Bridging the gap to a sustainable future
Why advancing the biorefining platform is essential for a carbon-neutral world
Contents 1 Executive summary 4 2 The green energy matrix 6 3 The biorefining platform 8 4 Sustainable use of bio- feedstock within global limits 18 5 Biorefining’s current and potential future contributions 20 6 Conclusions 24 7 References 25 8 Appendix A: Overview of biorefining technologies 27 9 Appendix B: Overview of transport technologies 29 10 Appendix C: Life cycle GHG emissions from light duty vehicles (without CCS) 32 11 Appendix D: Life cycle GHG emissions from light duty vehicles (with CCS) 35 12 Appendix E: The IEA 2-degree scenario (2DS) 42 13 Appendix F: Estimation of average life cycle emissions from European ethanol 46 4 Bridging the gap to a sustainable future
1. Executive summary
The world is only at the beginning of a transformative battle against climate change. To win, small-scale changes driven by individuals or individual companies are not enough. We need to commit to industrial strategies and policy frameworks that can deliver both economic growth and lower carbon emissions.
What’s more, we need to take action today. Global carbon emissions hit a record high in 2017. With the
current trajectory, the CO2 budget leading to a 2-degree Celsius rise may be exceeded within the next 20 years. And with the rising temperatures comes a higher probability of extreme climate events at enormous cost and suffering.
What can we do to move faster towards finding solutions to climate change?
It is clear that there is no silver bullet. The most effective pathway to decouple economic growth from energy consumption and GHG emissions must include multiple technologies working together. This is especially true in those sectors that are hard to abate. The path forward is of course difficult to define without clear identification of end points, and without knowing which technologies will eventually succeed in the marketplace.
Using expert energy analyses of future scenarios that achieve a climate target of maximum 2-degree temperature rise, we present a vision that defines a pragmatic yet radical path forward. This vision unites green technologies in an energy matrix that capitalizes on the complementarity of green electrons and green carbon. The technologies are used to produce power, fuel, and hydrocarbon feedstock useful in many different sectors.
A key first battlefield for reducing carbon emissions is today’s transport sector.
Transportation accounts for about 25% of total energy-related global CO2 emissions, and its contribution will only increase with time. Carbon-neutral electrification of, for example, passenger cars holds great promise as a solution for decarbonizing transport. The technology and its commercialization have made impressive strides in the last two decades. We should continue to encourage its aggressive growth.
But the route of carbon-neutral electrification cannot succeed on its own in the time we have to mitigate climate change.
Economic growth in developing countries could double the number of passenger cars from 1 to 2 billion in just a few decades, and other types of transport are not as easily electrified. This means a continued dependence on liquid fuels for a long time to come.
Thus many energy analyses agree that additional solutions are necessary to complement carbon-neutral electrification. These include better engine efficiency, sustainable low-carbon fuels, and developments in drive systems for road, sea, and air transport.
Even if all but niche segments in transport are electrified in the future, there will still be demand for green hydrocarbon feedstocks for chemicals and materials. The best way to make sure those feedstocks are competitive in the long term is to use and facilitate the power of scale from low-carbon fuel technologies today. Bridging the gap to a sustainable future 5
Our vision is more than a set of complementary weapons for the battle against climate change. It is also rooted in what we know works. For each of the key solutions, there is already a portfolio of technologies proven at commercial scale. The cost of most of these technologies is often higher compared to the fossil fuel option. But the reason is simply that they haven’t been optimized continuously for more than a century like the petrochemical industry. The good news is that experience and investment will bring costs down, and the development of new industries will bring global economic growth.
The good news doesn’t stop there. The complementary relationship between carbon-neutral electrification and sustainable bio-based technologies can prove useful in supporting integrated solutions that would improve efficiency, reduce costs, and increase reliability throughout the entire energy matrix. For example, the intermittency of wind and solar could be balanced by storable solid or
gaseous fuels, co-produced with liquid fuels from sustainable bio-feedstocks. And CO2 captured from biorefineries can be used with hydrogen from renewable electricity in power-to-X processes that further enable long-term energy storage, provide low-carbon fuels, and improve biorefining carbon efficiency.
Alternatively, captured CO2 can be stored to generate negative emissions, which will most likely be needed to achieve international climate targets.
Ultimately, our vision is centered around the complementarity of green technologies in an energy matrix that can boost economic growth and jumpstart our journey towards addressing climate change. The following report describes how sustainable biorefining is an integral piece in this vision, and how urgently we need to advance the industry to meet international climate targets.
We invite all stakeholders to join us in this vision and to extend it with their own. We also urge industry, government, financial institutions, and research organizations to hasten the continued development and deployment of such technologies through collaboration and policy frameworks. The battle may be difficult, and there may be friction between allies, but these are surmountable obstacles that should not deter us from our common goal.
This document is available at www.novozymes.com/bioenergy for all to access and use without restrictions. 6 Bridging the gap to a sustainable future
2. The green energy matrix
Central to our vision is an energy matrix of complementary green technologies (Fig. 1). The majority of the technologies are proven at commercial scale and play major roles in expert analyses that outline what’s needed to limit global temperature rise to 2 degrees. This illustration is limited in scope to end-use only in the transport, chemical and feed sectors. Our vision, on the other hand, is based on expert analyses that address a broader scope including all uses of heat, power, and fuels.
Wind turbines and solar photovoltaics are the primary source of renewable power in the green energy matrix. Broad consensus is that a future carbon-neutral economy relies heavily on these technologies. To actually achieve a carbon-neutral economy will require significant growth of these technologies, along with solutions to balance daily and seasonal fluctuations.
Combined heat and power (CHP) plants based on sustainably-sourced biomass are an immediate solution to phase out coal (where relevant) and provide flexibility. In the future, as wind and solar electrification comes to drive the power and heating sectors, biomass CHP may become an important source of electricity to balance longer-term fluctuations.
Biorefining based on sustainably-sourced bio-feedstock is the primary source of low-carbon fuels in the envisioned green energy matrix. Its products are available today, and offer low-carbon alternatives to replace or blend with typical petroleum-based products such as gas, liquid fuels, and hydrocarbon feedstocks for chemicals and materials. Additional details on biorefining technologies are available in Appendix A.
Power-to-X is a promising portfolio of technologies and pathways that in the future could offer long-term energy storage. Power-to-X utilizes renewable power to produce hydrogen via electrolysis. The hydrogen can then be stored and reconverted to power, or it
can be further processed with CO2 to yield a wide range of hydrocarbon products, including fuels and hydrocarbon feedstocks.
Carbon-capture and storage (CCS) or utilization (CCU) is likely an important contributor towards sufficient reduction in carbon emissions. When combined with biorefining or biomass-fired power stations, CCS (in this case called BECCS) enables negative carbon emissions. According to most IPCC emission scenarios, negative carbon emissions are needed to meet a target of maximum 2-degree temperature increase. Bridging the gap to a sustainable future 7
Additional valuable technologies
Not shown in the illustrated matrix are other GHG-neutral energy sources, as well as solutions for future grid management:
Hydro power is a major source of power in relevant regions. It will likely continue to be so in the future, particularly as a solution to balance an electricity grid powered by variable wind and solar.
Nuclear power is generally considered a reliable base load source of electricity, given its low variable costs and high fixed costs. In the future, there will likely be improvements in the adaptability of nuclear power plants to be able to adjust to variations in power supply and demand.
Battery power storage, long-distance power transmission, and demand-side management in a smart grid are technologies that hold significant potential in the future as economical solutions for energy management.
Wind Windpower
Sun Solarpower Balanced smart grid
Bio-feedstock CHP
CO
Combustibles and/or biogas Power-to-X
Carbon storage
Biorefinery Liquid and gaseous fuels
Materials and feed
Fig. 1: The green energy matrix 8 Bridging the gap to a sustainable future
3. The biorefining platform
The appeal of biorefining rests on the utilization of nature’s own intelligent carbon-capture technology. Because of this, biorefining plays a crucial role in the reduction of global carbon emissions and holds great potential to continue delivering even lower carbon emissions in the future.
The biorefining platform is important not only for achieving carbon emission reductions but also for the value it brings to the overall vision of a green energy matrix that fosters economic growth. It delivers a unique complementarity with other green technologies. And very importantly, it offers a complementarity that can be adapted over time.
Time is a critical dimension because of the immediate and urgent need for action against climate change. A separate challenge is that future shifts in energy demand and supply are hard to predict. Biorefining is an ideal technology to tackle both challenges.
A biorefinery is defined as a facility that transforms bio-feedstocks into fuels, power, heat, feed and other value-added compounds such as chemicals and materials. A wide variety of conversion processes are possible at a biorefinery. These include anaerobic digestion, gasification, Fischer-Tropsch synthesis, enzymatic hydrolysis, and fermentation. As long as sustainable feedstock is used, the biorefinery can represent any one of these processes within the envisioned green energy matrix.
Our vision for the biorefining platform is an important one within the overall vision of a carbon-neutral energy matrix in the future. It is based on the biochemical process of converting sugar, starch, and cellulosic material to fuels and materials. The central elements of the biorefining vision are:
Complementarity in energy supply and demand • The central role of biorefining is due to its complementarity in two ways: in the supply of energy, and in the end-use of its products. In terms of end-use, biofuels will typically be one step ahead in serving hard-to-electrify transport segments. In terms of energy supply, biorefineries will enable mutually beneficial material and energy flows.
Adaptability and scalability • The sugars produced from enzymatic conversion are today most commonly fermented at commercial scale to produce bioethanol as well as co-products of animal feed (from starch feedstocks) and lignin (from cellulosic feedstocks). Over time however, these processes can evolve to include other downstream processes that yield a variety of green hydrocarbon fuels as well as feedstocks for chemicals and materials. This versatility of sugars as platform molecules gives the biorefinery its unique ability to adapt to future changes in demand.
• A benefit of the evolution from bioethanol to bio jet fuel and biochemicals is that the initial bulk application (ethanol) accelerates learning-curve cost reductions and economies of scale.
Carbon capture viability
• The high-concentration stream of CO2 emitted from (anaerobic) fermentation processes translates into a low-cost way to capture carbon. Carbon pricing that facilitates deployment of carbon capture and storage technologies at a biorefinery could enable negative carbon emissions, which are essential to keep global temperature increase below 2 degrees Celsius in almost all climate scenarios.1
1 http://www.nature.com/articles/ncomms8958 Bridging the gap to a sustainable future 9
Biorefining technology based on enzymatic conversion is relatively mature, with commercial plants operating on both starch and cellulosic feedstock. However, continued development and lower production costs will require renewed investment in biorefining and strong policy frameworks. A key driver of our vision is therefore to establish a coalition working towards frameworks that support a sustainable biorefining platform, such as carbon pricing and clear long-term targets for sustainable biofuels in transport.
3.1 Complementarity in a portfolio of green technologies
The biorefining platform plays an integral role in bringing together the envisioned green energy matrix, and achieving its complementarity in both the supply and demand of energy.
In the production of energy, the biorefining platform is valuable as a source of storable heat and power to balance intermittent power generation. Battery technology may be sufficient to economically stabilize sub-second or intraday variability, but storage of co-products from biorefineries (e.g., biogas, lignin, and vinasse) can provide longer-term low-cost grid stabilization. Additional details can be found in the International Energy Agency (IEA) report Bioenergy’s role in balancing the electricity grid and providing storage options – an EU perspective (IEA, 2017c).
Another complementarity in energy production is the combination of renewable hydrogen with CO2 captured from biorefining in power-to-X processes. Hydrogen produced from the electrolysis of water
using renewable power can be further processed with the CO2 to yield a wide variety of hydrocarbon fuels or feedstocks for chemicals and materials. This complementarity improves the carbon efficiency as well as the economics of both biorefining and intermittent power generation.
The end-use of biorefining products in the transport sector is complementary with other important ways to reduce GHG emissions, such as improved fuel efficiency and electrification. Both sustainable biofuels and electrification have immense potential for emissions reductions, but both also have their limits. The amount of sustainable biological feedstock (most likely 100-300 EJ by 2050) limits the extent to which biofuels can replace fossil fuels. The growth rate of electrification may well be impressively steep, but its dominance in the light-duty fleet is hindered by two factors: vehicle lifetime and a simultaneous steep increase in total number of cars2. Combustion engines will thus continue to outnumber electric motors in the light-duty fleet for at least the next two to three decades (Fig. 2), even under more aggressive projections of electric vehicle adoption.
2 Morgan Stanley Research: On the Charge, 2017. 10 Bridging the gap to a sustainable future
1,6
1,4
1,2 BEV
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Billion LDVs 0,6
0,4
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0,0 2015 2020 2025 2030 2035 2040 2045 2050 2055
Today IEA RTS BP
UBS base case IEA 2DS Wood Mackenzie Base case
UBS upside IEA B2DS Wood Mackenzie Carbon-constrained case
UBS downside Bloomberg New Energy Finance OPEC
Fig. 2: Global light-duty fleet of battery electric vehicles (BEV), and vehicles with internal combustion engines (ICE) including hybrids. Lines represent the Morgan Stanley base case. Points represent other projections
Growing demand for fuel is also expected in sectors beyond light duty. Hard-to-electrify transport, such as heavy-duty trucks, ships and aviation, are projected to be significant drivers of oil demand growth in the coming decades. These sectors are expected to contribute over half of transport GHG emissions in the future (IEA, 2016) and will continue to rely predominantly on liquid fuels for an even longer period than the light-duty sector. These liquid fuels, which largely must be more energy dense than bioethanol, are also products of biorefineries. For example, the biorefining process can yield drop-in quality gasoline, diesel, and jet fuel that are chemically identical to their petroleum-based counterparts (Appendix A).
In hard-to-electrify transport, sustainable biofuels are not only useful as a drop-in fuel for conventional drive trains based on combustion engines, but also as a fuel that is complementary with new drive system developments. Examples of innovation in biofuel-based drive system technologies include:
• Ethanol fuel cells for light-duty vehicles3 as well as other types of transport • Flex-fuel vehicle engines, including inexpensive ethanol conversion kits that allow conventional engines to operate on any blend of ethanol and gasoline4 • Diesel truck engines adapted for ED95 (95% ethanol with the addition of ignition improver, lubricant and corrosion protection)5 • Flex-fuel ship engines6 that enable the use of more sustainable fuels such as ethanol or ethanol blends Further descriptions of vehicle technologies are given in Appendix B: Overview of transport technologies.
3 http://www.autonews.com/article/20160614/OEM05/160619961/nissan-develops-new-ethanol-fuel-cells-to-jump-infra- structure-hurdle 4 https://eflexfuel.com/en 5 https://www.scania.com/group/en/scania-is-ready-for-the-rise-of-ethanol/ 6 https://marine.man-es.com/two-stroke/2-stroke-engines/me-lgi-engines Bridging the gap to a sustainable future 11
3.2 Adaptability and scalability of biorefineries
The ability of the biorefining platform to evolve over time is based on its compatibility with many types of downstream processing (cf. Appendix A: Overview of biorefining technologies). Downstream processing of sugars includes (but is not limited to):
• Fermentation to ethanol or higher alcohols, e.g. isobutanol (Kang and Lee, 2015) • Further processing (i.e. catalytic conversion) of alcohols to other hydrocarbon fuels (e.g. gasoline, diesel, jet fuel) and chemicals 7 • Chemical catalysis or combination of biological and chemical catalysis of sugars to hydrocarbon fuels and chemicals (Anbarasan et al., 2012; NREL, 2013)
Co-products from biorefining also create value. For example, today’s starch-based biorefineries produce protein-rich animal feed for the livestock sector. Corn ethanol plants also produce corn oil that can be used in animal feed or to produce biodiesel. Side streams from cellulosic biorefineries include off-gas or flue gas from the thermochemical process, or lignin and biogas from the biochemical process – all of which can be used flexibly for heat and power in the integrated energy matrix. In the case of enzyme- based cellulosic biorefineries, there is sufficient lignin and biogas to both satisfy the energy demand of the biorefinery itself and be used as storable feedstock for grid stabilization.
Fig. 3 represents an example of how an integrated cellulosic biorefinery can be configured.
Ethanol Straw Ethanol production 0.30 l/kg straw*
Lignin
Electricity and steam
Vinasse Combined heat and Excess electricity power (CHP) 0.27 kWh/kg straw*
Electricity CO2 0.7 kg/kg straw* Biomethane Biogas production 58 I/kg straw* and upgrade Biofertilizer
*Dry matter
Fig. 3: Possible configuration of an integrated cellulosic biorefinery. The figure illustrates outputs per kilogram of dry matter feedstock. Additional details are available in Kløverpris et al. (2016a). Not shown is output of excess heat (for industrial use
or district heating). CO2 estimate potentially available for CCS/U is based on Appendix D (assuming a 90% capture rate and considering energy use for capture, compression, transport, etc.)
7 https://www.energy.gov/sites/prod/files/2015/07/f24/wyman_bioenergy_2015.pdf 12 Bridging the gap to a sustainable future
The versatility of sugars as platform molecules gives the biorefinery its unique adaptability in the future energy system. For the transport sector in particular, this versatility is crucial. The scale and the relative volumes of different types of liquid fuel will change, perhaps dramatically, over time. Fig. 4 provides an illustration of how the biorefining platform can adapt to the hypothetical case where electrification grows from light-duty transport through those transport segments that are harder to electrify.
Production cost of barrel of sugar equivalent
Time
Fuels
Electricity
Feed / food / chemicals / materials
Carbon capture
Fig. 4: The adaptability of the biorefining platform over time. Size of circles represent relative increases or decreases in product volumes for the specified application.
Currently and in the near-term future, the outputs from enzyme-based biorefining are bioethanol and proteins (starch-based biorefining), along with co-produced heat and power (cellulosic biorefining). As light-duty road transport becomes increasingly electrified, biorefineries can adapt their process to transform the same feedstock to produce liquid fuels with higher energy density for heavy-duty road and marine transport. Even if electric motors eventually dominate all transport except aviation, the same biorefineries can shift production to jet fuels. If the technology of fuel cells becomes widespread in electrified transportation, bioethanol can be used instead of hydrogen as a less infrastructure-intensive fuel for fuel cells8. Finally, if combustion in transport is limited to niche applications and long-haul aviation, the biorefining process can shift its process to produce chemicals, materials, or proteins. There is also flexibility in the processing of co-produced lignin beyond its use as storable feedstock for electricity generation, as the technology to convert lignin to higher-value products continues to develop9,10,11,12.
8 https://fuelcellsworks.com/news/nissan-completes-first-phase-of-testing-on-its-bio-ethanol-fuel-cell-vehicle-in-brazil 9 http://www.biofuelsdigest.com/bdigest/2017/08/16/metgen-sweetwater-unlocking-lignin-the-roughest-toughest-orni- erist-material-that-ever-bushwhackd-a-pioneer-in-the-valley-of-death/ 10 http://www.biofuelsdigest.com/bdigest/2018/02/22/somethin-from-just-about-nothin-the-digest-2018-multi-slide-guide- to-upgrading-biorefinery-waste-lignin-into-bioplastics/10/ 11 http://www.greencarcongress.com/2013/03/maersk-20130320.html 12 https://news.vattenfall.com/en/article/preem-and-vattenfall-collaborate-biofuel Bridging the gap to a sustainable future 13
The key benefits of the adaptability of biorefining are essentially two-fold. First, products are prioritized at the appropriate time for the appropriate applications and regions. Second, initial focus on “easy” bulk applications (i.e., ethanol for light-duty road transport) instead of more complex and/or niche endeavors (e.g., jet fuel and chemicals) enables economies of scale and learning-curve cost reductions early in the process. Those gains can then be used when moving into increasingly complex technologies and higher value products. As a corollary benefit, the initial prioritization of ethanol avoids compounding the degree of technical risk from including too many immature technologies. Furthermore, the speed of electrification in transport does not alter the positive impact of the biorefining platform. Even if the number of electric vehicles surpass that of internal combustion vehicles in light-duty transport within the next two decades13, the adaptability of biorefining would still be critical during the transition period and beyond.
The focus in this paper has thus far been on the benefits arising from the adaptability of the biorefining platform. However, there are many other benefits of the biorefining industry in general:
Immediate reduction of GHG emission by displacing fossil fuels Bioethanol can reduce GHG emissions by 40-130% when compared to gasoline, depending on feedstock and process. This is when taking indirect effects (for biofuels production as well as gasoline displacement) into account. Savings above 100% can be obtained if feedstock production leads to carbon sequestration in soils, and if co-products provide GHG benefits in addition to the gasoline displacement (e.g., when co-produced bioelectricity displaces electricity on the grid). When carbon-capture and storage (CCS) is implemented in future biofuels production, GHG savings will be even higher. Additional detail about life-cycle GHG emissions from ethanol is available in Section 5 and Appendices C and D.
Reductions in total vehicle GHG emissions Bioethanol blends can reduce life-cycle GHG emissions from the existing fleet of cars with internal combustion engines (ICEs) during the transition to electrification. In fact, a high blend (E85) of 50/50 starch- and cellulosic-based ethanol could reduce the life-cycle GHG emissions of an ICE car to the same level as an electric car running on a projected post- 2020 average mix of EU electricity. This shows how bioethanol and electrification can work in tandem to decarbonize transport. In the long run, an ICE car could have net negative emissions over its full life cycle if running only on ethanol produced with CCS14. Additional details are available in Appendices C and D.
Ethanol as a high-octane source to resist pre-ignition (or ”knocking”) Ethanol is an alternative and cleaner source of octane, which is needed for proper functioning of modern engines and to support the introduction of more efficient engine technologies. Use of ethanol as an octane source reduces dependence on toxic and carcinogenic petroleum-based options.
13 Which is currently not expected (cf. Fig. 2) 14 Currently, ICE cars cannot run on 100% bioethanol so the example represents ‘an extreme’ to illustrate the potential full impact. A similar ‘extreme’ is illustrated in Appendix C and D with an electric vehicle running on 100% wind energy 14 Bridging the gap to a sustainable future
Reduced air pollutant emissions from biofuels The number of air pollutants and their complex interactions imply that pollution effects vary depending on local weather conditions and atmospheric composition. However there is consensus that replacing fossil fuels with bio-based fuels is beneficial. Replacing fossil diesel with ED9515 in heavy-duty transport results in lower emissions of NOx, particulate matter, and non-methane volatile organic compounds (IVL, 2015). In the case of ethanol blending in light-duty vehicles, two new studies16,17 that will be published in 2018 show that higher ethanol blends reduce emissions of particulate matter by an average of 50% over E10, and reduce NOx emissions by 10-30%. Much of the reduction is attributable to the replacement of aromatics with ethanol as the octane source.
Reduction in the unsustainable use of bio-feedstocks for cooking In developing economies, substituting liquid fuels such as ethanol for cooking instead of charcoal or wood reduces deforestation and improves health due to reduced indoor smoke. The Global Alliance for Clean Cooking18 and Project GAIA19 both promote clean cooking.
Positive socio-economic impacts leading to economic growth, such as: • Local and national energy security because of reduced dependence on foreign oil production (Demirbas 2017) • Rural diversification and additional value from products already in a local economy (Demirbas 2017)
Unfortunately, the many advantages of the biorefining platform are often misguidedly offset by the controversies surrounding biological feedstocks. These are discussed in the section titled “Sustainable use of bio-feedstock within global limits”.
15 Fuel containing 95% ethanol and 5% ignition improver, lubricant, and corrosion protection, www.sekab.com/biofuel/ed95/ 16 https://fixourfuel.com/wp-content/uploads/2018/04/NCSU-Study.pdf 17 https://fixourfuel.com/wp-content/uploads/2018/04/UC-Riverside-Study.pdf 18 http://cleancookstoves.org/ 19 https://projectgaia.com/ Bridging the gap to a sustainable future 15
3.3 Carbon capture viability
Carbon capture and storage (CCS) is the technology of capturing CO2 directly from the atmosphere or
from point sources (e.g., power plants and biorefineries). The CO2 is stored in underground geological reservoirs or chemically captured in minerals. Bioenergy with CCS (BECCS) can be applied at biomass- fired power stations or any type of biorefinery. It is a particularly attractive option because the capture
and storage of biogenic CO2 effectively leads to removal of carbon from the atmosphere.
In most of the IPCC emissions scenarios that meet the 2-degree climate target, BECCS plays a large role as a negative emissions technology. This is crucial, given the fact that the world may, at current emissions, exceed the carbon budget for the 1.5-degree target already in 2021 and the 2-degree target in 203620. Negative emissions could not only help reduce overall emissions, but also remedy the likely overshoot of ‘allowable’ emissions associated with temperature targets.
BECCS technology plays a significant role in the IEA’s 2°C Scenario (2DS)21, and even more so in IEA’s more ambitious Beyond 2°C Scenario (B2DS)22. Annual negative emissions obtained through BECCS in
the 2DS reach 2.7 billion kg CO2e by 2060. BECCS specifically from biofuels production makes up more
than 60% of the 2.7 billion kg CO2e attributed to BECCS in the IEA 2DS.
The particular synergy between biorefining and CCS is due to the high-concentration stream of CO2 emitted from biorefinery fermentation processes. This significantly reduces the cost of CCS (Global CCS
Institute 2010). In fact, the costs per unit of CO2 avoided through CCS at a bioethanol plant may be 70% lower than through CCS at a coal-fired power plant (Global CCS Institute 2017).
One concern related to CCS is the potential leakage of CO2 from underground reservoirs. While this is a valid concern, small leakages do not undermine the overall benefit of the technology. According to NREL
(2011), only about one percent of stored CO2 is expected to leak over a period of 100 years.
20 https://www.carbonbrief.org/analysis-four-years-left-one-point-five-carbon-budget 21 According to the IEA: ”The 2DS describes an energy system consistent with an emissions trajectory that recent climate science research indicates would give an 80% chance of limiting average global temperature increase to 2°C.” 22 According to the IEA: ”The B2DS looks at how far known clean energy technologies could go if pushed to their practical limits, in line with countries’ more ambitious aspirations in the Paris Agreement.” 16 Bridging the gap to a sustainable future
Grid
Jet fuel
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Green electricity system
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Natural gas Coal Oil A biorefining vision Carbon storage 18 Bridging the gap to a sustainable future
4. Sustainable use of bio- feedstock within global limits
The limitations of sustainable production and sourcing of bio-feedstock is a key premise for its use in the envisioned green energy matrix. According to the IEA, the current total primary energy supply from bio-feedstock is approximately 53 EJ/y (IEA 2017b). More than half of this (28 EJ/y) is traditional (unsustainable) use23. Multiple studies agree that the sustainable primary bio-feedstock potential (using a food/fiber first principle) will be more than 100 EJ/y by 2050 (Creutzig et al. 2015). In their bioenergy roadmap, the IEA (2017b) assumes that 145 EJ of sustainable bio-feedstock will be available annually by 2060 (including 17 EJ for traditional use) 24. This shows that the full amount of sustainable bio-feedstock has not yet been utilized. It is a task in itself to ensure the mobilization of the remaining sustainable bio- feedstock potential to achieve climate targets of less than 2⁰C temperature increase.
The main categories of sustainable bio-feedstock that contribute to the IEA’s estimated supply of 145 EJ are:
1. Agriculture, including crops and fast-growing grasses and trees25 (42-46%) 2. Agricultural wastes and residues26 (35-40%) 3. Wood-harvesting residues (11-13%) 4. Municipal and industrial wastes (6-8%).
23 Traditional use primarily refers to inefficient use of biomass in open fires or basic stoves with low efficiency and high emissions of particulate matter and other air pollutants (IEA, 2017b) 24 This assumption aligns well with a number of other global studies (IEA 2017b, page 58) 25 ‘Produced on land in ways which do not threaten food availability and whose use leads to low land use change emissions, and subject to a positive assessment on other sustainability indicators such as biodiversity and water availability and quality’ (IEA 2017b, Table 8) 26 ‘Respecting the need to reserve some of the available resource for animal feed and to leave sufficient residues in the field for soil protection’ (IEA 2017b, Table 8) Bridging the gap to a sustainable future 19
There are intuitive concerns about food security when estimating sustainable bio-feedstock resources, particularly with respect to dedicated production of oil and starch crops for biofuels. These concerns are due to the common perception of a causal link between agricultural land occupation (for dedicated feedstock production) and global hunger. But, as mentioned by the expert Margaret Mellon from the Union of Concerned Scientists27, ‘there is no direct connection between U.S. corn and soy production and ending hunger elsewhere’. This was echoed in more general terms in the SCOPE report on bioenergy and sustainability (Souza et al. 2015) authored by roughly 130 scientists from around the world, stating that ‘There is no inherent causal relation between bioenergy production and food insecurity’.
It is often overlooked that bioenergy and biofuels can actually improve food security. Simplistic global analyses, headlines, and cartoons have obscured the main drivers of local food insecurity and ignored opportunities for bioenergy to contribute to solutions (Kline et al. 2016). The number one reason for hunger is poverty28, and more than 70% of the poor in developing countries live in rural areas29. For these people, bioenergy constitutes an opportunity for economic growth and employment. As stated by Heiner Thofern, Head of the FAO Bioenergy and Food Security Project: ‘Done properly and when appropriate, bioenergy development offers a chance to drive investment and jobs into areas that are literally starving for them’. Or as stated by José Graziano da Silva, Director-General of the FAO: ‘Given the right conditions, biofuels can be an effective means to increase food security by providing poor farmers with a sustainable and affordable energy source’.
Besides poverty, drivers of hunger include lack of investment in agriculture, climate and weather, war and displacement, unstable markets, and food waste28. For some of these, bioenergy also has a potential positive role to play (e.g., agricultural investments, mitigation of climate change, and diversification of farmers’ revenue streams to stabilize markets).
27 https://blog.ucsusa.org/margaret-mellon/lets-drop-feed-the-world-a-plea-to-move-beyond-an-unhelpful-phrase-229 28 https://www.wfp.org/stories/what-causes-hunger 29 http://www.fao.org/news/story/en/item/130449/icode/ 20 Bridging the gap to a sustainable future
5. Biorefining’s current and potential future contributions
This section takes a deeper look at climate change mitigation from existing enzyme-based biorefineries, as well as the future potential. This is based on projections of the ethanol volumes needed to limit global temperature increase to maximum two degrees Celsius by the end of the century30. The projections stem from the IEA 2DS as laid out in the bioenergy roadmap by the IEA (2017b). The 2DS relies on a number of complementary technologies, including heavy penetration of electric vehicles (cf. ‘IEA 2DS’ in Fig. 2). Additional details are available in Appendix E: The IEA 2-degree scenario (2DS).
In general, biorefining of sustainable sugar, starch, and cellulosic feedstocks should collectively supply 290 billion liters of ethanol by 2060 (IEA 2017b). As described in the sections below, this ethanol
production, in combination with CCS, may simultaneously enable the removal of 240 million Mg of CO2 31 from the atmosphere (9% of total CO2 removal in the IEA 2DS).
5.1 Current contribution from biorefineries using sugar- and starch-crops
Current global biofuel production is dominated by ethanol produced from sugar- and starch-crops. In 2014, global production of sugar- and starch-based ethanol was 2.1 EJ or 100 billion liters (IEA 2017b). Almost 60% of the ethanol was produced in the USA, primarily from corn, and another 25% was produced in Brazil, primarily from sugarcane32. Europe accounted for 6%, produced from corn, cereals, and sugar beet. China and Canada also produced significant amounts. Fig. 5 gives a rough overview of current ethanol production (primarily sugar- and starch-based) and planned expansion (including cellulosic ethanol).
+50
60
+3 4 +20
+25 +0,5 3 1
30
Fig. 5: Current ethanol production (dark bars) and planned future expansion (green bars). Unit: billion liters
30 Note that only ethanol for direct use is considered here. Any ethanol used as an intermediate in biojet production or production of other biofuels is not considered 31 This is net removal, also taking other life cycle emissions into account 32 Based on data from the Alternative Fuels Datacenter, https://www.afdc.energy.gov/data/ Bridging the gap to a sustainable future 21
5.1.1 Current climate-change mitigation from sugar- and starch-based biorefineries Differing estimates of life-cycle GHG emissions exist due to differences in methodologies, assumptions, etc. Table 1 shows the data that has been applied in the present report to obtain a rough estimate of the GHG-savings from today’s production of bioethanol.
TABLE 1: Applied assumptions regarding life cycle GHG emissions from current ethanol production
GHG saving versus... Country Dominant Life cycle Comments or region feedstock GHG emissions average marginal gasolinea gasolineb
USA Corn 62 g CO2e/MJ 34% 46% ILUC included (Wang et al. 2012)
Brazil Sugarcane 45 g CO2e/MJ 52% 61% ILUC included (Wang et al. 2012)
Europe Corn, wheat, sugar beet 46 g CO2e/MJ 51% 60% ILUC included (see Appendix F)
China Corn 62 g CO2e/MJ 34% 46% Assumed to be same as USA
Canada Cereals 46 g CO2e/MJ 51% 60% Assumed to be same as Europe
Rest of world Mixed incl. molasses 46 g CO2e/MJ 51% 60% Assumed to be same as Europe
a Life cycle GHG emissions: 94 g CO2e/MJ (Wang et al. 2012) b Life cycle GHG emissions: 115 g CO2e/MJ (Ecofys 2014)
Based on the life-cycle GHG data in Table 1 and global production volumes33, the total emissions from
current ethanol production amount to 110 million Mg CO2e. These emissions incorporate indirect land use change emissions, i.e. emissions from the margin of the agricultural land base (assumed to be impacted by ethanol production from starch and sugar crops). To be methodologically consistent, it is equally important to focus on the margin of the crude oil system when considering the fossil fuel production displaced by ethanol. Ecofys (2014) studied the impacts of marginal crude oil production
and found that a relevant estimate of emissions from marginal fossil fuel production was 115 g CO2e/ MJ. On this basis, the displaced fossil fuel emissions from sugar- and starch-based ethanol production
in 2014 amounted to 227 million Mg CO2e (assuming direct displacement based on energy content). In
other words, global sugar- and starch-based ethanol production avoided roughly 120 million Mg CO2e. This is equivalent to the tailpipe emissions of 25 million US cars with conventional internal combustion engines34.
Moreover, starch-based ethanol refineries produce more than liquid fuel. They also produce protein- rich animal feed for the livestock sector. For every kg of corn going into a biorefinery, approximately 0.3 kg (dry matter) comes out in the form of so-called dried distillers grains with solubles (DDGS). This is used in feed for cattle, chicken, and other livestock and is accounted for in the life-cycle GHG emissions mentioned in Table 1. But this aspect is often absent in the general discussion about biorefining of corn and cereals (sometimes causing misleading statements about the land use associated with ethanol production).
33 Data for 2014: https://www.afdc.energy.gov/data/ 34 Based on emissions data from the US EPA: https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-typical-passen- ger-vehicle 22 Bridging the gap to a sustainable future
5.1.2 Future climate-change mitigation from sugar- and starch-based biorefineries
As heat, power, and transport emissions will generally decrease with the adoption of greener technologies, the carbon footprint of sugar- and starch-based ethanol will also decrease (Brown 2018).
In addition, the capture and storage of CO2 from ethanol fermentation allows for even further reduction
of the ethanol footprint. Already today, US corn ethanol producer ADM is capturing and storing CO2 in an underground reservoir35.
By 2060, the IEA (2017b) foresees a need for 2.7 EJ (~130 billion liters) from sugar- and starch-based ethanol to stay on track with the 2-degree target. This is an increase of roughly 30% compared to 2014. To consider the GHG emissions of this future contribution to the renewable energy matrix, we’ve made the following assumptions:
• The increase in sugar- and starch-based ethanol comes primarily from sugarcane production (based on IEA (2017b)) • Cleaner energy (electricity and fuels) reduces the carbon footprint of sugar- and starch-based ethanol by 30% (before application of CCS in fermentation) • CCS is applied to all ethanol fermentation and hence the carbon footprint of all sugar- and starch-
based ethanol is (further) reduced by 21 g CO2e/MJ based on NREL (2011). For further info, see Appendix D (Section 11.3.1).
On this basis, 2.7 EJ of sugar- and starch-based ethanol could be produced with a carbon footprint of 41
million Mg CO2. In other words, sugar- and starch-based ethanol production could increase by 30% with a total reduction in emissions of more than 60%. Eventually, emissions from sugar- and starch-based ethanol could approach zero, assuming agricultural GHG emissions from feedstock production could be negated by CCS applied in fermentation (and zero-energy emissions). With precision agriculture and renewable sources of electricity to operate the plants, carbon emissions could even become negative for most plants.
35 https://bioenergyinternational.com/biofuels-oils/adm-starts-commercial-scale-ccs-decatur-ethanol-plant Bridging the gap to a sustainable future 23
5.2 Potential future contributions from cellulosic biorefineries
Cellulosic biofuel production has not been significant to date, but more than a handful of commercial- scale facilities have been constructed around the world, plus a similar number of demo plants and more than 40 pilot plants (IEA 2017b, p. 15 and p. 37).
This section describes how much enzyme-based cellulosic biorefineries could contribute if they were to provide the entire volume of cellulosic ethanol to be produced in the IEA 2DS by 2060, i.e. 3,400 PJ or 116 billion liters (cf. Appendix E). More specifically, the integrated biorefinery model in Fig. 3 is used to develop estimates of the total contributions that cellulosic biorefineries could provide, considering not just the liquid fuel but also the co-products. These contributions are then seen in relation to the bigger picture of the IEA 2DS projections. It is important to note that all calculations are meant solely to provide order-of-magnitude results.
The production of 116 billion liters will require 535 billion kg of dry bio-feedstock, which corresponds to roughly 7% of the sustainable bio-feedstock (145 EJ) in the IEA 2DS. This assumes an ethanol yield of 0.3 l/ kg of dry bio-feedstock36 (cf. Fig. 3), and a biomass energy content of 19.5 MJ per kilogram of dry biomass.
The excess combustibles from cellulosic ethanol production (primarily lignin) can be stored for use during seasonal peak electricity demand, generating a total of 144 TWh electricity37. Total electricity production in the IEA 2DS is 26.8 EJ or 7,400 TWh. Assuming 15% of this (1,100 TWh) needs to be available for seasonal peak demand (in the form of storable energy)38, cellulosic ethanol plants could supply 13% of this demand. In fact, they could potentially supply much more. If power consumption at the plant is covered by grid electricity (primarily based on intermittent renewables), more lignin would be available for peak demand periods. In addition, biogas from anaerobic digestion could (if not used for other purposes) be stored and used for electricity production during peak demand. Balancing the grid with side streams from cellulosic biorefineries could help reduce the use of natural gas, which is typically the preferred energy source to balance intermittent electricity generation from wind and solar (European Commission, 2016, p. 65-66).
The potential co-production of biomethane (upgraded biogas) would amount to 31 billion m3 or 1,180 PJ (assuming a biomethane energy content of 38.2 MJ/m3). This is more than 50% of the total biogas production in the IEA 2DS. This relatively high contribution is due to the fact that biogas is not one of the dominant energy sources in the IEA 2DS (8% of liquid and gaseous fuels by 2060, in terms of energy). Another reason is that the potential for co-production of biogas at a cellulosic ethanol factory is fairly substantial (cf. Fig. 3).
If CCS is used to capture carbon from ethanol fermentation, anaerobic digestion (of vinasse), and power
production from lignin, cellulosic ethanol emissions can be as low as -83 g CO2e/MJ (cf. Appendix D). This does not include CCS during potential combustion of co-produced biomethane (e.g., if used for
CHP). Moreover, the GHG emissions of -83 g CO2e/MJ is based on straw as feedstock, i.e., an agricultural residue. Other types of feedstock will be associated with either higher or lower GHG emissions. Under the (simplistic) assumption that total cellulosic ethanol production is derived from agricultural residues, the aggregate GHG mitigation potential from bio-feedstock processed in a cellulosic ethanol refinery with CCS
amounts to more than 280 million metric tons of CO2 equivalents (negative GHG emissions). This does not include any credits for displaced fossil fuel production. To put this abatement potential into perspective, it amounts to more than 10% of the total BECCS abatement in the IEA 2DS. The energy needs of CCS will reduce some of the co-produced electricity from lignin, but this has been taken into consideration in the estimate of life cycle GHG emissions where process emissions from CCS are accounted for.
36 Ethanol yields will vary depending on time perspective and technological setup. Wang et al. (2012) assumed higher etha- nol yields for cellulosic pathways (0.375 liters per kg dry feedstock) but a slightly lower output of excess electricity (and no production of biogas) compared to the data in Fig. 4. 37 Not taking potential energy needs for pelletizing (or similar treatment) into account 38 In their 2018 consultation paper on bioenergy and biobased products, the Energy Transitions Commission (ETC) assumed that 10-15% of the electricity supply needs to be available in the form of stored fuels to cover seasonal periods of peak electricity demand 24 Bridging the gap to a sustainable future
6. Conclusions
Climate change presents one of the greatest and most urgent challenges of our time. The broad vision that Novozymes offers in this report describes a pathway embracing a portfolio of integrated and commercially available green technologies. This pathway can be used to bring carbon emissions down, starting immediately.
Timely action will require the right policy incentives, stakeholder engagement, and broad coalitions between industry and government that share a united vision of green energy solutions. Today, companies, consumer groups and governments at many levels are discussing the ideal energy mix of the future. Naturally, each group is seeking to define what role they can play, what contribution they can make to the larger picture. This report is Novozymes’ contribution to this conversation. It is intended to inspire and set forth a vision of what is possible.
The report focuses on the pivotal role of sustainable biorefining in reducing GHG emissions. Biorefining technologies are proven and available today. They are particularly well suited to adapt to the quickly evolving and uncertain future of energy markets. The advantages of biorefining are its complementarity with other green energy sources, its compatibility with green vehicle technologies, and its scalability and versatility in inputs and outputs.
The biorefining platform, which can be described as building upon nature’s own intelligent carbon- capture technology, is also very well suited to low-cost CCS. CCS will likely be crucially important going forward, as almost all climate scenarios regard negative carbon emissions as essential to keep global temperature increase below 2 degrees Celsius.
A key challenge of biofuels has been the controversy around the sustainability of bio-feedstocks, particularly on the issues of land use change and food security. Novozymes takes these issues seriously and addresses them in this report. In short, we agree that the use of bio-feedstock must be carefully managed.
These and other factors are explored in this report, which is intended to start a conversation and help define an effective pathway for the international community to immediately address climate change. We owe this to our future, as we did not inherit this earth from our ancestors, but are borrowing it from our children. Let us set aside our differences and enter the energy revolution today.
This document is available at www.novozymes.com/bioenergy for all to access and use without restrictions. Bridging the gap to a sustainable future 25
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Appendix A: 8. Overview of biorefining technologies
The biorefining process converts biological materials to valuable products. The primary products from biorefineries are biogas, liquid biofuels, proteins, hydrocarbon feedstocks for biochemical and biomaterials, and combustibles (notably lignin) that can be stored and used for heat and power. There are many types of conversion technologies, which can be generally grouped into four different categories: 1) biochemical, 2) thermal, 3) thermochemical, 4) chemical.
8.1 Biochemical conversion technologies
The biochemical route for conversion of bio-feedstock includes both anaerobic digestion and enzymatic release of sugars. Anaerobic digestion is used for production of biogas from bio-feedstocks such as manure and slaughterhouse waste. Vinasse/stillage from biorefineries can also be used as feedstock, and the resulting biogas can be used as fuel for CHP or (in upgraded form) as fuel for some types of trucks and buses. The potential downside of biogas is methane losses to the atmospher e (fugitive emissions). Methane is a potent greenhouse gas and even small fugitive emissions can ruin the climate benefit. However, in the case of manure, which emits substantial amounts of greenhouse gases in the absence of further processing, the use of anaerobic digestion is an effective solution to eliminate such emissions and simultaneously create a useful fuel.
Enzymatic release of sugars allows for subsequent fermentation to ethanol and, with engineered yeasts, to isobutanol and other chemicals. Ethanol can either be used directly in blends with gasoline, or can be further processed (via dehydration, oligomerization, and hydrogenation) to more energy dense fuels. Sugars can also undergo catalytic reforming to produce fuels and chemicals. A process flow diagram of various routes to end products from sugars produced by enzymatic hydrolysis is shown in Fig. 6. Side products of the biochemical process include proteins (e.g., animal feed) and lignin. Soluble lignin can potentially be mixed with ethanol to produce a marine fuel (Felby 2018).
Cellulose based Starch based Sugar based
Pretreatment Milling Crushing
Hydrolysis Liquefaction + saccharification*
Sugars
Fermentation Fermentation Catalytic reforming
Distillation Distillation/Separation Fractionation
Ethanol Higher alcohols Industrial chemicals
Dehydration + Oligomerization + Hydrogenation
Gasoline, diesel and jet fuel
*In the case of ethanol production from starch feedstock, the most common process is liquefaction followed by SSF (simultaneous saccharification and fermentation).
Fig. 6: Process flow diagram illustrating several routes to fuels and chemicals from sugars produced via enzyme-based conversion of bio-feedstock. 28 Bridging the gap to a sustainable future
8.2 Thermal conversion technologies
Examples of thermal conversion include combustion, pyrolysis, and torrefaction. Combustion is the burning of biomass in the presence of oxygen, and the output is typically steam, heat, and power. In a furnace, the heat from combustion can be distributed in the form of hot air or water. In a boiler, the heat of combustion is converted into steam, which can be used to drive turbines to produce electricity or can be used in district heating/cooling systems. Steam from a boiler contains roughly 60% of the biomass energy. Co-generation, or combined heat and power (CHP), recovers waste heat from power production for use in district heating, increasing the conversion efficiency to roughly 85% of the biomass energy.
Pyrolysis and torrefaction convert bio-feedstocks into gas, oil, or forms of charcoal. Pyrolysis of bio- feedstock is a partial combustion process that takes place at high temperatures (>430°C) and low oxygen levels. The output is liquid fuel that must be upgraded and a solid biochar residue similar to charcoal. Torrefaction takes place at lower temperatures and in the absence of oxygen, and the output is an energy dense solid fuel referred to as “bio-coal”.
8.3 Thermochemical conversion technologies
The term ‘thermochemical conversion’ is often used to encompass a broad range of technologies, including those listed above as thermal conversion technologies. Beyond those technologies, it refers most commonly to the process of bio-feedstock gasification to produce syngas (carbon monoxide and hydrogen), which is then converted to biofuels or biochemicals via Fischer-Tropsch39. It also refers to the hydrotreatment processing of tall oil feedstock, which is a by-product of the pulp and paper industry, for the production of renewable biodiesel.
8.4 Chemical conversion technologies
Transesterification of fatty acids from oils, fats, and greases is the most common form of chemical conversion. Biodiesel is a common end product, along with glycerin and soaps.
39 Chemical reactions converting carbon monoxide (CO) and hydrogen (H2) into liquid hydrocarbons under high pressure, high temperature, and the presence of a metal catalyst Bridging the gap to a sustainable future 29
Appendix B: 9. Overview of transport technologies
9.1 Light duty vehicles (passenger cars)
• Internal combustion engines (ICE): An ICE vehicle is the most common passenger car today. It faces competition from EV technology but is likely to continue constituting a substantial share of the total vehicle fleet for decades to come. Even in aggressive projections of EV adoption, it is estimated that there will still be more than 1 billion ICE passenger cars on the roads (globally) in 2040.
• Electric vehicles (EV): Electric vehicles have an electric motor and run on batteries. In 2017, there were more than 2 million EVs on the roads (globally). Estimates of their further penetration of the market for passenger vehicles vary widely but aggressive projections suggest that there will be more than 500 million EVs (incl. hybrids) on the roads by 2040 constituting roughly one-third of the global light duty vehicle fleet.
• Hybrids (incl. plug-in): Hybrid vehicles have both an ICE and an electric motor. Plug-in hybrids allow for an external electricity source to charge the battery. According to BNEF (2017), hybrids will play a significant role in the coming years whereas pure EVs still suffer from limited driving range.
• Fuel cell vehicles (FCVs): In a fuel cell, hydrogen reacts with oxygen to form water. The reaction produces electricity, which can then power an electric motor (to run a car). The oxygen typically comes from air whereas the hydrogen can be provided in multiple ways. One way is storage of pure hydrogen (H2) in a tank on board the FCV. However, the on-board storage of hydrogen presents a risk of explosion, and a viable alternative to avoid this risk is the storage of ethanol (C2H5OH), which can supply hydrogen to the fuel cell via an on-board converter40.
• Flexible fuel vehicle (FFV): A FFV is designed to run on more than one fuel. FFVs can be fueled with unleaded gasoline blended with either ethanol or methanol fuel, in any combination ranging from pure gasoline to pure alcohol. As the FFV can automatically prompt adjustments for fuel composition, all fuels are stored in the same tank. This technology ensures that standard performance areas such as power and acceleration are not significantly affected41.
• Hybrid flex-fuel vehicle (HFFV): A HFFV is, as the name implies, a combination of FFV and the
hybrid system. The HFFV has the potential to considerably reduce the total CO2 emissions, given the efficiency of the hybrid system and low carbon emissions of ethanol. A new model was presented in March 2018, and a launch is currently planned for Brazil. Until then, more data will be collected through real-world testing to evaluate the system’s durability, reliability and performance42.
Appendix C-D discuss life cycle GHG emissions from light duty vehicles with and without the use of CCS in electricity and biofuels production.
40 https://fuelcellsworks.com/news/nissan-completes-first-phase-of-testing-on-its-bio-ethanol-fuel-cell-vehicle-in-brazil 41 https://www.afdc.energy.gov/pdfs/41597.pdf 42 https://newsroom.toyota.co.jp/en/corporate/21633112.html 30 Bridging the gap to a sustainable future
9.2 Heavy duty vehicles (HDVs)
• Internal combustion diesel engine: The ICE diesel engine is by far the most common type of drive train for HDVs, and the replacement of fossil diesel with sustainable biodiesel would have considerable impact on reducing carbon intensity.
• Internal combustion ED95-adapted engine: ED95 is an ethanol based fuel for adapted diesel engines, where 95% of the fuel is ethanol, and the remaining 5% consists of ignition improver, lubricant, and corrosion protection43. ED95 is as effective as diesel for heavy goods transport and has been implemented in more 700 ethanol buses across Sweden44. The adapted diesel engine has the advantage of increasing the utilization of ethanol by up to 40% compared to a petrol engine. Additional benefits include reduction in emissions of hazardous particles and reduction in carbon emissions by up to 90% compared to diesel45.
• Electric truck: Whereas electrification is an increasing trend for light duty vehicles, electrification is more challenging for heavy duty vehicles due to range issues, charging challenges, and the weight/ volume of the batteries required for long distances and heavy loads. Even so, electrification may have a role to play in the decarbonization of HDVs46 along with gaseous and liquid biofuels as well as fuel cells. According to BNEF, over the next two decades the world’s city buses will rapidly convert from diesel to battery-powered technologies. City buses have unique characteristics that make them less difficult to electrify. They usually travel reliable, predictable routes and return to a centralized deport where they can recharge. Additionally, they don’t carry a too heavy load, compared to vehicles such as long-haul trucks.
• Fuel cell truck: See description of fuel cell vehicle in previous section for light-duty vehicles.
• Natural gas vehicle: Some trucks and buses can be fueled by natural gas, or essentially methane, which can be sourced from biological feedstock (e.g., upgraded biogas).
9.3 Aviation
Aviation will also be hard to electrify and consequently liquid jet fuel will likely be required for many decades to come. If fossil fuels are to be phased out, liquid fuels from bio-feedstock are one of the few realistic alternatives. Already today, there are technologies that can produce bio-based jet fuel. Just as sugars can be fermented to ethanol, they can also be fermented to iso-butanol47 or farnesene48, which can be further refined into jet fuel substitutes. Other technologies for conversion of bio-based sugars49 and alcohols50 to jet fuel are moving into demonstration scale.
According to Han et al. (2017), various sugar-to-jet and ethanol-to-jet pathways can reduce GHG emissions in a near-term scenario. Most notably, corn stover-based jet can be produced with GHG 51 emissions as low as 12-17 g CO2e/MJ (without including CCS). This is a reduction of 80-87% compared
to average fossil-based jet fuel (85 g CO2e/MJ).
43 http://www.sekab.com/biofuel/ed95-for-sustainable-transport/ 44 http://www.greencarcongress.com/2010/06/scaniabus-20100621.html 45 http://www.sekab.com/biofuel/ed95/ 46 https://www.sei-international.org/mediamanager/documents/Publications/SEI-2017-FS-Nykvist-Decarbonize-Road-Freight.pdf 47 http://www.gevo.com/our-markets/jet-fuel/ 48 http://www.greenaironline.com/news.php?viewStory=1937 49 http://www.global-bioenergies.com/global-bioenergies-joins-aireg-to-push-the-jet-fuel-application-of-its-isobutene-pro- cess/?lang=en 50 http://www.biofuelsdigest.com/bdigest/2017/08/22/vertibirds-are-go-doe-oks-vertimass-drop-in-biofuels-technology- clears-path-to-demo-scale/ 51 This result is based on a displacement (or system expansion) approach where excess electricity from the biorefinery replaces electricity on the grid (average US mix assumed) Bridging the gap to a sustainable future 31
9.4 Rail
Passenger and freight transport by rail can be shifted to electricity, which will be an advantage as the electricity grid gradually becomes greener. Many railroads have already been electrified and ‘The Community of European Railway and Infrastructure Companies’ (CER) has made a pledge to strive for carbon-free train operation by 2050 (CER and UIC 2015). Meanwhile, there are still many trains running on fossil fuels.
9.5 Marine
Maritime transport is responsible for 4-9% of global SOx emissions and 10-15% of global NOx emissions (IEA Bioenergy, 2017). In the next few years, the sector is expected to undergo major changes due to tightened regulation measures of fuel sulfur levels by the International Marine Organization. Many solutions are being explored to achieve reductions in both sulfur and carbon emissions. Alternative non-fossil fuels include bio-diesel, bio-methane, ammonia, bio-methanol, and lignin ethanol oil. The EU Joint Research Centre has looked at a range of these and identified bio-methane and bio-methanol as promising options52, and the IEA has identified HVO, drop-in biodiesel and potentially bioethanol (with multifuel engines) as ideal alternatives53.
52 https://ec.europa.eu/jrc/en/news/shipping-sector-emissions-alternative-fuels-marine-and-inland-waterways-transport 53 https://www.ieabioenergy.com/wp-content/uploads/2018/02/Marine-biofuel-report-final-Oct-2017.pdf 32 Bridging the gap to a sustainable future
Appendix C: 10. Life cycle GHG emissions from light duty vehicles (without CCS)
This appendix discusses near-term life cycle GHG emissions from light duty vehicles with no assumptions about CCS being used in electricity and/or biorefining.
10.1 Life cycle GHG emissions from transportation fuels (well-to-wheel)
First, ranges in GHG emissions from different fuels are explored. These are depicted in the following figure and discussed in the text beneath.
300
250
200
150 e/km 2 100 g CO 50
0
-50
-100 Gasoline Electricity Biothanol (incl. ILUC)
Fig. 7: Life cycle GHG emissions from transportation fuels (without CCS)
Note that the emissions from the production and use of the fuels have been expressed in g CO2 equivalents per km driven. This is to enable a comparison between electricity (for EVs) and liquid fuels (for ICEs).
Assumptions for fuel consumption are as follows: • ICE fuel consumption: 181 MJ/100 km (derived from PE Int’l 2013) • (B)EV fuel consumption: 15 kWh/100 km (PE Int’l 2013, page 14) Bridging the gap to a sustainable future 33
The upper and lower ranges of the emission ranges in the figure above are discussed in the following.
Gasoline
54 • Lower bound: The EU fossil fuel comparator of 83.8 g CO2e/MJ (EC 2009) 55 • Upper bound: US oil shale (139 g CO2e/MJ) based on ERA (2009)
Electricity
• Lower bound: Wind-based electricity (4 g CO2e/kWh) based on ecoinvent 2 (LCA database)
• Upper bound: Coal-based electricity (1.02 kg CO2e/kWh) based on Muñoz et al. (2015)
Bioethanol
56 • Lower bound: Corn stover ethanol (-27 g CO2e/MJ) based on US EPA (2010) 57 • Upper bound: Corn ethanol (73.5 g CO2e/MJ) based on US EPA (2010)
In relation to the lower bound for bioethanol, examples of other results are shown in Table 2.
TABLE 2: Examples of emissions from cellulosic ethanol
Feedstock Excess co-produced GHG emissions Source power displacing…
Corn stover Avg. US grid mix -27 g CO2e/MJ US EPA (2010)
Cereal straw Avg. DK grid mix -14 g CO2e/MJ Kløverpris et al. (2016a) Miscanthus
- Emissions excl. ILUC Avg. DK grid mix -12 g CO2e/MJ Kløverpris et al. (2016b)
- Indirect land use change (Not applicable) -12 g CO2e/MJ Globium (Valin et al., 2015)
- Total Avg. DK grid mix -24 g CO2e/MJ
54 Update to around 94 expected in the second version of the European Renewable Energy Directive
55 Gas-to-liquid (GTL) and coal-to-liquid (CTL) exceed 200 g CO2e/MJ (based on ERA 2009) and have not been included in the range shown 56 The negative emissions occur due to a large ’GHG credit’ for co-produced bioelectricity (displacing electricity on the grid) 57 Breakdown of results available in Appendix B 34 Bridging the gap to a sustainable future
10.2 Total life cycle GHG emissions from passenger vehicles (without CCS)
The life cycle GHG emissions of transportation fuels (well to wheel) is not the only parameter determining the total life cycle GHG emissions from driving. The following graph considers the major life cycle stages of selected light duty vehicles. The left side of the graph illustrates an ICE vehicle running purely on fossil fuels and the right side illustrates vehicles running entirely on renewable energy both as EV or ICE. The graph thereby illustrates extreme cases to show the difference between worst case and best case. Currently, no ICE vehicle runs on pure ethanol and no grid can provide pure wind power for an EV. However, the graph illustrates the perspectives of the different solutions, including what can be done today, tomorrow and in the future.
Time
40 38 35 34 End of life 30 Operation
25 Manufacturing
20 19 19
15
10 9
5
0
-5
-10 -3 Gasoline E15 Blend E85 Blend EV (EU mix) EV (100% BioEtOH (Marginal) renewable) with CCS
Fig. 8: Life cycle GHG emissions from light-duty vehicles including manufacturing and end-of-life. CCS is not applied for “E15 Blend”, “E85 Blend”, and “EV (EU mix)”. Assumptions include: 1) ethanol is 50% starch-based, 50% cellulosic; 2) GHG emissions of ICE vehicles are based on marginal gasoline; 3) vehicle lifetime of 150,000 km.
The graph shows the total life cycle GHG emissions including manufacturing, operation and end of life emissions. It has been assumed that a vehicle runs 150,000 km during its life time. Fuel use assumptions are the same as stated above, where the ethanol consist of a 50/50 % split between starch-based and cellulosic ethanol. Additionally, the emission numbers for production of electricity is based on Muñoz et al. (2015) and the operation of gasoline and different kinds of ethanol on Ecofys (2014) and Wang et al. (2012) respectively.
• Gasoline (marginal): GHG emissions from an ICE vehicle running on pure gasoline • E15 Blend: GHG emissions from an ICE vehicle running on 15 % ethanol and 85 % gasoline • E85 Blend: GHG emissions from an ICE vehicle running on 85 % ethanol and 15 % gasoline • EV (100% coal): GHG emissions from an EV (Nissan Leaf) running entirely on coal-based electricity • EV (EU mix): GHG emissions from an EV (Nissan leaf) running average EU mix of electricity • EV (100% wind): GHG emissions from an EV (Nissan Leaf) running entirely on wind-based electricity • Bioethanol (100%): GHG emissions from an ICE vehicle running on 50% starch-based ethanol and 50% cellulosic ethanol Bridging the gap to a sustainable future 35
Appendix D: 11. Life cycle GHG emissions from light duty vehicles (with CCS)
The present chapter discusses GHG emissions from biofuels and electricity production when CCS is applied. As for biofuels production combined with CCS, there is currently little information available in the literature. Hence, it has been necessary to combine several sources of information to develop estimates of GHG emissions from biofuels with CCS. This analysis is described as part of the present appendix and estimated GHG emissions from different fuels with CCS have been summarized in the graph below. Note that the appendix does not consider electricity production from primary bio- feedstock. This is because the limits on sustainable bio-feedstock prohibits the long-term use of primary bio-feedstock for power because it needs to be used elsewhere to meet international climate targets.
300
225
150
e/km 75 2
g CO 0
-75
-150
-225 Gasoline Electricity Biothanol (incl. ILUC)
Fig. 9: Life cycle GHG emissions from transportation fuels (with CCS)
Assumption about fuel consumption are the same as in Appendix A. Further details are outlined below.
Gasoline • Lower bound: CCS not considered relevant (no change compared to Appendix A) • Upper bound: CCS not considered relevant (no change compared to Appendix A)
Electricity • Lower bound: Wind-based electricity (no change compared to Appendix A)
• Upper bound: Coal-based electricity with CCS (203 kg CO2e/MWh) based on Cuéllar-Franca and Azapagic (2015), further discussion available in next section.
Bioethanol
• Lower bound: Straw-based ethanol with CCS (-84 g CO2e/MJ) based on modification of results in Kløverpris et al. (2016a), see discussion in subsequent section (‘Cellulosic ethanol with CCS’)
• Upper bound: Corn ethanol with CCS (31 g CO2e/MJ) based on modification of results in US EPA (2010), see discussion in subsequent section (‘Starch-based ethanol with CCS’) 36 Bridging the gap to a sustainable future
Co-products from biorefining handled via system expansion (displacement approach): Protein feed (DGS) from starch-based ethanol assumed to replace feed production elsewhere, upgraded biogas from cellulosic ethanol production assumed to replace natural gas, and excess bioelectricity from cellulosic ethanol production (conservatively) assumed to replace renewable energy (mainly wind) on the grid58.
11.1 Coal-based electricity production with CCS
In a review of CCS technologies, Cuéllar-Franca and Azapagic (2015) identified ‘pulverized coal’ power plants with post-conversion carbon capture via MEA (monoethanolamine) as the highest emitting fossil- based type of electricity production with CCS. The average life cycle GHG emissions for this technology
was 203 kg CO2e/MWh. Based on this number, the upper bound for GHG emissions related to distance
driven in an EV would be 30 g CO2e/km (assuming 15 kWh/100 km). This number has been used as the upper bound for electricity emissions in the previous graph (showing life cycle GHG emissions from transportation fuels).
For the analysis of total life cycle vehicle emissions with CCS (incl. manufacturing and ‘end of life’), a point estimate of GHG emissions from coal-based electricity was needed (cf. Fig. 10). For this purpose, it has been assumed that CCS can reduce net life cycle GHG emissions from fossil-based electricity production by roughly 73%. This is in line with estimates and ranges shown in the scientific literature (Branco et al. 2013, Cuéllar-Franca and Azapagic 2015, Lacy et al. 2015, Singh et al. 2011a, Singh et al. 2011b).
11.2 Cellulosic ethanol with CCS
The results in this section are based on an LCA of straw-based ethanol (Kløverpris et al. 2016a), which has been modified to indicate a lower bound for life cycle GHG emissions from cellulosic ethanol with CCS. The modification has been described in detail in this section.
The average (unmodified) base case results of the LCA by Kløverpris et al. (2016a) are shown in Table 3 below.
TABLE 3:
Average GHG emissions (g CO2e/MJ) from straw-based ethanol (base case in Kløverpris et al. 2016a)
Field Additional Transport of Biorefinery Avoided natural Avoided Other Total emissions field work straw auxiliaries gas electricity
9.6 1.4 2.2 12.9 -19.5 -1.9 -0.3 4.4
The results above are modified on three accounts to consider potential implementation of CCS.
1. Fermentation: It is assumed that CO2 from the fermentation process is captured and stored
2. Anaerobic digestion: It is assumed that CO2 from biogas production is captured and stored (and the credit for avoided natural gas is omitted)
3. CHP from lignin combustion: It is assumed that CO2 from lignin combustion (in combined heat and power production) is captured and stored (and the credit for avoided electricity is omitted)
58 In the (modified) US EPA analysis of starch-based ethanol (upper bound in the ethanol range), electricity is assumed to be the average US grid mix (US EPA 2010, page 332) Bridging the gap to a sustainable future 37
11.2.1 CCS in fermentation (impact on cellulosic ethanol)
It is estimated that the capture and storage of CO2 from fermentation in cellulosic ethanol production
could provide negative GHG emissions of roughly 22 g CO2e/MJ. The estimation is explained below.
Ethanol weighs 37 g/MJ and releases 71 g CO2/MJ at combustion (based on stoichiometry). This represents 25% of the C in the feedstock (EBTP ZEP 2012, Fig. 4). Another 13% of the feedstock C is
released as fermentation exhaust, i.e. 37 g CO2/MJ [13%/25% · 71 g CO2/MJ]. It is assumed that 90% of
the fermentation CO2 is captured, yielding a ‘gross’ CCS credit of 33 g CO2/MJ [90% · 37 g CO2/MJ]. In
addition, it assumed that compression and transport results in GHG emissions of 11 g CO2/MJ and that
1% of stored CO2 will escape to the atmosphere (both based on NREL 2011). This results in a net CCS
credit for fermentation of 22 g CO2/MJ.
11.2.2 CCS in anaerobic digestion (impact on cellulosic ethanol)
The straw-based biorefinery described by Kløverpris et al. (2016a) is using anaerobic digestion to
produce biogas from the vinasse (side stream). It is estimated that the capture and storage of CO2 from anaerobic digestion in an integrated cellulosic biorefinery could provide negative GHG emissions of
roughly 8.9 g CO2e/MJ. The estimation is explained below.
The biorefinery produces 194 3m methane (in the form of upgraded biogas) per m3 ethanol (derived from
Kløverpris et al. 2016a). Roughly 45% of the biogas (before upgrade) is CO2 (derived from Kløverpris et al. 3 3 2016a), which then translates to 160 m CO2 (from AD) per m ethanol or 320 g CO2 per liter ethanol (based 59 on a CO2 density of 2.0 g/l ). Assuming 90% capture of CO2, 1% leakage from CO2 storage (based on NREL 2011), and a 33% ‘GHG penalty‘ for compression and transport (based on NREL 2011), the net CCS credit
is 8.9 g CO2e/MJ [320 g CO2/l / 21.2 MJ/l ∙ 90% ∙ (1-33%) - 320 g CO2/l / 21.2 MJ/l ∙ 1%].
11.2.3 CCS in lignin combustion (impact on cellulosic ethanol)
The straw-based biorefinery described by Kløverpris et al. (2016a) is generating 1.2 kg lignin per liter of ethanol produced (56.7 g C/MJ). The lignin is burned to produce heat and power (CHP). It is estimated
that the capture and storage of CO2 from lignin combustion could provide negative GHG emissions of
roughly 78 g CO2e/MJ. The estimation is explained below.
The carbon content of lignin can vary from species to species. For this assessment, it has been assumed 60 to be 63.4% . On this basis, lignin combustion would generate 132 g CO2 per MJ ethanol [56.7 g C/MJ
∙ 63.4% ∙ 44/12 CO2/C]. Assuming 90% capture of CO2, 1% leakage from CO2 storage (based on NREL 2011), and a 33% ‘GHG penalty‘ for compression and transport (based on NREL 2011), the net CCS
credit is 78 g CO2e/MJ [132 g CO2/MJ ∙ 90% ∙ (1-33%) – 132 g CO2/MJ ∙ 1%].
59 http://www.uigi.com/CO2_conv.html 60 https://en.wikipedia.org/wiki/Lignin 38 Bridging the gap to a sustainable future
11.2.4 Summary of CCS in cellulosic ethanol
The estimated GHG impact of CCS in straw-based ethanol is outlined below.
TABLE 4: Average GHG emissions (g CO2e/MJ) from straw-based ethanol with CCS (modified from Kløverpris et al. 2016a)
Field Additional Transport of Biorefinery CCS CCS in lignin CCS in Other Total emissions field work straw auxiliaries in AD combustion fermentation
9.6 1.4 2.2 12.9 -8.9 -78.3 -21.9 -0.3 -83.4
As shown in Table 4, CCS in an integrated straw-based biorefinery could bring GHG emissions to -83 g
CO2e/MJ. This corresponds to -150 g CO2e/km, assuming a fuel efficiency of 181 MJ/100 km (derived from PE Int’l 2013).
11.3 Starch-based ethanol with CCS
The example here takes its point of departure in the biofuels LCA conducted by the US EPA (2010). According to the EPA analysis, corn ethanol from a new average natural gas-fired ethanol plant (63% dry DGS and 37% wet DGS, with fractionation) has a carbon footprint, which is 21% lower than the 61 average GHG emissions from US gasoline in 2005 . This corresponds to roughly 77,500 g CO2e/mmBTU
or 73.5 g CO2e/MJ. A breakdown of this result is shown in Fig. 2.6-2 in the report by the US EPA. Table 5 below shows the same (approximate) breakdown of emissions (based upon the previously mentioned figure in the EPA report). The following sections will explore how these emissions could be impacted by implementation of CCS in fermentation and energy production.
TABLE 5: GHG emissions from corn ethanol (based on US EPA 2010)
Life cycle stage g CO2e/mmBtu g CO2e/MJ Fuel production 28,300 26.9
International land use change 31,790 30.2
Int’l farm inputs and fertilizer N2O 6,350 6.0 Other (fuel and feedstock transport) 4,540 4.3
International livestock 3,460 3.3
International rice methane 2,380 2.3
Tailpipe emissions 650 0.6
Dom. farm inputs and fertilizer N2O 7,980 7.6 Domestic livestock -3,450 -3.3
Domestic rice methane -200 -0.2
Domestic land use change -4,300 -4.1
Total 77,500 73.5
61 Avg. US gasoline emissions in 2005: 98,205 g CO2e/mmBTU = 93.2 g CO2e/MJ (US EPA 2010, Section 2.5.8) Bridging the gap to a sustainable future 39
11.3.1 CCS in fermentation (impact on starch-based ethanol)
The assessment of CCS in fermentation is based on a report by NREL (2011). Figure ES-2 in the NREL report indicates that the difference in emissions between a corn ethanol pathway with and without CCS
(in fermentation) is 18 g CO2e/MJ. Meanwhile, this applies when the ethanol is blended with gasoline to 62 form an E85 fuel. An estimate for pure ethanol would thereby roughly 21 g CO2e/MJ .
11.3.2 CCS in electricity (impact on starch-based ethanol)
If CCS were applied in electricity production, it would impact several upstream emissions in the production of corn ethanol, incl. fuel production (energy for the ethanol plant) and production of fertilizers.
Fuel production: The production of starch-based ethanol requires energy in the form of heat and/or electricity. The energy production can take place either on-site or off-site. In the present analysis, it is assumed that the life cycle emissions from energy production in starch-based ethanol can be reduced via CCS by the same share as in electricity (see previous section), i.e. 73%.
Fertilizer production: Fertilizer production involves use of energy (electricity and natural gas). Hence, a reduction in electricity emissions (through use of CCS) would reduce fertilizer emissions. Nitrogen fertilizers have the highest energy and are therefore the focus of this assessment. In their LCA of corn ethanol, the US EPA (2010) estimated an increase in N fertilizer use of 1.32 kg N per mmBtu of corn ethanol63 or 1.25 g N/MJ. US EPA (2010) used emission factors from the GREET model developed by Argonne National Laboratory. Meanwhile, the US EPA does not state explicitly which factor they used. In the 2014 version of GREET, the life cycle GHG emissions from production of average nitrogen fertilizer
amount to 2.7 kg CO2e/kg N. Assuming this value is relevant for both the US and beyond, it corresponds
to 3.4 g CO2e/MJ or 25% of total farm inputs and fertilizer N2O (cf. table with breakdown of GHG
emission from corn ethanol above). To sanity check this value, an estimate of the N2O emissions from
N fertilizers is made: Assuming 1% of the increased use of N fertilizer (1.25 g N/MJ) is emitted as N2O
(standard IPCC assumption) and using an emission factor of 310 kg CO2e/kg N2O, the direct agricultural
N2O emissions (from artificial fertilizers alone) would amount to 3.9 g CO2e/MJ. With these numbers,
the emission from N fertilizer production (3.4 g CO2e/MJ) and the N2O emission from their use (3.9 g
CO2e/MJ) amount to 53% of the total emissions (domestic/US + int’l.) from the category ‘Farm inputs
and fertilizer N2O’ [6.0 g CO2e/MJ + 7.6 g CO2e/MJ = 13.6 g CO2e/MJ]. This indicate that the estimate of
emissions from N fertilizers is probably on the low side as N fertilizers (and associated N2O emissions) usually make up the lion’s share of fertilizer-related emissions in agricultural LCAs.
62 Estimate of CCS credit for corn ethanol (based on E85): 18 g CO2e/MJ / 0.85 = 21.2 g CO2e/MJ 63 This number is derived from Table 2.4-5 (change in domestic agricultural inputs) and Table 2.4-14 (international change in fertilizer and chemical use) in US EPA (2010) 40 Bridging the gap to a sustainable future
The question is now: How could emissions change if CCS were used? Ideally, this question would be answered based on a breakdown of the GHG emissions from average nitrogen fertilizer in GREET. As this was not readily available, a process from the ecoinvent database was used, namely liquid ammonia production in Europe, based on steam reforming64. Ammonia is the key ingredient in N fertilizers and steam reforming (of natural gas) is the predominate approach for ammonia production (Johnson et al. 2013). Hence, production data for ammonia (steam reforming of natural gas) is utilized to understand the GHG emissions from this process. Based on above-mentioned ecoinvent process, the production
of 1 kg liquid ammonia results in total life cycle GHG emissions of 1.96 kg CO2e of which 1.46 kg CO2
is emitted directly from the production process. Assuming 90% of this CO2 can be captured and stored
gives a gross CCS credit of 1.3 kg CO2e/kg ammonia. Assuming one-third of this is ‘lost’ to compression,
transport, and storage gives a net CCS credit of 0.88 kg CO2e/kg ammonia. This corresponds to a total reduction in life cycle GHG emissions of 45%. If this reduction could apply to N fertilizers in general,
the GHG emissions from N fertilizers (production) in the corn ethanol LCA would go from 3.4 g CO2e/MJ
ethanol (see estimate above) to 1.9 g CO2e/MJ ethanol, i.e. a reduction in the ethanol carbon footprint
of 1.5 g CO2e/MJ.
The analysis above is clearly uncertain because it has not been possible to piece consistent data together (reflecting the lack of research within this field). Never-the-less, the estimates are likely within the right order of magnitude and likely conservative as only CCS for direct emissions from N fertilizer production has been considered. CCS in electricity inputs has been disregarded and P and K fertilizers have not been considered. Besides, potential GHG reductions for transport and production of feedstocks (for fertilizers) have not been considered.
11.3.2 Summary of CCS in starch-based ethanol
The (conservatively) estimated GHG impact of CCS in starch-based ethanol has been outlined below.
Corn ethanol w/o CCS: 73.5 g CO2e/MJ
CCS, fermentation: - 21.2 g CO2e/MJ 65 CCS, direct energy : - 19.5 g CO2e/MJ
CCS, N fertilizer: - 1.5 g CO2e/MJ
Corn ethanol with CCS: 31.3 g CO2e/MJ
11.3.2 Total life cycle GHG emissions from passenger vehicles (with CCS in fuel production)
The following graph considers the major life cycle stages of selected light duty vehicles – assuming CCS is applied in production of bioethanol (as outlined above). Potential impact of CCS on manufacturing and ‘end of life’ (e.g. from bio-electricity with CCS) has not been considered.
64 Ammonia, liquid {RER}|ammonia production, steam reforming, liquid| Conseq, U (ecoinvent 3)
65 Based on fuel production emissions of 26.9 g CO2e/MJ (cf. table with GHG emissions from corn ethanol) and assumed emission reduction 73% (cf. section on CCS in electricity) Bridging the gap to a sustainable future 41
Time
40 38 35 End of life 30 31 Operation
25 Manufacturing
20
15 11 10 9
5 4
0
-5
-10 -3 Gasoline E15 Blend E85 Blend EV (EU mix) EV (100% BioEtOH (Marginal) renewable) with CCS
Fig. 10: Life cycle GHG emissions from light-duty vehicles including manufacturing and end-of-life. CCS is applied for “E15 Blend”, “E85 Blend”, and “EV (EU mix)”. Assumptions include: 1) ethanol is 50% starch-based, 50% cellulosic; 2) GHG emissions of ICE vehicles are based on marginal gasoline; 3) vehicle lifetime of 150,000 km.
Note, in the graph above, how the combined use of EVs and bioethanol can help drive down GHG emissions from light duty vehicles during the transition to a cleaner transport and energy system.
The assumptions applied in the figure above are the same as in the analysis without CCS, with the following exceptions.
• Cellulosic ethanol (point estimate): Straw-based ethanol with CCS (-83 g CO2e/MJ) based on modification of results in Kløverpris et al. (2016a) as discussed above
• Starch-based ethanol (point estimate): Based on the carbon footprint of corn ethanol (62 g CO2e/ MJ) by Wang et al. (2012) and the same CCS credits for energy and fermentation discussed previously
(respectively 19.5 and 21.2 g CO2e/MJ) • Electricity (point estimates): Based on JRC report (Edwards et al. 2014) 42 Bridging the gap to a sustainable future
Appendix E: 12. The IEA 2-degree scenario (2DS)
Broad consensus tells us that to reach international climate targets, we need not only a decoupling of economic growth from energy consumption but also a decoupling of energy demand from GHG emissions (Fig. 11; IEA, 2015). To achieve this goal, many energy analyses have published scenarios that identify the required contributions from various sectors with respect to energy demand. Our vision and analyses are based on these expert energy analyses, and in particular the IEA 2DS (2-degree scenario) (2017a).
20.000 Le axis : Primary energy demand
15.000 48 Right axis : Energy-related CO emissions
~6⁰ C
10.000 32 Gt
Mtoe ~4⁰ C
~2⁰ C 5.000 16
1990 2000 2010 2020 2030 2040
Fig. 11: Decoupling of energy demand and GHG emissions is needed to reach international climate targets (IEA 2015)
Overall, the IEA 2DS projects that the major contributors needed to bring emissions down from the IEA Reference Technology Scenario (RTS)66 levels to 2DS levels will be efficiency (40%), renewables (35%), CCS (14%), nuclear (6%), and fuel switching (5%). In the transportation sector, the IEA 2DS projects that end-use efficiency must be complemented primarily with a mix of renewable biofuels and electrification, all of which should be progressively phased in as they continue to mature and continue to decrease in carbon intensity (Fig. 12).
66 According to the IEA: ”The RTS provides a baseline scenario that takes into account existing energy- and climate-related commitments by countries, including Nationally Determined Contributions pledged under the Paris Agreement. The RTS is not consistent with achieving global climate mitigation objectives, but would still represent a significant shift from a historical ’business as usual’ approach.” Bridging the gap to a sustainable future 43
120 Hydrogen
Electricity
100 Biofuels
Other fossil
80 Jet fuel
Conventional diesel
EJ 60 Conventional gasoline
40
20
0 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 Fig. 12: Transport final energy demand in the IEA 2DS
The projected adoption of electrification in the 2DS is in line with the more aggressive forecasts (Fig. 2) and requires that the absolute number of light duty vehicles (LDVs) with internal combustion engines (ICE) continue to rise until the 2030s and fall to about half its current size by 2060 (IEA 2017a, Fig. 5.3). In the meantime, LDVs with electric powertrains (incl. hybrids) increases substantially and ultimately make up 77% of the total fleet by 2060 (IEA 2017a). Despite the aggressive forecast of electric vehicle adoption in the 2DS, there will continue to be roughly half a billion cars in the light duty segment by 2060 running on liquid fuels (IEA 2017a, Fig. 5.3).
For heavy-duty trucking, the 2DS requires a drastic reduction in solely ICE vehicles and a heavy penetration of hybrid and fully electric vehicles (IEA 2017a, Fig. 5.10), though with a longer timeline. This is similar but even more pronounced in the IEA’s below 2-degree scenario (B2DS). In aviation, the IEA 2DS involves many actions (including a significant shift to cellulosic biofuels), but electrification is not expected to play a significant role (IEA 2017a, p. 254). Nonetheless, there are ongoing initiatives to electrify short distance planes, for instance in Norway67.
The following sections discuss key elements of the IEA 2DS to set the stage for a deeper look at the role of ethanol biorefineries. Due to the integral nature of different technologies, the following sections do not only focus on biofuels but also on electrification, BECCS, and electro-fuels (as the interplay with these technologies impact the need for biofuels in the 2DS).
67 http://www.bbc.com/future/story/20180814-norways-plan-for-a-fleet-of-electric-planes 44 Bridging the gap to a sustainable future
12.1 Key elements of the IEA 2DS
12.1.1 Biofuels
By 2060 in the 2DS, final energy demand from transport biofuels reaches nearly 30 EJ (nearly 10 times 2016 levels), and provides 29% of total transport final energy demand. The contribution from each type of biofuel is as follows and as illustrated in Fig. 13:
• Biodiesel from oil crops is phased out completely by the year 2050. • Cellulosic biodiesel increases from nothing in 2017 to 11.5 EJ by 2050 and 14.5 EJ by 2060 (constituting almost half of total biofuel volumes). Biodiesel is mostly used in medium/heavy freight and shipping (Brown 2018) • Sugar- and starch-based bioethanol grows slightly compared to 2017 levels, after which it remains relatively constant at a level between 2.3 and 2.9 EJ until 2060. • Cellulosic bioethanol grows from negligible demand in 2017 to roughly 3.5 EJ in 2050 (3.4 EJ in 2060). • Biomethane grows from a very low level in 2017 and peaks in 2040 at 3.7 EJ, then falls to 3.0 EJ in 2050 (and 2.3 EJ in 2060). • Bio jet grows continuously from negligible demand in 2017 to no less than 5.4 EJ in 2050 (6.7 EJ in 2060), eventually constituting the second largest energy demand in the biofuels pool.
35 Biojet
Biodesel - cellulosic 30 Crop based FAME biodesel
Biomethane 25
Ethanol - cellulosic
20 Ethanol - sugar and starch EJ
15
10
5
0 2015 2025 2035 2045 2055
Fig. 13: Final transport energy demand by biofuel type in the IEA 2DS Bridging the gap to a sustainable future 45
12.1.2 Electricity production
Electricity production must double by 2060 with growth coming entirely from a combination of biomass (some with CCS) and other renewables (incl. wind and solar). Oil must be phased out completely and coal must be reduced drastically. Natural gas use decreases and nuclear and hydro increase. IEA (2017b) highlights the opportunities for grid stabilization and CCS/U with biomass in the electricity mix.
12.1.3 Bioenergy with carbon-capture and storage (BECCS)
BECCS plays an important role in the IEA 2DS and even more so in the B2DS. The annual negative
emissions obtained through BECCS in the 2DS increase to 2.7 billion kg CO2e by 2060. More than 60% of
these emissions are captured from concentrated CO2 streams from biofuels production, underlining the synergies between biorefining and BECCS.
12.1.4 Electro-fuels or synfuels from power-to-X processes
While electro-fuels hold potential as a supplement to other renewable fuels, they do not play a significant role in the IEA 2DS or B2DS, mainly due to ‘limited availability of low-cost electricity supply and the narrow geographical scope for renewables-based and very low-cost electricity over sufficiently long periods’ (IEA 2017a, p. 221). If the technology can be successfully demonstrated and costs can be reduced, electro-fuels may be able to supply 1.2-1.7% of EU transport fuels by 2030 (IEA 2017b, Box 4).
12.1.5 Key results from the IEA 2DS
The table below summarizes the required development in biofuels production and BECCS to stay on track with the 2-degree target according to the IEA 2DS (IEA 2017b).
TABLE 6: Biofuels use and BECCS in the two-degree scenario (2DS) by the International Energy Agency (IEA 2017b)
2014 2025 2030 2035 2040 2045 2050 2055 2060
Eth. from sugar/starch (PJ) 2,100 2,800 2,300 2,300 2,600 2,600 2,600 2,900 2,700
Cellulosic ethanol (PJ) 0 600 1,100 1,600 2,400 3,200 3,500 3,900 3,400
Biodiesel from oil crops (PJ) 900 1,100 800 600 300 100 0 0 0
Cellulosic biodiesel (PJ) 0 1,000 2,200 3,900 6,500 9,100 11,500 14,000 14,500
Biogas (PJ) 0 1,300 2,300 3,300 3,700 3,600 3,000 2,600 2,300
Bio jet (PJ) 0 300 1,000 2,100 3,300 4,600 5,400 6,000 6,700
BECCS* (bill. kg CO2) 0 100 200 400 600 950 1,300 2,000 2,700
* Based on Figure 14 in IEA (2017b) 46 Bridging the gap to a sustainable future
Appendix F: 13. Estimation of average life cycle emissions from European ethanol
This appendix explains the estimation of the life cycle GHG emissions for European ethanol listed in Table 1.
The average certified GHG savings of ethanol in Europe in 2017 were 70% compared to a fossil fuel 68 comparator of 83.8 g CO2e/MJ as stipulated in Europe’s Renewable Energy Directive . Hence, the
average GHG emissions from European ethanol in 2017 were (1-0.7) · 83.8 g CO2e/MJ = 25 g CO2e/ MJ. Meanwhile, this estimate does not consider potential indirect land use change (ILUC). To factor this in, ILUC factors from the Globium study (Valin et al. 2015) have been applied in combination with production volumes as presented by the European ethanol trade association (ePure). The information is available in Table 7.
TABLE 7: ILUC factors and ethanol feedstock split in Europe
Ethanol ILUC factorsb Ethanol splitc
feedstock (g CO2e/MJ) (2017)
Maize 14 39%
Wheat 34 30%
Sugar beet 15 20%
Othera 21 11%
a Average for maize, wheat, and sugar beet b Based on Globium (Valin et al., 2015) c https://epure.org/media/1763/180905-def-data-epure-statistics-2017-designed-version.pdf
Based on the data in Table 7, the weighted average ILUC factor for European ethanol is 21 g CO2e/MJ.
This number can be added to the estimated direct emissions (25 g CO2e/MJ), which gives the estimated
total emissions listed in Table 1 (46 g CO2e/MJ).
68 https://epure.org/media/1763/180905-def-data-epure-statistics-2017-designed-version.pdf Bridging the gap to a sustainable future 47 WAN E S CO IC L D A B R E O L
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