The world needs a large supply of renewable carbon to replace fossil feedstocks for hard-to-abate sectors like aviation, shipping, chemicals, food and beverage. Arno van den Bos, Karan Kochhar, Luis Janeiro and Francisco Boshell at IRENA present the results of their study to estimate demand, and whether supply can match it through to 2050. The main sources of supply come from alcoholic fermentation, biogas, pulp & paper, and biomass. Each has its own cost profile, and estimates of production capacity. Competition between customers for biogenic CO2 will be fierce, and estimates of demand are made. Aviation and shipping will need it for e-fuels, food will need it for fertilisers and beverages for carbonising drinks, the chemicals sector for feedstocks. And the emerging carbon removal sector may introduce huge demand for carbon usage. These are all rough estimates, say the authors, and more detailed studies are required. But it looks like total demand will exceed supply, and that high-concentration and low cost-biogenic CO2 in particular is a very scarce resource.
Transitioning the global economy to one that is compatible with limiting global average surface temperature rise to 1.5°C by 2050 requires eliminating almost all fossil CO2 emissions from all sectors of the economy. The International Renewable Energy Agency’s World Energy Transition Outlook 1.5°C scenario shows that while electrification with renewable energy can cover the bulk of decarbonisation, a significant share of emissions from hard-to-abate sectors (aviation, shipping and chemicals) cannot rely on electrification alone, and still requires a sustainable source of carbon-based fuels and feedstocks.
A sustainable source of carbon-based fuels and feedstocks
Sustainable sources of carbon have to be short-cycle, meaning that the carbon was taken from the atmosphere either indirectly through photosynthetic plants (biomass) or directly using direct air capture (DAC) technologies. Extracting CO2 from the air requires enormous amounts of energy, due to its relatively low concentrations. And while many technologies are competing to reduce the capture costs, DAC-CO2 is likely to remain very expensive in the foreseeable future.
It is therefore not surprising that e-fuel project developers chose to source their CO2 from biogenic sources with higher concentrations and much lower costs. As we develop long-term energy scenarios, an important question arises: will there be enough biogenic CO2 for all these demands by 2050?
Will there be enough Biogenic CO2?
Further research seems necessary to assess the long-term supply of, or demand for, biogenic CO2 on a global scale. Doing so requires detailed knowledge of industries that could supply it and of existing as well as emerging sectors that will need it. In this article we review the main potential sources of supply and demand for this valuable resource and aim to raise awareness of the many considerations that require attention from both industry and policy makers.
Sources of biogenic CO2 can be categorised according to their concentration (% CO2 in the gas), cost and scale. The higher the concentration of CO2, the lower the (energy) cost of extracting it. Capturing CO2 from very small-scale installations is usually not economically feasible.
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Table 1: Main sources of biogenic CO2 according to concentration and cost / SOURCE: BIP Europe, REGATRACE, Parkhi et. al (2022), Ericsson 2017
High concentration streams of biogenic CO2 are almost always a waste product of installations that were built for another purpose (such as providing power, heat, beverages etc.). At best, CO2 is a low-value by-product. This means that a higher demand for biogenic CO2 is unlikely to lead to much more supply.
Why CO2 from industrial point sources is prohibited
Let’s go over the main potential sources from which biogenic CO2 could be sourced by 2050. The largest medium concentration streams of CO2 can be found from industrial point sources. Unfortunately, most of these streams are the result of burning fossil fuels, or from other chemical processes that release carbon that was previously underground, like the calcination of limestone in cement making. These streams can be captured and stored in geological reservoirs as emission mitigation measures (CCS), but they do not qualify as short cycle carbon that can be used in short-lived products such as fuels (CCU). To reflect this reality, the second EU Delegated Act on GHG accounting for RFNBOs already prohibits their use beyond 2035. Therefore, only CO2 that results from the combustion of biomass, bioliquids or biogas, can be considered biogenic.
Main sources of supply
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Figure 1: Estimated global CO2 supply potential from different sources by 2050 / SOURCE: Authors estimates based on IRENA (2023), IEA (2023), IEA Bioenergy Task 40 (2020)
…Alcoholic fermentation
The most attractive source of biogenic CO2 is the highly concentrated stream that results from the alcoholic fermentation of sugars in the production of beer, cider, wine, and spirits. Based on global alcohol consumption and industry growth estimates, this could supply up to 39 Mt by 2050, assuming 90% of this stream could be recovered.
The question of how much of this waste CO2 can practically and economically be recovered is difficult to estimate and applies to the other sources of supply as well. Economic recoverability depends on many factors such as scale, local energy costs, ability to invest, advances in capturing technologies and availability of infrastructure to transport it to locations where it can be used. In the case of fermentation, it is unlikely that microbreweries will be able to capture the micro-CO2 streams and convert them into any kind of e-fuel. However, in the presence of a well-developed CO2-pipeline infrastructure, even small-scale sources may be able to combine their volumes to a centralized, larger-scale plant.
…Biogas
Climbing down the concentration scale, next in line is biogas. Biogas is a mixture of biomethane and biogenic CO2 in varying proportions. It can be burnt directly to generate electricity and heat, or upgraded to separate the CO2 from the methane that can be injected in natural gas grids. Assuming a CO2 content from 25% to 45%, and that up to 60% of it can be recovered from IRENA’s 16 EJ of biomethane in its 1.5 1.5°C scenario, this could lead to the production of 170-500 Mt of biogenic CO2.
…Pulp & Paper
The Pulp & Paper industry uses large amounts of biomass as feedstock but also as energy source, and for each tonne of paper, some 2 to 2.5 tonnes of CO2 are released. With the industry expected to more than double its production by 2050, this could lead to 900 to 1,800 Mt of biogenic CO2 being produced depending on capture rates.
…Biomass
IRENA’s 1.5°C Scenario has power generation from biomass at 743 TWh in 2050. Assuming 70% can be captured, this would result in over 500 Mt of biogenic CO2 to be potentially available. These numbers already account for some industrial heat generation by combined heat and power plants, but do not account for biomass-based heat from industrial boilers, nor for energy recovered from the biogenic fraction of waste incineration that could potentially bump this number by another 75 Mt. Residential biomass or biomethane use for heating is not considered, since the installations are too small to recover any meaningful amounts.
All these should be taken as rough initial estimates that require significant fine-tuning for strategic decision-making. Many of the estimates of supply are path dependent, and the ones gathered here are from different sources and scenarios that are not necessarily coherent amongst each other. The most important uncertainties lie in estimating how much CO2 is actually recoverable – as discussed above, but also on alternative uses and their economics.
Competition for Biogenic CO2 will be fierce
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Figure 2: Estimated CO2 required globally in different applications by 2050 / SOURCES: Authors estimates based on IRENA (2023), IEA (2023), Roland Berger (2024), Smeaton (2021)
On the demand side, a lot of attention has gone to shipping and aviation and their need for e-fuels to decarbonise. Unfortunately, they are not the only sectors that will lay claim on this resource. Beside sectors that have historically been using CO2 as a feedstock (think of bubbly drinks and urea fertiliser) some sectors that previously did not need them (chemical sector) or that didn’t even exist (carbon removals) will have to gobble up large volumes as well in a Net-Zero world.
…Food and Beverage, Greenhouses
Starting with the existing uses, in 2023, the global food and beverage industry used about 11 Mt of CO2, while greenhouses (mainly in the Netherlands) use up an additional 6 Mt. Assuming these sectors keep growing in line with population and economic growth, they could consume over 60 Mt of biogenic CO2 by 2050.
The larger existing use is for carbon-containing urea, which represents about 55% of global nitrogen fertiliser use. When applied to the field, all the carbon content of urea is released, so in a Net-Zero scenario the options are either to use alternative forms of nitrogen fertiliser (direct ammonia application, ammonia nitrates or sulphates), or to source the CO2 from biogenic sources, which could represent an additional demand of up to 118 Mt by 2050. So far, it is not clear which option will prevail, and to what extent.
…Shipping and Aviation
Shipping and aviation are notoriously hard to abate sectors. IRENA’s 1.5-degree scenario contemplates large shares of e-kerosene for aviation, and e-methanol for shipping, that could require up to 100 Mt for shipping and up to 500 Mt of renewable CO2 for aviation by 2050. While ships can retrofit their engines to burn e-ammonia (requiring the hard and costly task of modifying not only the engines, but also onboard fuel storage), the existing stock of aircraft really needs the carbon-carrying kerosene molecules. Biofuels are a good option for the short and maybe medium term, but they will likely be insufficient to address the 2050 demand from these sectors.
…Chemicals
The chemical sector uses roughly half of its fossil fuel inputs as a source of energy, and the other half as chemical feedstock. While the energy needs for heat and pressure can be largely electrified with renewable energy, the feedstocks will still require a sustainable source of carbon, sourced either directly from biomass or indirectly through e-chemicals that are derived from captured biogenic CO2 or direct air capture. If half of the carbon were to be sourced from biogenic CO2, this could represent more than 2,700 Mt of biogenic CO2.
…Carbon removals
And last but not least, most IPCC scenarios that are aligned with Net-Zero, include a large role for carbon removals, which include traditional nature-based solutions such as landscape preservation, reforestation etc, but also for direct air capture and BECCS, which competes directly for biogenic CO2 for volumes that could reach over 3,000 Mt by 2050 (and even more by the end of the century).
Based on these rough estimates, it looks not only like total demand will exceed supply, but that high-concentration and low cost-biogenic CO2 in particular is a very scarce resource.
Further considerations for policy makers
The scarcity of biogenic CO2 means that more detailed assessments of existing and potentially future sources are required with a regional and or country focus. Governments need to think about how to prioritise its uses, and e-fuel and chemical project developers better ensure their long-term access to the low-cost sources, if they don’t want to get it from expensive low-concentration sources, or worse, from direct air capture.
Apart from these important questions about supply, recoverability, and infrastructure, other discussions that have only partially been settled for biofuels and – more recently – low carbon hydrogen, on sustainability, certification, acceptable sources and uses need answers to provide investor confidence and build out the required infrastructure. What will be the sustainability criteria for renewable carbon? Should we measure, and if so, how, the carbon intensity of carbon? Before biogenic waste CO2 can be used, it needs to be compressed, stored and transported. These steps add a carbon footprint to biogenic CO2 from the moment it is emitted up to the point of use. What should be the maximum footprint? How should it be verified and tracked? The way renewable carbon is defined creates incentives that should be carefully considered.
The increased demand for renewable synthetic fuels can also be an opportunity for getting more out of our limited sources of biomass. Technologies known as Power and Biomass to Liquid (PBtL) or e-biofuels, allow for higher yields and efficiencies of Biomass-to-Liquid (BTL) plants by injecting renewable hydrogen in the process.
Zooming out, strategic aspects should be considered for industrial and trade policies: under what conditions should we be transporting CO2? Does it make more sense to ship higher value-added products such as e-fuels? Thousands of kms of pipelines exist around the world to transport natural gas. Should we repurpose them to transport hydrogen? CO2? Or e-methane, which can be decomposed at destination in any of these products? The dependence of e-fuels and e-chemicals – with the exception of ammonia – on biogenic CO2 means their role in decarbonisation cannot be detached from bioenergy scenarios.
Robust clarification of these points will require more in-depth analysis and attention to inform policy decisions.
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Arno van den Bos is an Analyst at IRENA
Karan Kochhar is an Associate Programme Officer at IRENA
Luis Janeiro is a Team lead, End use sectors at IRENA
Francisco Boshell is Head Innovation and End Use Applications at IRENA