9.2.1 Main applications
Biomass use increases significantly in all scenarios (Figure 9.2), including REF (+77% by 2060) and CP30 (+104%), even though this use is more modest than in net-zero scenarios where it more than quadruples. At first, biofuel production increases in all scenarios and rapidly reaches a limit in NZ scenarios, where increases after 2030 are very limited. Instead, the two main uses of the additional biomass consumption are BECCS for hydrogen and electricity production, which constitute at least 73% of the total in 2060. In the case of electricity, this means that even if little biomass is used for generation in proportion to the total, its role is key in net-zero trajectories because of the significant negative emissions that are obtained from biomass-fired plants with CCS.
Figure 9.2 – Biomass consumption by application #
In fact, given that the burning of transformed biomass results in GHG emissions and that other alternative low-carbon energy sources are available, its cost-optimal use is for guaranteeing net-zero targets. In the short term, biomass can provide an alternative to other fuels in sectors, mainly transport, that are costly to decarbonize. However, beyond the short term, the use of biomass remains primarily associated with the possibility of attaining power and hydrogen production with negative emissions (BECCS) in specific applications particularly tailored for its use, and where other technologies remain too costly or do not yet exist.
9.2.2 Sensitivity analysis
The main constraint on the use of biomass with regard to BECCS after 2030 is availability. This availability is mapped by the model based on a review of the literature. As there is a considerable range in the numbers published around the average, and in order to explore the implications of this constraint, a sensitivity analysis respecting the NZ50 scenario was performed, using two alternative constraints:
- BioMin: biomass availability (e.g., forest and agriculture residues) for energy production is reduced by 50%.
- BioMax: biomass availability (e.g., forest and agriculture residues) for energy production is doubled.
The results show some changes in final consumption patterns. Overall, compared with NZ50, BioMin presents similar levels in 2030, but less consumption in 2050 (-11% compared with NZ50). In BioMax, consumption is 13% higher than in NZ50 for 2030, but does not increase further and even decreases by 5% from that level in 2050 and 2060. Although the opportunity to use more biomass in the short term helps reduce emissions, residual emissions from its burning become too significant to be sustainable as NZ targets approach.
When looking at consumption by sector, no changes are observed in buildings regardless of the scenario. In industry as well, changes are very limited, with around 8% less biomass used in BioMin, compared with NZ50 in 2050, being the most important change.
However, in the transport sector, the various scenarios introduced significant differences. Biomass consumption in BioMin is identical to NZ50 for 2030, but 10% less in 2050, again showing the importance of the availability constraint in BioMin on the longer term. In BioMax, changes are major: 50% more biomass is used in 2030 compared with NZ50, and 45% more in 2050.
Given this difference, a closer look is needed to determine where these changes operate. In passenger transport, BioMax shows 19% more biofuels in 2030 compared with NZ50 and results in almost five times as much biofuel in 2050. In other words, most of the change is over the longer term for passenger transport. In merchandise transport, BioMin is identical with NZ50 in 2030, but 20% less in 2050. However, BioMax shows a 38% increase over NZ50 in 2030 and a 100% higher value in 2050. Merchandise transport is much more affected than passenger transport by the opportunity to use more biofuels, in both the short and the long term.
Aviation sees a small decrease for BioMin in 2030 and levels 20% lower than NZ50 in 2050. BioMax levels are almost 10 times higher (2030) and 11 times higher (2050) than NZ50, but this remains a very small part of the total energy used by this sector (1% in 2030 and 5% in 2050).
The schedule for change is different in other transport sectors. Both rail and maritime transport use 40% more biomass in 2030 compared with NZ50, but levels are identical in 2050. A similar pattern is observed in off-road transport. This suggests that the additional biomass availability is useful in these sectors for short-term GHG reduction efforts but less so in the longer term.
A look at overall biomass use (Figure 9.3) provides a different angle on these increases. In 2030 and 2040, the increase in biomass use in BioMax is chiefly for biofuels and renewable natural gas (+80% and +200% over NZ50 in 2040, respectively). BioMin has the greatest impact in 2050 and 2060, reducing biofuels by 20% over NZ50 and renewable natural gas by 72%. As discussed above, BioMax sees both these applications decrease after 2040 as residual emissions from their burning become an important factor.
Figure 9.3 – Biomass use #
A final and crucial point is the impact of these alternative constraints on biomass availability on the negative emission activities, namely BECCS electricity and hydrogen production. Given the need for negative emissions in industry and in BECCS energy production to attain net-zero, the quantity of biomass available may play a key role both in the type of emission capture technologies used and in the requirements for DAC. BECCS electricity presents different levels than NZ50 from 2040 (less in BioMin and more in BioMax, as expected due to the availability constraint in each scenario), while BECCS hydrogen production is similar in all three scenarios. The different levels for BECCS electricity continue in 2050 when BECCS hydrogen production then also varies similarly, depending on BioMin or BioMax.
Overall then, changes to the structure of emissions are limited in the short term but become significant in 2050 (Figure 9.4). In BioMin, the need for DAC is increased as less BECCS is possible for negative emissions. In BioMax, no DAC is necessary and negative emissions are even more substantial (165 MtCO2e instead of 125 as in NZ50), allowing for more remaining emissions from other sectors (which come primarily from transport). The picture is similar for 2060.
Figure 9.4 – Emissions by sector #
General observations:
- The role of biomass availability in net-zero pathways is concentrated in the transport sector and in BECCS electricity and hydrogen production, with a direct impact on the possibility of negative emissions.
- In the transport sector, increasing biomass availability does not have a uniform impact over all subsectors: passenger transport is mainly affected in the longer term, while rail, maritime, and off-road transport are affected only in the short term; merchandise transport is affected at all times.
- More biomass leads to more BECCS, reducing pressure for the use of DAC when approaching net-zero; the opposite is true for a future with less biomass available, highlighting the need for careful management of this resource.
- From a system’s point of view, more biomass availability favours an increased use of biofuels in transport, which then requires more CCS obtained by using more biomass for BECCS electricity.