What does net-zero emissions by 2050 mean for bioenergy and land use?

Modern and sustainable forms of bioenergy play an important role in our new special report on how the global energy sector can reach net-zero emissions by 2050, which also examines bioenergy’s advantages and limitations in efforts to address climate change by limiting the rise in global temperatures to 1.5 °C.

Bioenergy is a versatile renewable energy source that can be used in all sectors, and it can often make use of existing transmission and distribution systems and end-user equipment. But there are constraints on expanding the supply of bioenergy, and possible trade-offs with sustainable development goals, including avoiding conflicts at local level with other uses of land, notably for food production and biodiversity protection.

To navigate these risks, our Roadmap to Net Zero by 2050 combined for the first time the IEA’s global energy system modelling with the International Institute for Applied Systems Analysis (IIASA)’s Global Biosphere Management Model to provide insights on bioenergy’s supply, land use and net emissions.

We aimed to ensure that the peak level of total primary bioenergy demand – including losses from the conversion of biomass into useful fuels – falls within the lowest estimates of global sustainable bioenergy potential in 2050, namely around 100 exajoules (EJ). Bioenergy demand in our global net zero pathway – the Net-Zero Emissions by 2050 (NZE) Scenario – is lower than all comparable scenarios from the Intergovernmental Panel on Climate Change (IPCC) that are aligned with 1.5 °C. Those IPCC scenarios use a median of 200 EJ of bioenergy in 2050. 

Total bioenergy supply in the Net-Zero Emissions by 2050 Scenario relative to comparable IPCC scenarios

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In the NZE Scenario, bioenergy rapidly shifts to 100% sustainable sources of supply, and sustainable use. There is a complete phase-out of the traditional use of solid biomass for cooking, which is inefficient, often linked to deforestation, and whose pollution was responsible for 2.5 million premature deaths in 2020. The traditional use of solid biomass –estimated at around 40% of total bioenergy supply, or around 25 EJ, today – falls to zero by 2030 in the NZE Scenario, in line with achieving UN Sustainable Development Goal 7 on universal access to affordable, reliable, sustainable and modern energy for all.

The use of conventional biofuels, which are produced from food crops, is also significantly reduced by 2050. Like all other aspects of the energy transition in the NZE Scenario, the pathway to ensuring bioenergy sustainability is challenging but achievable. It requires concerted government actions to control the sustainability of bioenergy supply, facilitate the transition to advanced bioenergy, and maximise the efficiency of bioenergy production processes and use.

Sustainable use of bioenergy in the NZE Scenario not only avoids negative impacts such as increased deforestation and competition with food production – it also delivers benefits beyond the energy sector. Shifting from traditional use of biomass to modern bioenergy can avoid undue burdens on women often tasked with collecting wood for fuel, bring health benefits from reduced air pollution and proper waste management, and reduce methane emissions from inefficient combustion and waste decomposition.1 More generally, sustainable bioenergy can provide a valuable source of employment and income for rural communities in emerging economies.

Of the total global bioenergy demand in 2050, around 60% is solid bioenergy, almost 30% is liquid biofuels, including energy use for their production, and over 10% is biogases. Demand is concentrated in sectors that are either hard to electrify, or require a low-cost dispatchable source of renewable energy.

In the electricity sector, solid bioenergy demand in 2050 is around 35 EJ. Bioenergy provides only 5% of total electricity generation in 2050, but it is an important source of low-emissions flexibility to complement variable generation from solar PV and wind. In the industry sector, where solid bioenergy demand reaches 20 EJ in 2050, it is used to meet high temperature heat needs that cannot be easily electrified such as paper and cement production. In 2050, bioenergy meets 60% of energy demand in the paper sector2 and 30% of energy demand for cement production. In the buildings sector, bioenergy demand increases to nearly 10 EJ in 2030, mostly in emerging economies for improved cookstoves that replace unsustainable traditional uses of biomass.

Bioenergy demand in the Net-Zero by 2050 Scenario, 2010-2050

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Biogas3 use reaches 14 EJ in 2050 in the NZE Scenario. Biomethane demand grows to 8.5 EJ, thanks to blending mandates for gas networks, with average blending rates increasing to above 80% in many regions by 2050. Half of total biomethane use is in the industry sector, where biomethane replaces natural gas as a source of high temperature process heat. The buildings and transport sectors each account for around a further 20% of biomethane use. In addition, household and village biogas digesters in rural areas provide a source of renewable energy and clean cooking for nearly 500 million households by 2030 in the NZE Scenario. Biogas digesters also play an important role in waste management, with major positive health impacts.

Liquid biofuel consumption rises from 1.6 million barrels of oil equivalent (mboe/d) in 2020 to 6 mboe/d in 2030 in the NZE Scenario, mainly for use in heavy duty trucks. Sustainable biofuels can use existing distribution networks for petroleum derived fuels and be used in vehicles with only minor or no alterations. This enables them to decisively cut road freight emissions over the next decade to help keep the world on track for net-zero emissions. At the same time, electricity- and hydrogen-fuelled vehicle models need to be scaled up to account for over 50% of truck sales by 2030. After 2030, liquid biofuel use grows more slowly to around 7 mboe/d in 2050, 90% of which is advanced biofuels – up from less than 1% today. As electricity increasingly dominates road transport, the use of advanced liquid biofuels shifts to areas that are harder to electrify, such as shipping and aviation. Starting in the late 2020s, advanced liquid biofuels start to make important contributions to reducing emissions from aviation, where alternative low‐carbon options are limited. In 2030, biojet kerosene, a drop‐in substitute for jet kerosene, accounts for almost 15% of total fuel consumption in aviation, and by 2050 almost half of liquid biofuel use is for aviation.

Bioenergy with carbon capture and storage (BECCS) plays a critical role in the NZE Scenario by offsetting emissions from sectors where full decarbonisation is extremely difficult to achieve. In 2050, around 10% of total bioenergy is used in facilities equipped with carbon capture, utilisation and storage, and around 1.3 billion tonnes of CO2 is captured using BECCS. Around 45% of this CO2 is captured in biofuels production, 40% in the electricity sector, and the rest in heavy industry, notably cement production

In the NZE Scenario, over 60% of the 100 EJ of global bioenergy supply in 2050 comes from sustainable waste streams that do not require dedicated land use (compared with 20% today). This includes agriculture residues, organic municipal waste, and forestry industry residues. Of these sustainable waste streams, forestry residues from wood processing and forest harvesting provide 20 EJ of bioenergy in 2050 in the NZE Scenario. This is less than half of current best estimates of the total technical potential. Investment in comprehensive waste collection and sorting in the NZE Scenario unlocks close to 45 EJ of bioenergy supply from various sustainable waste streams outside of the forestry sector. This is primarily used to produce biogases and advanced biofuels.

The remaining 40 EJ of bioenergy supply in the NZE Scenario in 2050 requires land use – compared with 25 EJ from bioenergy crops and forestry plantations that require land use today.4 However, there is no overall increase in cropland5 use for bioenergy production in the NZE Scenario, and no bioenergy crops are developed on forested land.

To avoid conflicts between food production and affordability, there is a general shift away from the use of food crops for bioenergy. These feedstocks are often known as “conventional” bioenergy feedstocks. The use of conventional energy crops grows marginally between 2020 and 2030 but then falls to below 3 EJ by 2050 with the transition towards advanced ethanol, advanced biodiesel and biokerosene, and the combination with carbon capture and storage. The focus is on producing bioenergy from dedicated short-rotation woody crops  grown on cropland, pasture land or marginal lands not suited to food crops. These provide 25 EJ of bioenergy supply in 2050 in the NZE Scenario. As well as allowing a much greater level of bioenergy crop production on marginal lands, short-rotation woody crops can produce twice as much bioenergy per hectare as many conventional bioenergy crops. 

A further source of bioenergy supply is sustainably managed forestry plantations and tree plantings integrated with agricultural production via agroforestry systems that do not conflict with food production or biodiversity. Sustainably managed forest plantations established outside of existing forested land can increase carbon stocks while at the same time sustainably produce biomass. These provide just over 10 EJ of bioenergy in 2050.

Global bioenergy supply in the Net-Zero by 2050 Scenario, 2010-2050

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The total land area for bioenergy production in the NZE Scenario increases by 80 million hectares (Mha) by 2050. Of the increase, 30 Mha are new forests, expanding global forest area by 1% so that bioenergy forest plantations represent 6% of total global forest area in 2050, the same share as today. Short-rotation woody bioenergy crops account for the remaining 50 Mha increase in land use for bioenergy by 2050. The 50 Mha increase sees the total land use for both short-rotation woody crops and conventional bioenergy crops rise to 140 Mha in 2050. Of this, 70 Mha are on marginal lands or pastures, and 70 Mha are on cropland, an area the same as today’s use of cropland for bioenergy production.6

Total land use for bioenergy in the NZE Scenario is below estimated ranges of potential land availability that take full account of sustainability constraints, including the need to protect biodiversity hotspots and to meet UN Sustainable Development Goal 15 on biodiversity and land use, notably via a drastic curtailment of deforestation. The certification of bioenergy products and strict control of what land can be converted to expand forestry plantations and short-rotation woody bioenergy crops is nevertheless critical to avoid land-use conflict issues.

Reaching net-zero CO2 emissions from energy and industrial processes in the NZE Scenario does not rely on any offsets from outside the energy sector. However, agriculture, forestry and other land use (AFOLU) is today responsible for around 5-6 billion tonnes of CO2 emissions, and is therefore the second largest source of emissions after the energy sector. These emissions also need to be addressed to limit climate change. While measures to address AFOLU emissions are not explicitly part of the NZE Scenario, given its focus on emissions from the energy sector and industrial processes, the increase in short-rotation woody bioenergy production from marginal lands and pasture land, as well as the switch from conventional bioenergy crops to advanced short-rotation woody crops, would sequester around 190 million tonnes of CO2 by 2050, reducing AFOLU emissions by 140 million tonnes of CO2 relative to today.

Nonetheless, other levers would be needed to fully eliminate CO2 emissions from AFOLU. Reducing deforestation by two-thirds by 2050, instituting improved forest management practices for bioenergy plantations and other forests, and planting around 250 Mha of new forests would see CO2 emissions from AFOLU become net negative by 2040 and absorb 1.3 billion tonnes of CO2 annually by 2050.

The assessment of the availability of sustainable biomass feedstock and sustainability governance are important pillars of the planned work plan of the Biofuture Platform. This initiative, which is facilitated by the IEA, aims to establish a transparent dialogue among different stakeholders – including governments, international organisations, companies, non-governmental organisations and groups in the IEA Technology Collaboration Programme. The objective is to increase consensus on the complex topic of bioenergy sustainability and identify concrete solutions based on best practices in land-use management and technology innovation.

This commentary also benefited from the input of Stefan Frank, Nicklas Forsell and Mykola Gusti from IIASA; and Paolo Frankl, Timothy Goodson, Praveen Bains and Christophe McGlade from IEA.

References
  1. IEA, 2017; IEA, IRENA, UNSD, World Bank, WHO, 2020

  2. Refers to the pulp and paper sector.

  3. Biogas is a mixture of methane, CO2 and small quantities of other gases produced by anaerobic digestion of organic matter in an oxygen free environment. Biomethane is a near pure source of methane produced either by removing CO2 and other contaminants from biogas or through the gasification of solid biomass (IEA, 2020b).

  4. This excludes the traditional use of biomass, the majority of which is biomass harvested unsustainably from forests that are not dedicated bioenergy plantations, or bioenergy recovered from waste streams.

  5. “Cropland” here refers to agricultural land used for food, animal feed and bioenergy production but excludes short-rotation woody crops not established on existing agricultural cropland.

  6. There is a 60 Mha increase in cropland use for short-rotation woody crops to 2050 in the NZE Scenario, but this is more than offset by a reduction in cropland use for producing conventional biofuel feedstocks.