CCC target and global IPCC IAM indications 25
Figure 1. IPCC illustrative pathways towards balanced carbon budgets, and the role of BECCS 9
Figure 2. Summary of IAM transparency ranking of BECCS modelling assumptions 12
Figure 3. The impacts of power efficiency of a future BECCS fleet on subsidies and aggregate CAPEX 19
Figure 4. Efficiency of BECCS assumed within IAMs 20
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... 24
Figure 6. The risks of carbon debt as wood pellet supply chains scale with increased global BECCS demand 28
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 31
Figure 8. Wheat straw based BECCS, under CCC net zero 'Further Ambition' scenario 34
Figure 9. Supply chain emissions under the CCC further ambition scenario, assuming domestic wheat straw supplies 100 per cent of the feedstock. requirement, all in units of CO₂ 35
Figure 10. Policy solutions for mitigating risks of BECCS 38
Boxes
Box 1. What is BECCS? 7
Annex Figures
Figure A.1. Carbon efficiency of UK BECCS based on (a) miscanthus, (b) switchgrass, (c) wheat straw and (d) short rotation crop (SRC) willow, grown in the US and imported to the UK 42