1、DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLESPERSPECTIVES FOR THE G7 IRENA 2024 Unless otherwise stated,material in this publication may be freely used,shared,copied,reproduced,printed and/or stored,provided that appropriate acknowledgement is given of IRENA as the source and copyright holder.

2、Material in this publication that is attributed to third parties may be subject to separate terms of use and restrictions,and appropriate permissions from these third parties may need to be secured before any use of such material.ISBN:978-92-9260-601-5Citation:IRENA(2024),Decarbonising hard-to-abate

3、 sectors with renewables:Perspectives for the G7,International Renewable Energy Agency,Abu Dhabi.Acknowledgements This report was authored by Gayathri Prakash,Carlos Ruiz,and Luis Janeiro,under the guidance of Francisco Boshell and Roland Roesch(Director,IRENA Innovation and Technology Centre),with

4、the support of the 2024 Italian G7 Presidency,to inform discussions during meetings among senior officials as well the G7 Ministers Meeting on Climate,Energy and Environment in Torino City on 29-30 April 2024.Valuable input was also provided by IRENA colleagues:Simon Benmarraze,Emanuele Bianco,Yong

5、Chen,Abdullah Fahad,Jinlei Feng,Ricardo Gorini,Nolwazi Khumalo,Daniel Russo,Zafar Samadov,Arno van den Bos,Karan Kochhar and Deepti Siddhanti.The draft also benefitted from the inputs and comments of external experts,including Pierpaolo Cazzola(University of California Davis and Columbia University)

6、,Dolf Gielen(World Bank),Deger Saygin(OECD),and Aleksandra Waliszewska(E3G).The report was copy-edited by Jonathan Gorvett and a technical review was provided by Paul Komor.Editorial and communications support were provided by Francis Field,Stephanie Clarke and Daria Gazzola.The graphic design was p

7、rovided by Nacho Sanz.IRENA is grateful for the support received from the Government of Italy to produce this report.The report uses information collected in the context of the“Innovation For Renewable Energy Transitions”(IFRET)project funded by the European Union.For further information or to provi

8、de feedback:publicationsirena.orgThis report is available at:www.irena.org/publicationsDisclaimerThis publication and the material herein are provided“as is”.All reasonable precautions have been taken by IRENA to verify the reliability of the material in this publication.However,neither IRENA nor an

9、y of its officials,agents,data,or other third-party content providers provides a warranty of any kind,either expressed or implied,and they accept no responsibility or liability for any consequence of use of the publication or material herein.The information contained herein does not necessarily repr

10、esent the views of all Members of IRENA,or the G7 Presidency.The mention of specific companies or certain projects or products does not imply that they are endorsed or recommended by IRENA or the G7 Presidency in preference to others of a similar nature that are not mentioned.The designations employ

11、ed and the presentation of material herein do not imply the expression of any opinion on the part of IRENA or the G7 Presidency concerning the legal status of any region,country,territory,city or area or of its authorities,or concerning the delimitation of frontiers or boundaries.Cover photos:mykhai

12、lo pavlenko/S,Studio concept/S and motive56/SAbout IRENA The International Renewable Energy Agency(IRENA)is an intergovernmental organisation that supports countries in their transition to a sustainable energy future,and serves as the principal platform for international co-operation,a centre of exc

13、ellence,and a repository of policy,technology,resource and financial knowledge on renewable energy.IRENA promotes the widespread adoption and sustainable use of all forms of renewable energy,including bioenergy,geothermal,hydropower,ocean,solar and wind energy in the pursuit of sustainable developme

14、nt,energy access,energy security and low-carbon economic growth and prosperity.www.irena.org IRENAs World Energy Transitions Outlook presents a comprehensive and cost-effective pathway to limit global average surface temperature rise to 1.5C above pre-industrial levels by 2050.To achieve this,it is

15、necessary to decarbonise all sectors of the economy by around mid-century.However,there are currently sectors that are hard to decarbonise-namely heavy-duty trucks,shipping,aviation,iron and steel,and chemicals and petrochemicals.These sectors alone represent a quarter of the worlds energy consumpti

16、on and a fifth of total CO2 emissions.This is likely to increase in the coming decades if they continue to rely on fossil fuels.Renewables can play a central role in decarbonising these hard-to-abate sectors,and solutions are increasingly available today;yet despite promising progress and increased

17、attention from policy makers,none of the hard-to-abate sectors is on track to reach net-zero emissions by mid-century.The acceleration of decarbonisation in these hard-to-abate sectors requires decisive action from governments and the private sector,with far-reaching implications for national and in

18、ternational policy,technology and infrastructure planning,global commodity markets,international supply chains,and business models.The G7 can play an influential role in spearheading decarbonisation efforts by adopting the 11 recommendations presented in this report.The Group can also work alongside

19、 non-G7 countries by sharing best practices,removing trade barriers,and establishing common standards and definitions for low-carbon commodities.This report-prepared to inform discussions during meetings among G7 senior officials as well the G7 Ministers Meeting on Climate,Energy and Environment in

20、Torino City on 29-30 April 2024 is the result of IRENAs continued support to the G7 and our Members in developing action plans that accelerate the decarbonisation of hard-to-abate sectors in order to achieve the 1.5C target of the Paris Agreement.FOREWORD Francesco La CameraDirector-GeneralInternati

21、onal Renewable Energy Agency4CONTENTSFigures .5Abbreviations .6Executive summary .81.Introduction .131.1Objectives and structure of this report.131.2Decarbonising hard-to-abate sectors.142.Challenges,solutions,and progress towards decarbonisation of the selected sectors .172.1Heavy-duty trucks.172.2

22、Shipping .242.3Aviation.322.4Iron and steel.382.5Chemicals and petrochemicals.463.Accelerating the transformation .523.1 Key considerations in the decarbonisation of hard-to-abate sectors.523.2Recommendations for the G7.55References .615 5 FIGURESFigure S1 Energy consumption and CO2 emissions for se

23、lected hard-to-abate sectors,2022.8Figure S2 Summary of key technological pathways and readiness assessment for selected sectors.9Figure 1 Energy consumption,CO2 emissions,activity metrics for selected hard-to-abate sectors,2022.15Figure 2 Main technology pathways for the decarbonisation of industry

24、 and transport.16Figure 3 Evolution and projections to 2030 for battery cell energy density(left)and costs(right).19Figure 4 Summary of decarbonisation pathways and infrastructure needs for heavy-duty trucks.20Figure 5 CO2 emissions by main vessel types,2012-2023.25Figure 6 Cost comparison of renewa

25、ble marine fuels.28Figure 7 Summary of decarbonisation pathways and infrastructure needs for shipping.29Figure 8 Historical and projected CO2 emissions of the aviation sector,1990 2050 .33Figure 9 Production cost comparison of sustainable aviation fuels.35Figure 10 Summary of decarbonisation pathway

26、s and infrastructure needs for aviation.36Figure 11 Traditional pathways for steel production.39Figure 12 Share of production routes and their estimated emissions intensities.40Figure 13 Global steel demand and scrap availability,2020-2050.41Figure 14 Summary of decarbonisation pathways and infrastr

27、ucture needs for iron and steel.43Figure 15 Overview of feedstocks and petrochemical products.47Figure 16 Summary of decarbonisation pathways and infrastructure needs for chemicals and petrochemicals.50Figure 17 Summary of key technological pathways and readiness assessment of selected sectors.536AB

28、BREVIATIONSAFIR Alternative Fuels Infrastructure RegulationATAG Air Transport Action GroupBECCS bioenergy with carbon capture and storageBECCU bioenergy with carbon capture and utilisationBF blast furnaceBOF basic oxygen furnaceCBAM Carbon Border Adjustment MechanismCCfD Carbon Contracts for Differe

29、nceCCOD Carbon Contracts for DifferenceCCUS carbon capture,utilisation and storageCO2 carbon dioxideCOP Conference of the PartiesCORSIA Carbon Offsetting and Reduction Scheme for International AviationCTE Committee on Trade and EnvironmentDAC direct air captureDC direct currentDRI direct reduced iro

30、nEJ exajoulesEAF electric arc furnaceECEG European Chemical Employers GroupEU European UnionEU ETS European Union Emissions Trading SystemEUR eurosEV electric vehicleFAME fatty acid methyl esterGHG greenhouse gasG7 Group of SevengCO2eq grammes of CO2 equivalentGDP gross domestic productGPP green pub

31、lic procurementGt gigatonsHEFA hydro-processed esters and fatty acidsHFO heavy fuel oilHVCs high-value chemicalsHVO hydrotreated vegetable oilHYBRIT Hydrogen Breakthrough Ironmaking TechnologyICAO International Civil Aviation OrganisationICCA International Council of Chemicals AssociationsICCT Inter

32、national Council on Clean TransportICE internal combustion engineIDDI Industrial Deep Decarbonisation InitiativeIEA International Energy AgencyIGO intergovernmental organisationIMO International Maritime OrganisationIRENA International Renewable Energy AgencyISO International Standard Organisationkm

33、 kilometreskW kilowattkWh kilowatt hourLNG liquefied natural gasLPG liquefied petroleum gasLTAG long-term aspirational goalMGO marine gasoilMt million tonnes7 7 MW megawattOECD Organisation for Economic Co-operation and DevelopmentPBtL power and biomass-to-liquidpkm passenger kilometrePV photovoltai

34、cSAF sustainable aviation fueltkm tonne kilometreTBT technical barriers to tradeTEN-T Trans-European Transport NetworkTESSD Trade and Environmental Sustainability Structure Discussionsteu twenty-foot equivalent unitTRL technical readiness levelUSD United States dollarVLSFO very low-sulphur fuel oilW

35、ETO World Energy Transitions OutlookWh/kg watt hours per kilogramme8EXECUTIVE SUMMARYThe Group of Seven(G7)has echoed the call from the International Renewable Energy Agency(IRENA)to accelerate the pace and scale of renewable energy deployment,highlighting its importance not only as an effective mea

36、ns of reducing emissions and enhancing energy security,but also driving economic growth and creating jobs.This report aims to provide actionable recommendations that the G7 can follow to accelerate the global efforts to decarbonise select“hard-to-abate”sectors,elaborating on the technological pathwa

37、ys and enabling conditions needed to achieve this goal.Limiting the global average surface temperature rise to 1.5C above pre-industrial levels will require all sectors of the economy to decarbonise by 2050.This is a great challenge that will require massive new investments and profound changes in t

38、he way energy systems operate.For some sectors,such as passenger road transport,the path to net-zero emissions is clear,as evidenced by the exponential rise in electric vehicle sales.The pace of transformation in some other sectors,however,is much slower.Some industrial and transport sub-sectors are

39、 substantial greenhouse gas(GHG)emitters and are harder to decarbonise due to their physical,technological or market particularities.This report focuses on five hard-to-abate sectors:road freight transport,shipping,aviation,iron and steel,and chemicals and petrochemicals.These five sectors account f

40、or roughly a quarter of the worlds energy consumption and are responsible for around a fifth of total CO2 emissions(FigureS1).Renewables can play a central role in the decarbonisation of all hard to abate sectors.The drastic cost reductions that we have observed in recent years make renewable power

41、the cheapest source of carbon-neutral energy worldwide.Furthermore,there is potential for further cost reductions through technological learning and economies of scale.Source:(IEA,2023a).Note:EJ=exajoules;Gt=gigatonnes;CO2=carbon dioxide.3%ShippingHeavy-duty trucksIron and steelChemicalsOthersAviati

42、on9%7%4%5%2%2%4%6%3%3%75%80%411EJ202237GtCO2Figure S1 Energy consumption and CO2 emissions for selected hard-to-abate sectors,2022ExEcutivE Summary9The full decarbonisation of the hard-to-abate sectors will require a combination of approaches,given the characteristics of each sector.However,most emi

43、ssion reductions will have to be achieved through a combination of five main pathways which rely primarily on renewable energy and energy efficiency as described in FigureS2.Note:Increasing circle size indicates higher relevance to the decarbonisation efforts of each sector,i.e.larger circles indica

44、te higher relevance and smaller circles lesser relevance.Circle filling indicates technology readiness,i.e.filled circles indicate a technology is ready for deployment,while empty circles indicate a lack of readiness.The dashes indicate negligible or no relevance.Heavy-dutytracksShippingAviationIron

45、 and steelChemicalsandpetrochemicalsReduced demand and improved energy efciencyDirect use of clean electricity.Indirect use of clean electricity via synthetic fuels and feedstocksDirect use of renewable heat and biomassUse of carbon dioxide capture,utilisation,and removal measures-Relevance+-Readine

46、ss+Figure S2 Summary of key technological pathways and readiness assessment for selected sectorsDECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G710The transition in hard-to-abate sectors requires fundamental shifts,rather than gradual steps.The window of opportunity for act

47、ion to counter the global climate threat and meet the 1.5C target of the Paris Agreeme is closing fast.Meeting the climate agenda requires solutions beyond partial emission reductions.Decision makers should prioritise solutions that are consistent with net-zero emissions,avoid delaying their decarbo

48、nisation objectives and the risk of future stranded assets.Most of these solutions rely on renewable energy.Direct electrification will play an increasing role,with important contributions in multiple applications.Some of these solutions are already mature,or close to technological maturity.These in

49、clude:the use of electric arc furnaces for steelmaking,which will become more important as the share of recycled steel increases in the coming decades;battery electric trucks,which are at a technological inflection point and becoming increasingly available;heat pumps for low to medium temperature he

50、ating in industry;and cold ironing at ports.Some other applications of direct electrification,while having great potential,still need further development.These include:electric crackers to produce primary chemicals;electrolysis of iron ores;and electric or hybrid aircraft and ships for short distanc

51、es.Bioenergy and synthetic fuels will play a critical,complementary role to electrification.Scaling up sustainable,low-carbon bioenergy solutions is not only key to the decarbonisation of shipping and aviation.It is also critical in providing feedstocks for chemicals and as a potential carbon source

52、 for synthetic fuels.Indirect electrification i.e.via the production of renewable hydrogen is also set to play an important role in achieving deep emissions reductions in these sectors.It can do this as a reductant in the production of iron in primary steel production,as a form of synthetic fuels fo

53、r shipping and aviation,and as a feedstock for chemical industries.These pathways will have to be complemented by continuous energy efficiency improvements,the application of the principles of the circular economy,and behavioural and process changes that reduce demand.Additionally,emissions can be f

54、urther reduced through the application of CO2 capture,utilisation and/or removal measures,provided that these technologies achieve the necessary improvements in performance and economics to make them technically scalable and economically viable.While technology is increasingly available,in the absen

55、ce of sufficiently high and widespread carbon pricing,a timely transition in hard-to-abate sectors will almost certainly require paying a premium over the cost of fossil-based systems.Cost differentials differ widely by sector and application.Despite promising progress and increased attention from p

56、olicy makers,none of the hard-to-abate sectors is on a trajectory compatible with reaching net-zero emissions by mid-century.Several enabling conditions need to be put in place to accelerate the decarbonisation of hard-to-abate sectors.These will require decisive action by governments,as well as by

57、the private sector.They also have fundamental implications in terms of national and international policy and regulatory environments,technology and infrastructure planning,global commodity markets,international supply chains and business models.ExEcutivE Summary11To achieve this,this report provides

58、 the following recommendations for the G7:On creating an enabling policy environment1.Establish sector-specific decarbonisation targets:G7 countries can support the transition by establishing long-term,sector-specific,national objectives with clear intermediate milestones.Beyond national policies,G7

59、 members can work with other countries,within and beyond the G7,towards further international convergence in the decarbonisation objectives for key traded commodities such as steel,ammonia,and methanol,as well as aviation and shipping fuels.2.Take further steps towards creating a level playing field

60、 for green technologies.G7 countries can accelerate the adoption of green technologies in hard-to-abate sectors by implementing national carbon pricing policies that internalise the full value of the negative environmental externalities of fossil energy.Aligning energy taxes with decarbonisation obj

61、ectives for example,by reducing relative taxation of electricity vis a vis that of fossil fuels can also play an important role by driving the electrification of heat and transport applications.Furthermore,G7 countries can work with other countries,within and beyond the G7,towards further convergenc

62、e in international carbon pricing for example,through sector-specific international agreements.On fast-tracking infrastructure deployment and technology adoption3.Accelerate the deployment of renewable power supply in alignment with COP 28s pledge:G7 countries can support the transition in hard-to-a

63、bate sectors by scaling up deployment of renewable power supply in line with the COP28 pledge of tripling renewable capacity by 2030.This will require additional efforts,including a substantial scaling up of investments and updating of policies and regulations.Electrification of hard-to-abate-sector

64、s may also result in opportunities to optimise investments in power systems,as well as their deployment,and operation.A holistic approach to define the location of new renewable generation facilities could lead to reduced costs for the energy transition by minimising storage needs and the need to tr

65、ansport electricity and other energy carriers produced with electricity.4.Scale up sustainable bioenergy production and sustainable carbon sourcing:G7 countries can support the transition in hard-to-abate sectors by working within and beyond the G7 to scale up global sustainable biomass supply chain

66、s.This can be achieved with policies that provide incentives for the production and/or use of bioenergy,coupled with strict sustainability governance procedures and regulations.5.Kick-start deployment of production capacity for green hydrogen derivatives:G7 countries can accelerate the transition in

67、 hard-to-abate sectors by supporting the first wave of commercial-scale plants to produce low carbon commodities using green hydrogen such as ammonia,methanol and iron.DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G7126.Enhance planning to accelerate the deployment of crit

68、ical infrastructure:G7 countries can support the transition in hard-to-abate sectors by strengthening cross-sector planning and international co-ordination in energy,industry,trade,transport,and the environment.They can also support the transition by accelerating permitting and deployment of critica

69、l energy infrastructure.Among others,this includes power grids paired with smart electrification strategies bioenergy conversion plants,hydrogen networks,and fuel terminals in ports and airports.7.Drive the adoption of innovative technologies to avoid lock-in:G7 countries can accelerate the global t

70、ransition in hard-to-abate sectors by prioritising and promoting the deployment of technologies that are consistent with net-zero emissions.G7 members can also work with non-G7 countries towards the widespread adoption of such new solutions,particularly in developing nations.This can be done through

71、 inter alia technology co-operation programmes,the exchange of best practices,and many other methods to avoid lock-in.On driving markets and financial flows8.Create initial markets for low carbon commodities:G7 countries can support the transition in hard-to-abate sectors by establishing green publi

72、c procurement programmes or mandates for low carbon commodities.G7 members can also work within and outside the G7 to accelerate international convergence in definitions,standards,thresholds,and certification procedures to enable the international trade of such low carbon commodities.9.Bridge the fi

73、nance gap:G7 countries can drive an increase in global investment flows towards hard-to-abate sectors by working together with the private sector and financial institutions in de-risking projects within and outside the G7.Government support for project bankability can be implemented through several

74、mechanisms,such as via the provision of guarantees,concessional loans,and blended finance,among other instruments.On developing a skilled workforce10.Support the development of a skilled workforce:G7 countries can play a significant role in developing the skills needed for the transition in hard-to-

75、abate sectors.Potential measures include exchanging information on innovative technologies and best practices and providing financial support to specialised educational programs and trainings.On leveraging international co-operation11.Foster international co-operation:G7 countries can work together

76、with developing countries towards mutually beneficial partnerships to decarbonise supply chains for industrial commodities.This can be done through co-operative long-term investment planning that results in a lower cost of decarbonisation for all.131.INTRODUCTION1.1 Objectives and structure of this

77、reportThe Group of Seven(G7)has echoed the call from the International Renewable Energy Agency(IRENA)to accelerate the pace and scale of renewable energy deployment.1 This highlights the importance of renewables not only as effective means of reducing emissions and enhancing energy security,but also

78、 of driving economic growth and creating jobs.In 2023,the G7 stated that they would“accelerate the deployment of renewable energies such as solar,onshore/offshore wind,hydropower,geothermal,sustainable biomass,biomethane and tidal using modern technologies,as well as invest in the development and de

79、ployment of next-generation technologies,and develop secure,sustainable and resilient supply chains”(G7 Ministers of Climate,Energy and the Environment,2023).The 2024 G7 Presidency requested IRENAs advice on how the G7 could contribute to accelerating global energy transitions.While the energy trans

80、ition will involve the decarbonisation of the power,transport,and heating and cooling sectors,there are elements of the energy system that are more complex and costlier to decarbonise.This is due to technological limitations,economic and geopolitical concerns and these sectors extensive demand for e

81、nergy.We refer to these sectors as“hard to abate”.This report elaborates on the technological pathways and systemic innovations needed to decarbonise five of these sectors:heavy-duty trucks,shipping,aviation,iron and steel,and chemicals and petrochemicals.This report aims to provide actionable recom

82、mendations that the G7 can follow to accelerate global efforts to decarbonise these sectors.This first chapter includes a short introduction to the decarbonisation challenge,particularly in the context of the five hard-to-abate sectors addressed in this study,while also looking at the five decarboni

83、sation pathways that could help reduce emissions to net-zero.Chapter 2 delves deeper into the status,challenges,and proposed solutions for the decarbonisation of each of the five hard-to-abate sectors mentioned above.Chapter 3.1 draws conclusions providing a more general perspective on decarbonisati

84、on,highlighting cross-cutting issues and commonalities in terms of challenges,enabling conditions and solutions for the different sectors.Finally,Chapter 3.2 makes recommendations about how the G7 can support the successful decarbonisation of these sectors.1 See:www.irena.org/News/pressreleases/2023

85、/Apr/G7-Communique-Echoes-IRENAs-Call-for-Rapid-Deployment-of-Renewables DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G714To complement this work,IRENA prepared two other studies for the 2024 G7 Presidency.The first of these outlines the implications for the G7 of the ple

86、dge to triple renewable power by 2030 made at COP28.This study then offers recommendations on how to materialise those ambitions.The second study focuses on energy transitions that are inclusive and maximise local value in the African region.It does this by outlining the key infrastructure investmen

87、t opportunities and critical enabling conditions available for the African continent to enhance its role as a global partner in the energy transition.1.2 Decarbonising hard-to-abate sectorsLimiting the global average surface temperature rise to 1.5C above pre-industrial levels will require all secto

88、rs of the economy to decarbonise by 2050.This is a great challenge that will require massive new investments and profound changes in the way energy systems operate.For some sectors,such as electricity supply,the path to net-zero emissions is clear.Most technologies for this sector are mature and com

89、mercially available,and the transformation is accelerating.Renewable technology costs have also dropped drastically over the last couple of decades,resulting in unprecedented deployment rates.In 2023,87%of new electricity capacity additions globally were renewable up from 53%in 2013(IRENA,2024a).Som

90、ething similar is happening with passenger road transport,where battery electric vehicle(EV)adoption is rising exponentially.Some 13.6 million electric passenger cars were sold in 2023 alone roughly 15%of total global automobile sales and a 425%increase since 2020(ACEA,2024;Carey,2024;EV-Volumes,202

91、3).The pace of transformation in some other sectors,however,is much slower.Some industrial and transport sub-sectors are substantial GHG emitters and are harder to decarbonise due to their physical,technological or market particularities.This report focuses on five hard-to-abate sectors:road freight

92、 transport,shipping,aviation,iron and steel,and chemicals and petrochemicals.These five sectors account for roughly a quarter of the worlds energy consumption and are responsible for around a fifth of total CO2 emissions(Figure1).oksana.perkins/S,frank_peters/S,phoenix_preeda/S,Vladimir Mulder/S and

93、 Red ivory/Sintroduction15The steps that need to be taken to decarbonise these sectors have long been debated.Progress on the implementation of these steps,however,has so far been very slow.In recent years though,two important factors have changed.The first is the unprecedented social and political

94、momentum now pushing for an acceleration in decarbonisation.The second is the technological maturity and increasing competitiveness of renewable power and other enabling technologies,potentially bringing the solutions closer to reality for some of the decarbonisation challenges in these sectors.IREN

95、As perspective on achieving net-zero CO2 emissions(IRENA,2020),recognises that while each sector is different and will require different approaches,most emission reductions will have to be achieved through a combination of five main pathways which rely primarily on renewable energy and energy effici

96、ency.(Figure2).Source:(ICAO,2023a;IEA,2023a,2023b;UNCTAD,2022).Note:EJ=exajoules;Gt=gigatonnes;tkm=tonne kilometre;pkm=passenger kilometre.3%Heavy-dutytracksShippingAviationIron and steelChemicalsandpetrochemicals30 trilliontkm110 trilliontkm6 trillion pkm220 billion tkm 1.8 billiontonnes 719 millio

97、ntonnesActivity26.8 11.2113516Energyconsumption EJ/year1.8CO2 emissionsGt0.860.82.81.3ShippingHeavy-duty trucksIron and steelChemicalsOthersAviation9%7%4%5%2%2%4%6%3%3%75%80%411EJ202237GtCO2Figure 1 Energy consumption,CO2 emissions,activity metrics for selected hard-to-abate sectors,2022DECARBONISIN

98、G HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G716The window of opportunity for meaningful action to counter the global climate threat is closing fast.The climate agenda requires solutions beyond partial emission reductions.Decision makers should prioritise solutions that are consiste

99、nt with net-zero emissions,and avoid delaying their decarbonisation objectives and the risk of future stranded assets.Most of these solutions rely on renewable energy.The following chapter takes a deeper look into each of the five hard-to-abate sectors mentioned above,analysing their status and chal

100、lenges.It then shows how the five technological pathways also outlined above can be applied towards the full decarbonisation of those sectors.Reduced demand and improved energy efciencyReducing the demand and intensity for energy and materials through a range of actions.These include energy efciency

101、,behavioural and process changes,industry relocation andthe application of the principles of the circular economy.Direct use of clean electricityReplacing technologies and processes that rely on fossil fuels with alternatives powereddirectly by clean electricity.This not only displaces fossil fuel u

102、se,but also increases theefciency of these processes.Indirect use of clean electricity via synthetic fuels and feedstocksSourcing energy and feedstocks from hydrogen and its derivatives,produced usingclean electricity and sustainably sourced carbon,obtained from non-fossil fuel sources.Direct use of

103、 renewable heat and biomassSatisfying heat requirements with renewable heat from solar thermal,geothermal or bioenergytechnologies,and directly replacing fossil fuels with biofuels where direct electrificationis not possible.Implementation of CO2 capture,utilisation,and removal measuresCO2 emissions

104、 from processes where emissions cannot be fully eliminated can be captured andstored permanently,or used in ways in which it will not be released later.To avoid net CO2 additionsto the atmosphere,the carbon utilisation pathway needs renewable sources of carbon or theapplication of a closed loop wher

105、e the CO2 resulting from combustion is recycled back into fuels.Figure 2 Main technology pathways for the decarbonisation of industry and transportTR STOK/S172.CHALLENGES,SOLUTIONS,AND PROGRESS TOWARDS DECARBONISATION OF THE SELECTED SECTORS 2.1 Heavy-duty trucksHeavy-duty trucks2 play a crucial rol

106、e in the global economy.Since 2010,the volume of goods transported by this mode of transport has increased by over 30%,a similar increase to that of global gross domestic product(GDP)3(IEA,2023a;World Bank,2024).As a result of this strong correlation between road freight activity and economic growth

107、,heavy-duty road truck activity is expected to more than double by mid-century(ITF,2023;IEA,2023a;MPP,2022).Fast deployment of zero-emissions trucks4 is therefore essential if dependence on fossil fuels is to be reduced and air quality improved,benefiting the climate and society.Emissions and energy

108、 useHeavy-duty trucks represent only about 9%of global vehicle stock(IDTechEX,2019),yet they are responsible for almost a quarter of all transport-related CO2 emissions.In 2022,this figure translated to around 5%of global CO2 emissions,or,in absolute terms,around 1.8 Gt of CO2(IEA,2023a).Put another

109、 way,emissions from heavy-duty trucks are larger than those from the international aviation and shipping sectors combined.Today,heavy-duty trucks rely almost exclusively on diesel,petrol and natural gas.Biofuels account for less than 5%of total consumption in the sector(IEA,2023a).In the last few ye

110、ars,the sector has made some progress towards decarbonisation.The emissions intensity of new trucks has decreased by around 14%since 2019,5 partly due to efficiency measures,operational improvements,and an increase in biofuels in the fuel mix(WEF,2023).2 Heavy-duty trucks include medium trucks(3.5 t

111、onnes to 15 tonnes)and heavy trucks(above 15 tonnes).3 At constant,2015 US dollars(USD),global GDP increased from USD 65 trillion in 2010 to close to USD 90 trillion in 2022(World Bank,2024).4 In this report,zero emission trucks refers to trucks with zero tailpipe emissions.5 The emission intensity

112、for new trucks dropped from 109.3 grammes of CO2 equivalent(gCO2eq)/tkm to 94.4 gCO2eq/tkm between 2019 and 2022(WEF,2023).DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G718Decarbonisation pathwaysGlobal heavy-duty truck activity is expected to more than double by 2050.Wit

113、h continuous reliance on diesel and limited action taken,by then,heavy-duty trucks alone could account for over 75%of all road freight-related CO2 emissions and emit between 2.3Gt and 3Gt of CO2(MPP,2022;IEA,2023a).In the short-to medium-term,the carbon footprint of the sector can be reduced by intr

114、oducing stringent efficiency standards for trucks.Beyond efficiency,a modal shift from road-to rail-based freight can further reduce the energy intensity of the transport sector.However,modal shifts typically require substantial investments in infrastructure that can take years or even decades to ma

115、terialise.In the long term,a combination of renewables-based options-such as the use of biofuels,adoption of electric trucks,and the use of renewable hydrogen and synthetic fuels-is required to reach net-zero emissions in the sector.From those renewables-based options,significant progress has been o

116、bserved in terms of electric trucks owing to several factors.These include:their superior efficiency;6 expected earlier market availability at scale;and benefits from synergies with technological advances in battery electric cars,which are already being deployed in large volumes.The costs and perfor

117、mance improvements of batteries have also greatly improved the economic case for EVs in recent years.From 2010 to 2023,the weighted average price of lithium-ion battery packs declined 89%,to USD139per kilowatt hour(kWh)(BNEF,2023a).Over the same period,the cost of lithium-ion battery cells dropped t

118、o around USD100/kWh,while in 2023,the energy density of some newly commercialised batteries crossed the 500watt-hours per kilogramme(Wh/kg)mark(RMI,2023).As a result,the scope of application of batteries is quickly expanding to a broader set of road vehicle segments and types of services.Accordingly

119、,electric trucks are gaining attention and emerging as the most promising technological solution for decarbonising the heavy-duty segment.Electric trucks have the potential to be cost-competitive in the absence of subsidies and are becoming increasingly available for wider adoption.Yet,even if there

120、 is a rapid adoption of electric trucks,a large fleet of internal combustion engine(ICE)vehicles will unavoidably be in operation for the next two to three decades.For these,emission reductions can also be achieved in the short-to medium-term by using sustainably sourced biomass-based diesel substit

121、utes.7 However,in the longer run,the use of sustainably sourced biomass needs to be prioritised in those sectors where there is a limited scope for electrification and other low-carbon alternatives.6 Electric powertrains in electric vehicles typically operate at energy efficiencies above 90%,while i

122、nternal combustion engines in vehicles typically convert less than a third of the energy in the fuel into useful mechanical energy(Martin Weiss et al.,2020).7 Fatty acid methyl esters(FAME)are produced via the esterification of vegetable oils and fats and are also known as biodiesels.Hydrotreated ve

123、getable oil(HVO),also known as hydro-processed esters and fatty acids(HEFA),is commonly referred to as renewable diesel(IRENA,2020).challEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 19There are also ongoing efforts to explore the use of hydrogen trucks.However,the eco

124、nomics and technical characteristics8 of these vehicles lag far behind those of electric trucks.Moreover,the use of green hydrogen should be prioritised in sectors where it adds the most value to decarbonisation efforts,i.e.where direct electrification with renewable power is not an option.Such appl

125、ications include the production of key industrial commodities such as ammonia,steel and the production of synthetic fuels for long haul aviation and shipping.In these,green hydrogen can be a complementary solution to sustainable biofuels.Source:(Walter et al.,2023).FastFaster800700600500400300200100

126、03002001000Top-tier battery cell energy density outlook(Wh/kg)Battery cell cost outlook(USD/kWh)2000200520025203020030Figure 3 Evolution and projections to 2030 for battery cell energy density(left)and costs(right)8 For example,about three times more renewable electricity suppl

127、y is needed to power a hydrogen truck as compared to a battery electric truck.s_oleg/SDECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G720The carbon footprint of the sector can be reduced by introducing stringent efciency andemissions standards for trucks.Beyond efciency,in

128、cases where there is large demand of freightservices such as major transport corridors and adequate infrastructure provision,a modal shiftfrom road-based freight to rail can further reduce the energy intensity of the transport sector.Battery electric trucks are set to be the leading pathway for deca

129、rbonising road freight transport.Compared to other low-carbon alternatives,electric trucks are highly efcient,soon to becost-competitive,and increasingly available now for wider adoption.Faster deployment ofcharging infrastructure is essential.There are ongoing eforts to explore the use of hydrogen

130、trucks,but their economics andtechnical characteristics lag far behind those of electric trucks.Emission reductions can also be achieved in the short-to medium-term using biomass-baseddiesel substitutes,such as biodiesels and renewable diesel.This is particularly relevant for thefleet of ICE vehicle

131、s which will unavoidably be in operation for the next two to three decades.Figure 4 Summary of decarbonisation pathways and infrastructure needs for heavy-duty trucksKey infrastructure needs for heavy-duty trucks Fast charging infrastructure for e-trucks in rest areas and slow charging in depots Exp

132、ansion and reinforcement of distribution grids Digital infrastructure for smart charging Stationary storage close to charging stations to reduce peak loadsTracking ProgressRoad freight decarbonisation is approaching a turning point,driven by technological progress and growing regulatory and market p

133、ressures.It is also set to advance more rapidly than anticipated.In recent years there has been rapid growth in zero-emission vehicle models entering the market.The Zero-Emission Technology Inventory(ZETI)database9 shows that there are currently 116 heavy-duty truck models existing and announced.Of

134、these,99 are battery electric and the remaining 17 are fuel cell-based.In terms of performance,since 2020,the average ranges for zero-emission trucks have increased by 11%.The availability of vehicles with a range of 500 miles(805 km)indicates promising capabilities for longer hauls(Global Drive to

135、Zero,n.d.).challEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 21In terms of vehicle sales,electric medium-and heavy-duty trucks accounted for 1.2%of global truck sales in 2022,with over 60 000 units sold.China was the main market,accounting for 85%of global sales(IEA,2

136、023c).In 2023,a total of 2 600 zero-emission heavy-duty trucks were sold in the European Union(EU).This figure is over three times the total sold in 2022(820),indicating strong growth in market demand(ICCT,2024a).Despite this progress,however,the current pace of adoption of electric trucks is less t

137、han what is needed to achieve climate targets.Under IRENAs 1.5C Scenario,EVs should account for nearly two-thirds of the heavy-duty vehicle stock by 2050(IRENA,2023a).This implies that electric heavy-duty trucks have to become widely available and sold in significant volumes in most jurisdictions ar

138、ound the world within this decade.The major challenges,including higher upfront costs,insufficient charging infrastructure,an imbalance in taxation of electricity vis-a-vis fossil fuels,and only incipient supply chains to meet the fast demand growth of electric trucks,need to be addressed.Different

139、charging models for heavy-duty electric vehicles are being explored and pilot prototypes are emerging.Electric trucks have been relying on off-shift charging for most of their energy,typically done at private or semi-private charging depots and usually overnight.There is a global push to implement f

140、ast or ultra-fast charging options,however,as a necessary step in making regional and long-haul operations technically and economically viable.Notable examples include a joint venture by Daimler,Volvo,and Traton Group,which aims to roll out a large-scale public charging network for heavy-duty trucks

141、 and coaches in Europe.This would have at least 1 700 fast and ultra-fast charging points(Milence,2022).Tesla plans to build electric semi-truck charging stations between California and Texas to reach 70%battery capacity,in alignment with the US mandatory 30-minute break for truck drivers after 8hou

142、rs of driving(Electrek,2023).Forum Mobility,a service provider,plans to deploy over 1 000 direct current(DC)fast chargers for heavy-duty electric trucks at the San Pedro and Oakland ports(Forum Mobility,n.d.).Alternatives to charging stations,such as electric road systems,10 are currently being demo

143、nstrated,although only a few countries,such as Sweden,are advancing with specific plans.As in the electric passenger vehicle segment,a variety of charging standards are also currently under development and are soon to be adopted.In 2022,the industry association CharIN introduced the Megawatt-level C

144、harging Standard.This has a maximum power rating of 3.75megawatts(MW)and is scheduled for adoption in 2024,primarily in Europe and North America(CHARIN,2022).Elsewhere,in September 2023,China established the“ChaoJi”charging standard,which has a maximum power of 1.2MW.Commercialisation of chargers wi

145、th power levels rated in the megawatts calls for significant investment,however,as stations with such high requirements will incur significant installation,grid connection and upgrade costs.9 See:https:/globaldrivetozero.org/tools/zeti-data-explorer/10 This is infrastructure that allows for charging

146、 while driving and is currently under consideration in Sweden for electrifying long-haul trucking.DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G722Advanced power system planning,and grid management measures are emerging to accommodate charging needs,along with the raising

147、 market share.Alternative solutions,such as installing stationary storage,integrating local renewable capacity via the creation of clean energy corridors,and using smart charging,can help reduce infrastructure costs related to grid connection.They can also reduce electricity procurement costs.Smart

148、charging measures have already been adopted in the UnitedKingdom(which mandated compliance with its Open Charge Point Protocol in 2022),Belgium and Luxembourg(IRENA,2023b).On the policy side,governments at different levels have set sales targets and started implementing incentives to encourage the u

149、se of zero-emission trucks.Under the global Memorandum of Understanding on Zero-Emission Medium-and Heavy-Duty Vehicles,27 countries around the world have pledged that zero-emission medium-and heavy-duty vehicles will represent 30%of their new truck sales by 2030,and 100%by 2040,at the latest(IEA,20

150、23c).In California,the Advanced Clean Truck policy requires manufacturers to reach a sales goal of 40%zero-emission trucks by 2035.Since 2023,the US Inflation Reduction Act has provided tax credits of up to USD40 000 per vehicle for the purchase of zero emission heavy-duty electric trucks.The aim of

151、 this is to bring the cost per mile of these vehicles down to par with traditional diesel trucks(US Government,2023).Stricter regulations and stringent standards are being formulated in various jurisdictions.In Europe,new CO2 emissions standards have been introduced that set a 45%emissions reduction

152、 target for heavy-duty vehicles by 2030,compared to 2019 levels,increasing to 90%by 2040(EC,2023a).In the UnitedStates,the GHG for Heavy-Duty Vehicles-Phase 3 standards for 2027 also aim to bring significant reductions in pollutant emissions from trucks(US EPA,2023).Other major economies such as Chi

153、na,Canada,India,and Japan also apply standards to heavy-duty vehicles(The Climate Change Authority,2023).In parallel,to increase demand for zero-emission trucks,some governments have started committing to a 100%phase-out of ICE medium-and heavy-duty trucks in the long term.Indeed,according to the In

154、ternational Council on Clean Transport(ICCT)tracking progress tool,eight governments have set ambitious ICE truck phase-out targets,aiming for at least 40%of all sales for electric trucks by 2050(ICCT,2024b).Policies specifically targeting the rollout of charging infrastructure,grid extensions and m

155、odernisation are also starting to emerge.Europe is well advanced on this front,with the EUAlternative Fuels Infrastructure Regulation(AFIR).This aims to install electric recharging stations for heavy-duty vehicles every 60km along the Trans-European Transport Network(TEN-T)core,with complete network

156、 coverage by 2030(EC,2023b).The stations will have a minimum output of 350kW.This regulation could provide sufficient public charging infrastructure for the EU to reduce CO2 emissions from new heavy-duty vehicles by 65%substantially more than the official 45%reduction target across the EU(T&E,2023).

157、challEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 23The United States,meanwhile,is advancing with the National Electric Vehicle Infrastructure Formula Program.This has allocated funding of USD885million for 2023 to support the installation of charging stations along 1

158、22 000km of highways(US DOE,n.d.).In addition,the country recently unveiled its first-ever national strategy to accelerate the charging infrastructure for freight trucks(US DOE,2024).In addition,California plans to build a clean highway corridor,called The West Coast Clean Transit Corridor,with char

159、ging facilities from San Diego to British Columbia for heavy-and medium-duty trucks(IRENA,2023b).The road freight industry is increasingly considering zero-emission trucks as a viable option for decarbonising their fleets.More than 3 600 companies worldwide have committed to science-based targets,wi

160、th some actively seeking zero-emission trucks and willing to pay a premium for them(MCFM,2022).Several original equipment manufacturers are leading the way by establishing ambitious goals to produce battery-electric trucks.For instance,Daimler Truck expects up to 60%of its European sales to come fro

161、m EVs by 2030,while Traton and Volvo aim to achieve a 50%market share within the same timeframe(Soulopoulos,2023).A few well-known private companies,such as Maersk,Sysco,Holcim,Schneider National and Rio Tinto,have ordered thousands of heavy-duty electric trucks from Daimler,Volvo,Scania,and others.

162、Industry initiatives such as Road Freight Zero and Smart Freight Centres Fleet Electrification Coalition are actively working on aggregating demand for electric trucks,tackling challenges relating to charging infrastructure and identifying and developing innovative financing solutions for zero-emiss

163、ion trucks.11Innovative business models are also emerging to accelerate the adoption of electric trucks.For instance,Scania has introduced a pay-per-use model that provides transport companies with access to electric truck solutions.This model makes it easier for carriers to switch to electric truck

164、s,eliminating upfront costs and potential residual value concerns(Scania,2023).11 See:www.weforum.org/projects/decarbonizing-road-freight-initiative/and www.smartfreightcentre.org/en/projects/ongoing-projects/fleet-electrification-coalition/.Flystock/SDECARBONISING HARD-TO-ABATE SECTORS WITH RENEWAB

165、LES:PERSPECTIVES FOR THE G7242.2 ShippingMaritime transport is vital to the worlds economy,enabling international trade and commerce,and facilitating the movement of goods and resources across the world.In 2022,international seaborne trade reached 11billion tonnes,or over 80%of global trade by volum

166、e,mainly dominated by dry bulk,oil shipments and containerised trade(UNCTAD,2023).About a third of seaborne trade involves the transportation of fossil energy products(Jones et al.,2022).This means that maritime transport is not only a consumer of energy,but also a means for its transport.The decarb

167、onisation of power systems,road transport and heat production with renewable electricity will result in steep demand reductions for fossil energy products and consequently,for the shipping of these energy commodities.Yet the sector will still play an important role in unlocking and accelerating the

168、decarbonisation of other transport and industrial sectors,helping satisfy the resulting demand for green fuels and chemicals instead.Ships are long-lived assets,with the vessels deployed in the next few years largely shaping the fleet and fuel mix that will occur two-to-three decades from now.This h

169、ighlights the need for the transition to renewable-energy-powered vessels to happen as soon as possible,or the world risks missing 2050 net-zero targets.Emissions and energy useMaritime transport is amongst the least carbon-intensive transport modes,in terms of emissions per passenger kilometre(pkm)

170、and per tonne kilometre(tkm)(European Environment Agency,2023).However,the sector is still a major polluter given the sheer magnitude of its activity.In 2022,energy consumption in the shipping sector reached 11.2EJ.At 3%of total global energy consumption,this also equates to 10%of all transport-rela

171、ted energy consumption,worldwide(IEA,2023a).Maritime trade activity has roughly doubled in the last 20 years,going from 55trillion tkm in 2002 to 110 trillion tkm in 2022(UNCTAD,2022).According to the projections used by the International Maritime Organisation(IMO)in their 2020 GHG study,this activi

172、ty is expected to increase by between 40%and 100%by 2050(IMO,2021a).The lower end of this range corresponds to scenarios with steep reductions in oil and coal demand due to the energy transition.This increase could also change depending on the future evolution of demand for natural gas.In 2022,the s

173、ectors CO2 emissions amounted to over 0.8Gt(Figure4).This is equivalent to between 2%and 3%of total global CO2 emissions,or roughly 10%of transport-related emissions(IEA,2023a).Roughly 80%of these emissions come from international shipping(IMO,2021a).challEngES,SolutionS,and progrESS towardS dEcarbo

174、niSation of thE SElEctEd SEctorS 25The shipping sector is heavily dependent on inexpensive,low-grade fossil fuels such as heavy fuel oil(HFO)and marine diesel oil.In 2020,the IMO introduced a global regulation aimed at significantly curbing sulphur oxide emissions(IMO,2021b).This directive prompted

175、a rapid and widespread change within the sector towards adopting very low sulphur fuel oil(VLSFO),or the installation of onboard scrubbers to curb these emissions.This showcased the ability of the sector to rapidly adapt and implement policy-driven changes.There are a number of net-zero compatible a

176、lternatives for conventional marine fuels,such as sustainably produced low-carbon biofuels,green e-fuels,or hybrid,power and biomass-to-liquid(PBtL)fuels.12 However,these all come at a considerable cost premium.Depending on the spot price of conventional marine fuels,these alternatives can be up to

177、twice the price for biofuels and three-to-four times,or even higher,for e-fuels(IRENA,2021a;Ship&Bunker,2024).Alternative fuel cost reductions will therefore be needed to turn shipping away from its fossil fuel dependency.Most trade activity is undertaken by container ships,bulk carriers and fuel an

178、d chemical tankers.While these types of vessels account for only about 20%of the global fleet,they are responsible for 80%-85%of the GHG emissions associated with the shipping sector(IMO,2021a;UNCTAD,2023).This means that targeted interventions can have outsized implications,in terms of emissions re

179、ductions.Source:(UNCTAD,2023).Note:The“Other”group includes vehicle and roll-on/roll-off ships,passenger ships,offshore ships and service and miscellaneous ships.1 0009008007006005004003002005200022202320132012Million tonnes of CO2 emissions(Mt)TankersDry bulk and ge

180、neral cargoContainerOtherFigure 5CO2 emissions by main vessel types, PBtL processes combine biomass-to-liquid(BtL)and power-to-liquid(PtL)processes to achieve higher carbon conversion efficiencies and lower production costs.DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES

181、FOR THE G726Decarbonisation pathwaysMaritime transport-related emissions have steadily increased over the last decade and are expected to reach 130%of their 2008 levels by 2050,if no action is taken(UNCTAD,2023).This highlights the urgency of moving away from the sectors current fossil fuel dependen

182、cy something that could be achieved through the application of several decarbonisation pathways.IRENAs 1.5C scenario estimates that roughly 17%of the emissions reductions necessary by 2050 could come from changes in global trade dynamics triggered by the energy transition.These changes would come ma

183、inly in the form of an overall reduction in global fossil fuel use.This would be caused by the decarbonisation of other sectors as they strive to become carbon neutral.This would,in turn,cause a reduction in fuel tanker activity and consequently a reduction in the sectors energy demand(IRENA,2023a).

184、Another important driver for decarbonisation would be the adoption of energy-efficient technologies and operational measures.These would include high-efficiency propellers,wind-assisted propulsion,waste heat recovery systems and speed optimisation.In terms of emissions reductions,energy efficiency i

185、mprovements can have an immediate impact and could potentially contribute 20%of the CO2 reductions the sector requires by 2050,according to IRENAs 1.5C scenario(IRENA,2023a).Savings from energy efficient technologies,beyond those mandated by the IMOs Energy Efficiency Design Index Phase 3,are estima

186、ted to be in the order of 25%for container vessels,18%for bulk carriers,18%for tankers and 26%for liquefied natural gas(LNG)carriers(MAN ES,2023).Energy savings alone will not be enough to take shipping all the way to net-zero emissions.The remaining emissions will need to be abated through the adop

187、tion of renewable-based alternatives.These include electric propulsion,biofuels and e-fuels that displace the use of conventional fossil-based marine fuels.According to IRENAs 1.5C scenario,these could contribute over 60%of the necessary emissions reductions(IRENA,2023a).Direct electrification can a

188、lso play an important role in the decarbonisation of vessels working short and inland routes(i.e.ferries and coastal and river transports).Todays battery technologies could already enable the electrification of vessels on such routes,as well as small cruise ships and ro-ro ships.In addition,electrif

189、ication of new ships with routes of up to 1 000km has been made possible by recent battery technology improvements.The two,700twenty-foot equivalent unit(teu)container ships built by COSCO Shipping Lines in 2023 are a good example of this(COSCO,2023;IDTechEx,2023).challEngES,SolutionS,and progrESS t

190、owardS dEcarboniSation of thE SElEctEd SEctorS 27Further improvements in battery technologies,paired with potential cost reductions,could see electrification become an increasingly relevant option for a wider set of use cases.Furthermore,the importance of the role of cold ironing13 as a part of port

191、 electrification efforts cannot be overstated.Some vessel types,such as tankers and bulk carriers,spend considerable time at berth and consequently,a considerable proportion of their emissions over 20%occur while they are in port(IMO,2021a).Sustainably produced,low-carbon biofuels,such as biodiesel,

192、renewable diesel,14 bio-LNG and bio-methanol can be effective short-to medium-term options for shipping.Biofuels boast high technological readiness,allowing them to be immediately harnessed as blends or drop-in fuels,requiring little to no changes in terms of operation and infrastructure.However,it

193、is crucial to acknowledge that the rapid scale-up of sustainable biomass sourcing requires careful consideration of its potential negative impacts,including land-use change and life-cycle GHG emissions.This necessitates strict controls along the entire supply chain,robust certification mechanisms an

194、d substantial policy interventions in the agriculture sector.Overall,three main barriers have limited the potential of biofuels in shipping:economics,sustainability and availability concerns.Yet,despite these challenges,biofuels are a key decarbonisation option for the sector,not only as a fuel,but

195、potentially as a source of biogenic carbon for e-fuel production.Biofuels are the cheapest non-fossil fuel alternative,while sustainability concerns can be addressed through good practices(IRENA,2022).In addition,the availability of sufficient sustainable biomass is not a hard constraint on biofuels

196、 playing an important role in decarbonising the shipping sector.IRENA suggests that the global technical potential for sustainable advanced biofuels is at least 114EJ(IRENA,2016),roughly 11times the energy demand for shipping.Current biofuel production globally is only around 4.5EJ,mostly food and f

197、eed crop-based(90%)and used mainly for road transport(OECD/FAO,2023).As road transport is trending fast towards electrification,there is an opportunity to switch automotive biofuel production towards the production of biofuels for other sectors,such as shipping and aviation.In the medium-to long-ter

198、m,e-fuels produced from green hydrogen in the form of e-methanol,e-ammonia,and e-methane could also play a significant role in the sectors decarbonisation.These fuels bring advantages.These include the fact that they can be produced with zero-carbon renewable power,and they have their potential to s

199、atisfy demand is virtually unlimited,given direct air carbon capture technologies.These fuels also come with limitations,however,and should not be perceived as“silver bullets”in sector decarbonisation.13 Cold ironing refers to the process of providing shoreside electrical power to a ship at berth wh

200、ile its main and auxiliary engines are turned off.14 Biodiesel and renewable diesel are different fuels.Biodiesel is chemically distinct from regular diesel and can only be currently used in blends without engine modifications.Renewable diesel is chemically identical to regular diesel and can be use

201、d as a drop-in fuel without any need for modification.DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G728One of the main challenges for e-methanol(CH3OH)and e-methane(CH4)as synthetic fuels,is that they need carbon for their synthesis.This means that for these e-fuels to be

202、 truly green,the carbon needs to come from sustainable sources,i.e.from biogenic sources,or captured directly from the atmosphere.Fossil-sourced carbon would make these fuels unsustainable and incompatible with net-zero goals.Potentially,they would also have even greater lifecycle emissions than con

203、ventional marine fuels(MAN ES,2023).Indeed,the cheap and sustainable sourcing of carbon should be a key consideration when discussing e-fuels,as it could become a bottleneck in their deployment and an important component of their cost.To achieve cost efficiency,cheap sources of biogenic or atmospher

204、ic carbon and green hydrogen would likely have to be near each other to prevent the high costs of transporting either one for the manufacture of e-fuels.Biogenic sources are currently the cheapest source of carbon,while the alternative is direct air carbon capture,whose prospects for cost reduction

205、are uncertain.E-ammonia(NH3),on the other hand,has the advantage that it does not require a carbon source,so it can be produced in any location as long as there is a cheap supply of low-carbon energy.However,the main challenges for ammonia as a marine fuel come from its toxicity and the operational

206、challenges it presents.Ammonia engine technologies are also still only under development.The use of ammonia as a marine fuel will require robust operational and safety standards and creates the need for new capacities and skills that can guarantee its safe handling,even though there are already stan

207、dards for its handling in the chemical industry.Source:(IRENA,2018,2021a;IRENA and AEA,2022;IRENA and Methanol Institute,2021;Ship&Bunker,2024).Note:Renewable fuel costs are production costs.VLSFO shows the highest and lowest spot prices registered between March 2021 and March 2024.50040030020010050

208、4503502501500BiomethaneBiomethanol(MSW)Biomethanol(biomass)E-methanol(Biogenic)E-methanol(DAC)E-ammoniaHVOFAMEUSD/MWhVLSFO lowVLSFO highFigure 6Cost comparison of renewable marine fuelschallEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 29Finally,an important aspect to

209、consider when discussing e-fuels is their efficiency.E-fuels require significantly more primary energy,compared to other alternatives such as direct electrification and some biofuels.The use of e-fuels should therefore preferably be limited to cases where more efficient alternatives are unfeasible.A

210、s all alternative fuel options have their own sets of challenges,a combination of renewable-based options will likely be needed to fully decarbonise the sector.The active adoption of energy efcient technologies and operational measures will be critical toreduce energy demand and CO2 emissions in the

211、 short term.Such technologies and measuresinclude shore power,improved route planning,high efciency propellers,wind assisted propulsion,waste heat recovery systems and speed optimisation,among others.Further reductions areexpected to come from changes in global trade dynamics,as other sectors transi

212、tion to net-zero.Electrification of ports could lead to short term emissions reductions through,e.g.cold ironing.Additionally,electric vessels such as ferries and coastal and river transports could playan important role in decarbonising short and inland routes.In the medium-to long-term,green hydrog

213、en-based fuels(e-fuels),such as green methanol,ammonia and methane,could play a significant role in the sectors decarbonisation.Ammonia does not require a carbon source,so it can be produced in any location with cheaprenewable power supply.In contrast,due to its toxicity,it has important operational

214、 challenges.Methanol does not have the operational challenges of ammonia,but it requires a renewablecarbon source,which makes the scalability of production more challenging.Sustainably produced biofuels are short to medium-term options for shipping.The high technological readiness of liquid biofuels

215、 produced from second-generation feedstock,as well as bio-LNG and bio-liquefied petroleum gas(LPG),allows them to be harnessed asdrop-in fuels,requiring little-to-no changes in operation and infrastructure.Figure 7Summary of decarbonisation pathways and infrastructure needs for shippingKey infrastru

216、cture needs for shipping Reinforcement of port connections to transmission and distribution grids Shore-to-ship power infrastructure Electric charging facilities for electric vessels Transport,storage and bunkering equipment for sustainable shipping fuels (e.g.bio/e-methanol and e-ammonia)Snapshot f

217、reddy/SDECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G730Tracking progressThe transition towards net-zero shipping is gaining momentum and important players in the sector,both public and private,have already taken steps in the right direction.Most notable among these is th

218、e IMO,which is responsible for regulating international shipping and which recently revised its Strategy on Reduction of GHG Emissions from Ships.The revised strategy aims for a reduction in GHG emissions from ships of at least 20%(striving for 30%)by 2030,with the goal of achieving net-zero emissio

219、ns by around 2050.In addition to this,the IMO has established energy efficiency indexes that require emissions reductions for both newly built and existing ships.This is an important step since policy can be an important if not the most important driver in the decarbonisation of the sector.The IMOs

220、initiative is expected to be complemented by a basket of measures,too,with these including a marine fuel standard and a GHG pricing mechanism,expected to enter into force by 2027(IMO,2023).Also notable is the EUs FuelEU Maritime Initiative,which aims to provide legal certainty for ship operators and

221、 fuel producers and help kick-start the large-scale production of sustainable maritime fuels.It will do this by introducing energy intensity reduction mandates,incentives for renewable fuels of non-biological origin and an obligation to use onshore power supplies,among other provisions(European Coun

222、cil,2023).At the same time,the importance of carbon pricing cannot be overstated.Net-zero fuel alternatives currently come at a considerable cost premium,with carbon pricing a key policy option in narrowing the cost gap and/or funding the deployment of clean infrastructure.For reference,over the las

223、t couple of years,the cost of alternative fuels has been between two to sixtimes higher than the cost of HFO(DNV,2024a).A good example of the potential impact of carbon pricing in closing this gap is the inclusion of shipping in the EU Emission Trading System(EUETS).Over the coming years,this scheme

224、 will make vessels sailing in European waters pay for an increasingly larger share of their emissions.When comparing biodiesel and marine gas oil(MGO)prices between 2022-2023,if the additional CO2 emissions cost for MGO featured in the EUETS had been operational,biodiesel would have been cost compet

225、itive with its fossil counterpart(Argus,2023).Similarly,policies offering financial incentive schemes for e-fuel production and direct air capture,such as the Inflation Reduction Act in the UnitedStates,can play an important role in de-risking first movers and creating initial demand for renewable f

226、uels(DOE,2023).The private sector is also taking steps,with several shipping companies establishing their own net-zero targets,and several initiatives emerging,such as the Getting to Zero Coalition.15 This has gathered 160 companies within the maritime,energy,infrastructure and finance sectors,suppo

227、rted by key governments and intergovernmental organisations(IGOs).15 See:www.globalmaritimeforum.org/getting-to-zero-coalition challEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 31The timely deployment of the necessary technology and infrastructure at ports(i.e.grid in

228、frastructure for electrification and sustainable fuel terminals),on ships and in fuel manufacturing is also important in enabling the adoption and mainstreaming of renewables-based fuels and in avoiding delays in the transition.The sector is currently experiencing a growth in orders for LNG-and meth

229、anol-powered vessels(DNV,2024a)and is also looking at ammonia as a solution for the future.These fuels all have different infrastructural needs,a fact that will have to be considered when evaluating decarbonisation strategies.The deployment of new LNG-powered vessels offers limited benefits in terms

230、 of emissions reductions compared with the current fuel mix and creates a risk of fossil technologies becoming locked-in.While LNG ships are theoretically compatible with bio-LNG or renewable e-methane,the scalability and the cost reduction potential of these options is limited.Methanol engines are

231、a mature and proven technology and ship orders are growing,particularly in the container ship segment.In October 2023,A.P.Moller-Maersk launched the first container ship powered by green methanol,the Laura Maersk(Maersk,2023a).It is expected that as many as 170 methanol-compatible ships will be on t

232、he water in the next five years(DNV,2024a).Ammonia engines,on the other hand,still need some development.Currently they are at technology readiness level 4(TRL4)technology validated in a laboratory although they are expected to reach TRL9 technology proven operationally by 2025.They could therefore

233、play a more relevant role in the medium-term,as ammonia is a carbon-free e-fuel,unlike methanol(MAN ES,2023).The decarbonisation of the sector through renewable fuels will depend on the ability to scale up renewable fuel supply(biofuels and green e-fuels)rapidly and sustainably.This must also be don

234、e without overlooking the need for sustainable and affordable sources of carbon that are biogenic or come from direct air carbon capture,while also being available at the right locations.There are also steps being taken in terms of building up the supply and demand for alternative fuels.This require

235、s considerable investment in developing fuel manufacturing projects and deploying the necessary infrastructure.The uptake of e-fuels in shipping,for example,necessarily implies an important increase in renewable power supply to produce green hydrogen as a feedstock.According to IRENAs World Energy T

236、ransitions Outlook(WETO),decarbonising shipping would require close to 60megatonnes(Mt)of green hydrogen/year,roughly equivalent to two-thirds of todays total hydrogen supply.This would require roughly 600gigawatts(GW)of electrolyser capacity and 1.2terawatts(TW)of renewable capacity(IRENA,2023a).Th

237、is would be roughly equivalent to the total global installed hydropower electrical capacity in 2022(IRENA,2024b).Attracting investments in new technologies can be challenging.Projects face bankability challenges due to uncertainties in demand,the higher costs of alternative fuels,and the sector bein

238、g highly competitive,internationally.Efforts from governments and multilateral financial institutions are needed to level the playing field as well as to finance the deployment of the necessary technology and infrastructure.DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G73

239、2The co-operation of private actors along the supply chain can also play a role in de-risking investments.A good example of this is the off-take agreement signed in 2023 between A.P.Moller-Maersk and Chinese developer Goldwing for the provision of 500 000 tonnes per year of green methanol(Maersk,202

240、3b).Such“vertically integrated”agreements ensure a stable demand for the fuel producer,facilitating the financing of the fuel supply projects,while also giving security to the shipping company by guaranteeing the required supply volumes of green fuel at predictable prices.Renewable fuels are still i

241、n their early stages of adoption and their handling and operation will likely require a completely new set of skills and procedures.These will also have to be adopted at a global scale for example,in ammonia bunkering operations.In this regard,the sector would benefit from co-operating and building

242、synergies with other sectors such as aviation,which has similar decarbonisation pathways and shares some of the same challenges.The chemical sector,too,has decades of experience in the handling of some of the chemicals that are now being used as fuels.Collaborative efforts such as green corridors ca

243、n also help demonstrate the feasibility of new technologies and accelerate their scaling up.There are multiple examples of collaborative initiatives,such as the Clean Energy Marine Hubs by Clean Energy Ministerial(CEM,2023),or the recently signed agreement between the UnitedKingdom and the UnitedSta

244、tes for the establishment of a green shipping corridor(DfT,2023).This is one of over 50 green shipping corridors that have so far been announced worldwide(DNV,2024b).2.3 AviationAviation plays a vital role in connecting people,enabling global business,facilitating international trade and tourism,and

245、 providing a means of rapid transportation.The sector is a driver of economic growth,shortening travel times and increasing global interconnectedness.One of the main challenges faced by aviation,however,is in both providing its social and economic benefits while also increasing its environmental res

246、ponsibility.As one of the most carbon-intensive transport modes,aviation is a significant contributor to global GHG emissions and climate change.It is worth noting that the sector is also responsible for non-CO2 emissions,i.e.other gases and aerosol particles which affect the atmospheric composition

247、 and affect cloudiness,adding to the impact of the sectors CO2 emissions(Lee,2018).In recent decades,demand for aviation services has steadily grown and could double by 2050,compared to 2022 levels(Graver,2022;IATA,2023).Therefore,there is a need to rapidly deploy decarbonisation solutions.challEngE

248、S,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 33Emissions and energy useIn 2022,the energy consumption of the global aviation sector reached 11 EJ.This equates to 10%of the worlds transport-related energy consumption and 3%of total global energy consumption(IEA,2023a).This

249、 energy demand was met nearly exclusively by fossil fuels.Only 450 million litres of sustainable aviation fuels(SAF)were consumed that year,equivalent to 0.1%of global aviation fuel consumption(IATA,2022).Dependency on fossil fuels results in aviation contributing significantly to the worlds CO2 emi

250、ssions and climate change.CO2 emissions from aviation in 2022 reached 0.8 Gt,equivalent to between 2%and 3%of global emissions and 10%of all transport related emissions(IEA,2023a).Growth in aviation emissions has been also continuous,but it has been partially offset by substantial efficiency improve

251、ments.As shown in Figure 8 below,these improvements have resulted in as much as 11 Gt of CO2in emissions reductions since 1990(ATAG,2021).In addition to carbon emissions,aviation also contributes to global warming through the formation of contrails.Due to the mass and volume limitations of aircraft,

252、aviation depends on highly energy-dense fuels.There are sustainable fuel alternatives,but these come with a cost premium.The limited choice of usable fuels and the immaturity of alternative aircraft technologies,such as electric or hydrogen-powered aircraft,therefore limit the decarbonisation pathwa

253、ys available to the sector.Source:(ATAG,2021).Emissions reductions already achieved:over 11 Gt of CO2 avoided throughinvestment in technology andoperational improvements since 1990Carbon-neutralgrowthRequiredemissionsreductionsFROZEN 1990 EFFICIENCY2050emissionswithoutadditionaleforts:2 000 MtNet-ze

254、roCO2 emissions5 200 Mt4 0005 0006 0003 0002 0001 000002020203020402050CO2(million tonnes)Figure 8Historical and projected CO2 emissions of the aviation sector,1990 2050DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G734Decarbonisation pathwaysOne pathway is the

255、continued deployment of technological and operational energy efficiency improvement measures.Indeed,while the aviation sector has made significant progress in deploying increasingly efficient airframes and engines,there is still potential for further improvement.The International Civil Aviation Orga

256、nisation(ICAO)long-term aspirational goal aims for a 2%increase in fuel efficiency annually until 2050.This is higher than the average historically observed and other projected improvements of just 1.5%per year(ICAO,2022).According to IRENAs 1.5C scenario,demand reduction and energy efficiency impro

257、vement are an important part of the sectors decarbonisation efforts.These measures could account for roughly half of the sectors emission reductions by 205016(IRENA,2023a).Further reductions could come from modal shifts in short-distance air travel for example,replacing short flights with trains,whi

258、ch are much less carbon intensive(European Environment Agency,2023).Undoubtedly the most technologically straightforward pathway to decarbonise the sector,however,is the use of advanced biofuels,namely biojet,given the maturity of the technology.Biojet can be used as a drop-in fuel on existing and f

259、uture aircraft,making it a practical and immediately implementable option.Long-term bioenergy potential is not a constraint for the transition of the sector,either.IRENA suggests that the global technical potential for sustainable advanced biofuels is at least 114EJ(IRENA,2016),or roughly eight time

260、s the energy demand for aviation.Current global biofuel production is only around 4.5EJ,however,and is mostly food and feed crop-based(90%)and used mainly for road transport(OECD/FAO,2023).The main challenge with biofuel is first,its higher cost compared to conventional jet fuel,and second,the need

261、to scale up its supply sustainably.Indeed,the rapid scale-up of sustainable biomass is complex and cannot be achieved without careful consideration of its potential negative impacts,particularly in terms of land use change and life cycle GHG emissions.This needs strict controls along the entire supp

262、ly chain,robust certification mechanisms and substantial policy interventions in the agriculture sector.At the same time,the increasing electrification of road transport could allow redirecting biofuel production capacity towards other sectors,such as aviation and shipping.Another option is the adop

263、tion of synthetic fuels produced from green hydrogen that produced from electrolysed water using renewable electricity.This can then be combined with a renewable source of carbon to produce a hydrocarbon fuel.The two options being currently considered are green hydrogen and e-kerosene.Yet,while hydr

264、ogen could eliminate exhaust emissions from aviation,hydrogen aircraft technology for large passenger or cargo transport does not exist yet.This technology is also not expected to reach commercial maturity within a timeframe compatible with making a material impact on carbon neutrality by mid-centur

265、y.A fundamental issue revolves around the low volumetric energy density of hydrogen,which would require a fundamental redesign of airframes as well as operational procedures and safety standards.Furthermore,there is no hydrogen refuelling infrastructure in place.16 IRENAs 1.5C scenario does not aim

266、for net-zero in aviation alone,but rather across all energy systems.Therefore,emissions in aviation are not eliminated in this scenario,with residual emissions being offset by negative emissions in other sectors.challEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 35E-ke

267、rosene,on the other hand,is chemically identical to its fossil counterpart and could be used in existing aircraft.The use of e-kerosene opens the door for deep emissions reductions.However,the fact that the e-kerosene molecule contains carbon adds a layer of complexity.For e-kerosene to be an effect

268、ive decarbonisation solution,it would have to be low-carbon and this carbon would need to come from a sustainable source,i.e.from biogenic sources such as bioenergy with carbon capture or captured directly from the atmosphere.The need to build a sustainable supply chain for carbon is a major challen

269、ge,particularly given that to achieve cost efficiency,cheap renewable electricity for hydrogen production and a sustainable(and scalable)carbon source would need to be available.Biofuels and e-fuels could account for the remaining half of the necessary CO2 reductions needed by 2050,as per IRENAs 1.5

270、C scenario.Finally,electric propulsion is another technology pathway that should be considered for aviation.In the past,this has had limited potential as a decarbonisation solution due to the limited energy density of commercially available batteries.However,there has been remarkable progress in bat

271、tery technologies over the last few years.Breakthroughs in energy density,with some batteries reaching 500Wh/kg,could open the door to their application in electric or hybrid small aircraft and short-haul flights(CATL,2023).Source:(IRENA,2021b;WEF,2020).Note:Jet fuel shows the highest and lowest pri

272、ces registered between January 2020 and March 2024.Adv.=advanced;AtJ=alcohol-to-jet;GtL=Gas-to-liquid;BtL=biomass to liquids;FT=Fischer Tropsch;Cat.Hydro.=Catalytic hydrothermolysis;HTL=Hydrothermal liquefaction;Pyr.=pyrolysis;PtL=Power-to-liquid.6 0005 0004 0003 0002 0001 0000Bio-GtLBtLCat.HydroGas

273、ificationFTHEFA/HVOHTLPyr./Bio-oil/UpgradingPtLAtJAdv.FermentationUSD/tonJet fuel lowJet fuel highFigure 9Production cost comparison of sustainable aviation fuelsDECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G736Electric propulsion also offers potential advantages over jet

274、 engines in areas such as higher efficiency,lower mechanical complexity and maintenance costs.Yet,this pathway is not without its challenges.These include the need to develop and certify new aircraft concepts,in addition to the need for further research and development in battery technologies.This i

275、s necessary to make them viable for flight as well as ground operations.These challenges also limit the decarbonisation potential of this technological pathway,given that new aircraft concepts can take as long as a decade to be developed and certified(FAA,2023).The continued improvement of energy ef

276、ciency measures and technologies is critical.Improved aerodynamics,weight reduction and the integration of more efcient engines,for example,can reduce energy demand and thus CO2 emissions.Further reductions could comefrom a modal shift in short distance travel,likely to rail transport.Direct electri

277、fication,in the form of electric or hybrid electric aircraft could play an importantrole in reducing aviation emissions for short-haul aviation in the medium-to long-term.Synthetic fuels can also play a significant role in the decarbonisation of aviation.This can be achieved in the medium term throu

278、gh e-kerosene and in the long term,possibly by green hydrogen.E-kerosene requires a renewable carbon source,which makes the scalability of fuel production more challenging.Sustainable,low-carbon biofuels are the most technologically straightforward pathwayto decarbonise aviation.Biojet can be used a

279、s a drop-in fuel on existing and future aircraft.Their scale-up will require major policy developments to ensure sustainability.Figure 10Summary of decarbonisation pathways and infrastructure needs for aviationKey infrastructure needs for aviation Adaptations in fuel supply infrastructure to integra

280、te SAF.Reinforcement of airport connections to transmission and distribution grids Charging infrastructure for ground operation vehicles and electric aircraft In the long-term,should hydrogen-powered aircraft become a reality,hydrogen transport,storage and fuelling infrastructure would be needed.Sna

281、pshot freddy/SchallEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 37Tracking progressThe aviation sectors energy transition is lagging,as evidenced by the negligible,0.1%share taken by SAF in its fuel consumption(IATA,2022).Despite this,there are increasing signals with

282、in the sector of a willingness to work towards climate neutrality.According to the ICAO,by the first quarter of 2024 there were 30 facilities producing sustainable aviation fuels worldwide,with a potential total output capacity of 8.5billion litres of SAF per year(ICAO,2024).Policies will be critica

283、l to build momentum and trigger action towards the decarbonisation of the sector.In this regard,the ICAO and its members have taken steps in the right direction.These include:the development of the Carbon Offsetting and Reduction Scheme for International Aviation(CORSIA)in 2016;the adoption of a lon

284、g-term aspirational goal(LTAG)for international aviation in 2022,which aims at net-zero carbon emissions by 2050;and the adoption of the ICAO Global Framework for Sustainable Aviation Fuels,Lower Carbon Aviation Fuels and other Aviation Cleaner Energies(ICAO,2023b).The private sector has also seen s

285、ome commitments made.These include the Air Transport Action Group(ATAG),which includes representatives of major aviation industry associations and of the largest aircraft and engine makers.ATAG has made a commitment to reach net zero by 2050(ATAG,2023).Currently,the industry mostly relies on carbon

286、offsetting as a mechanism to contribute towards global climate goals.However,offsets do not actually decarbonise the sectors operations and in most cases they do not even deliver net emissions reductions(Probst et al.,2023).Renewable fuel alternatives currently come at a considerable cost premium.Ca

287、rbon pricing policies,such as the EU ETS,can play a central role in accelerating the adoption of such alternatives,however,by narrowing the cost gap with fossil fuels and incentivising the deployment of clean infrastructure.Yet,while aviation emissions have been included in the EU ETS since 2012,the

288、 scheme only covers intra-European flights.17 In 2022,the EU also agreed to phase out free allowances by 2026,which was a major shortcoming in the original rules governing aviation in the EU ETS and which will see obligated parties pay more(EC,2022).Together with carbon pricing,policies such as ReFu

289、elEU18 can also accelerate adoption not only by enforcing the initial uptake of sustainable aviation fuels,but also by sending a longer-term signal to the market regarding the volume of fuels that will be needed.ReFuelEU mandates a gradual increase in the minimum share of SAF in fuel supply and obli

290、ges airports to guarantee the necessary SAF infrastructure.With such signals,investors in fuel production assets can have more certainty about the demand they can expect from aviation.17 From 1 January 2024,it also covers non-domestic flights to and from outermost regions of the Union that were prev

291、iously exempted(EC,2023c).18 See:www.consilium.europa.eu/en/press/press-releases/2023/10/09/refueleu-aviation-initiative-council-adopts-new-law-to-decarbonise-the-aviation-sector/DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G738Financial incentives can also help accelerat

292、e the scale-up of biofuels and e-fuels,de-risking first movers and levelling the competitive playing field.A good example of these is the Inflation Reduction Act19 in the UnitedStates,which offers tax credits for SAF production and for low-carbon hydrogen production.Large investments will be needed

293、to develop the SAF supply chain.The sector is already experiencing some movement in this regard,with some of the largest players in the sector including aircraft manufacturers and airlines making investments and partnerships in SAF production.Examples of this include the memorandum of understanding

294、signed between AirFrance-KLM and Total Energies for the provision of 800 000tonnes of SAF over a 10-year period.This is more than three times the amount of SAF the whole industry consumed in 2022(Total Energies,2022).Other players,such as Airbus,have created partnerships with fuel manufacturers to f

295、oster sustainable aviation fuel production(Airbus,2023).Overall,as of 2023 forty-fivee-kerosene projects and twentypilot projects had been identified in Europe.However,none had yet reached a financial decision stage(T&E,2024).Indeed,despite various announcements and statements indicating a commitmen

296、t to decarbonisation within the sector,actual deployment of SAF remains limited.Some airlines offer their clients the possibility of offsetting their emissions,and more recently,to pay for the use of SAF.These measures,however,depend on the customers willingness to pay and do not require any climate

297、 commitment from the airlines;they simply transfer the environmental responsibility to the customer.Furthermore,airline pricing models can be a disincentive for emission reductions.Direct flights,for example,generally emit less CO2 than connecting flights(Debbage and Debbage,2019),but it is sometime

298、s cheaper to take a connecting flight than a direct flight.A combination of increased ambition,real commitments and structural changes across the sector could,nonetheless,really accelerate the transition.2.4 Iron and steelSteel is an indispensable material in our modern world.It is widely used in in

299、frastructure,buildings,transportation vehicles,home appliances,medical equipment and in many other areas that support society and its well-being.Steels strength,durability,versatility,and recyclability make it suitable for this vast array of applications.Demand for steel closely follows the developm

300、ent of an economy,particularly in the early stages of industrialisation.Furthermore,steel plays a vital role in the energy transition,as it is used in several renewable technologies,such as EVs,wind turbines,and solar photovoltaic(PV)structures(IRENA,2023c).19 See:www.whitehouse.gov/cleanenergy/infl

301、ation-reduction-act-guidebook/#:text=The%20Inflation%20Reduction%20Act%20specifies,mode%20or%20condition%2C%20low%20or challEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 39Emissions and energy useSteel production has been increasing consistently over time.In absolute t

302、erms,the production of steel rose almost tenfold from 190milliontonnes in 1950 to almost 1.85billiontonnes in 2023(IRENA,2023c;WSA,2024).This significant rise in steel production has also led to an increase in CO2 emissions from the sector.Currently,the production of steel is carbon intensive,relyin

303、g primarily on fossil fuels,both for energy and as reductants in the processing of iron ore.For every tonne of steel produced in 2022,approximately 1.4tonnes of CO were emitted into the atmosphere.That same year,the iron and steel sector alone was responsible for about 8%of global energy and process

304、-related CO2 emissions.In absolute terms,this was equivalent to 2.8Gt of direct CO2 emissions(IEA,2023a).Steel can be produced via primary or secondary routes(Figure11).Primary steel production involves two steps:ironmaking,where iron ore is reduced to pig iron in a blast furnace(BF),or sponge iron

305、is produced via direct reduction;20 and steelmaking,where the iron is processed in a basic oxygen furnace(BOF)or an electric arc furnace(EAF),depending on the type of iron input.In secondary steel production,steel scrap is reclaimed and re-melted in an EAF,without the need for a new iron ore reducti

306、on process.20 Direct reduction refers to the group of processes for making iron from iron ore in solid state.This is done without exceeding the melting temperature of iron by using carbon monoxide and hydrogen derived from natural gas or coal,so no blast furnace is needed(IRENA,2020).Source:(IRENA,2

307、023d).Note:BF=blast furnace;BOF=basic oxygen furnace;DRI=direct reduced iron;EAF=electric arc furnace.BF-BOFrouteDRI-EAFrouteSecondaryproduction route IronreductionBlastFurnaceIron oreGas/Coal/OilElectricityShaftFurnaceGas/CoalSteelproductionBOFScrapsteelEAFElectricityEAFCrudesteel Crudesteel Crudes

308、teel Finished steel products DownstreamprocessingElectricityIron oreOxygenScrap steel ElectricityScrapsteelFigure 11Traditional pathways for steel productionDECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G740The BF-BOF is currently the predominant production route,accountin

309、g for about 72%of global steel production(Figure12).This route is also the most energy and emission-intensive,as it relies on coal,coke and other coke products as the primary reductant agent and energy source.On the other hand,secondary steel production based on scrap,which accounts today for about

310、22%of total production,is the least energy and emission-intensive production route,as it mostly relies on electricity.The DRI-EAF route is more energy and emission-intensive than the scrap-based route,due to its reliance on natural gas for iron reduction.It is worth noting that while scrap-EAF only

311、accounts for 22%of all production,recycled scrap accounts for roughly 30%of the total metallic raw material inputs for global steel production(IEA,2020;WSA,2023a,2023b).Decarbonisation pathwaysLargely driven by the growth of emerging economies,demand for steel is expected to rise from about 1 850mil

312、lion tonnes(Mt)per year today to about 2 500Mt per year by 2050.It is therefore paramount to transition away from current fossil fuel-dependant production routes towards renewable-based production pathways(IRENA,2023c).IRENAs 1.5C scenario highlights the need for a combination of strategies to decar

313、bonise the iron and steel sector,including:increased scrap recycling;process efficiency;material efficiency;and renewable-based primary steel production,mainly using green hydrogen(IRENA,2023a).Source:(IEA,2020;WSA,2023a,2023b).Note:DRI-EAF is natural gas-based and DRI-EAF production values are esti

314、mated.100%90%80%70%60%50%40%30%20%10%2.52.01.50.51.00%0BF-BOFDRI-EAF*Scrap EAFShare of ProductiontEmission Intensity(t CO2/t crude steel)Share of ProductionEmission IntensityFigure 12Share of production routes and their estimated emissions intensitieschallEngES,SolutionS,and progrESS towardS dEcarbo

315、niSation of thE SElEctEd SEctorS 41Direct electrification using renewable electricity is set to play a key role in decarbonising the sector.It will do this by increasing the share of steel produced through the secondary route mentioned above.When powered by renewable electricity,steel can be produce

316、d via the EAF method with near-zero emissions.At the same time,scrap availability is expected to increase along with historic steel production levels and many steel products reaching their end-of-life.Globally,steel scrap availability is therefore expected to increase from between 770Mt per year and

317、 870Mt per year currently to between 1 250Mt per year and 1 550Mt per year by 2050(Figure13).Scrap-EAF production already accounts for 32%of the total steel decarbonisation projects announced(BNEF,2024a).The process of collecting and sorting can be expensive and time-consuming,however,and may limit

318、the use of scrap.In addition,impurities in steel scrap,such as copper and tin,can limit its usability for certain applications.These contaminants can come from previous-use cases and improper scrap management practices(IRENA,2023c).In the future,direct electrification could also play a role in the d

319、ecarbonisation of primary steel production.It could do this by using high-or low-temperature electrolysis to reduce iron ore.However,these technologies are still in their early stages.The Boston Metal Group is one of the companies pursuing this route,aiming to have a commercial plant deployed by 202

320、6.Another initiative,the SIDERWIN consortium has demonstrated the feasibility of iron production via electrolysis at 110C(IRENA,2023c).Source:(IRENA,2023d).MtGlobal steel demandScrap available for recyclingRange of estimationsShare of scrap as metallic input0%10%20%30%40%50%60%70%80%90%100%05001 000

321、1 5002 0002 5003 000202020302050%Figure 13Global steel demand and scrap availability,2020-2050DECARBONISING HARD-TO-ABATE SECTORS WITH RENEWABLES:PERSPECTIVES FOR THE G742Material efficiency21 strategies can have a substantial impact in reducing global steel demand.According to IRENAs 1.5C Scenario,

322、the adoption of such measures could reduce global steel demand by 7%by 2030 and 15%by 2050(IRENA,2023a).Apart from reducing direct material demand,these strategies can also bring various systemic environmental and economic benefits beyond the steel sector.22 Some challenges exist in the widespread a

323、doption of such strategies,however.These include:the need for technical changes happening over several years;regulatory restrictions that may limit the use of alternative materials;the need for additional investments in new manufacturing technologies and processes;and the need for specially skilled

324、labour with technical expertise to adapt to new,evolving measures(IRENA,2023c).Yet,owing to the increasing availability of scrap and the demand reductions that can come from the widespread adoption of material efficiency measures,by 2050,as much as half of global steel demand could be satisfied thro

325、ugh secondary steel production based on scrap.However,to completely decarbonise the sector,the remaining half of global steel production,which relies on the primary route,would also have to transition away from fossil fuels towards renewable-based alternatives.One promising approach is the use of hy

326、drogen-based direct iron reduction(DRI).23 This can reduce emissions by around 95%,as showcased by the worlds first batch of renewable-based primary steel,delivered by the HYBRIT plant in Sweden in 2021(Reuters,2021).Hydrogen-based DRI is close to commercial maturity and becoming widely accepted as

327、an alternative technology within the industry,with over 57 projects,or 40%,of the project pipeline announced by 2023(BNEF,2024a).By 2030,62Mt of steel per year from Hydrogen-based DRI could materialise(BNEF,2024a).While the cost differential between conventional and green crude steel produced via hy

328、drogen-based DRI is substantial,the cost impact on some higher added-value end products can be relatively low.For instance,an increase of 40%to 70%in the per tonne cost of steel translates into less than a 1%increase in an average passenger cars overall cost,while the cost increase for buildings is

329、around 2%(Sandbag Climate Campaign ASBL,2024).The widescale adoption of hydrogen-based steel faces several challenges,however.These include:a requirement for high-grade iron ore;access to sufficient volumes of low-cost renewable electricity;24 a dependable supply of green hydrogen and associated inf

330、rastructure;and geographical location for hydrogen production and storage facilities(IRENA,2023c).21 Material efficiency refers to decreasing the amount of a material needed to produce a product and maximising its value.For steel,this could include producing lighter steel products and structures,ref

331、urbishing and reusing steel products,and redesigning products with alternative materials when justified,based on life cycle analysis.22 For example,the use of high-strength steel in vehicles can make them lighter,reducing their fuel consumption and emissions,while helping them maintain service effic

332、iency.This is particularly true for EVs,which have smaller carbon footprints(IRENA,2023c).23DRI is the chemical removal(reduction)of oxygen from iron ore in its solid form.24 Producing 1 Mt/year of hydrogen requires around 10 GW of electrolyser capacity and 20 GW of renewable power for electricity(I

333、RENA,2023c).challEngES,SolutionS,and progrESS towardS dEcarboniSation of thE SElEctEd SEctorS 43Tracking progressAs the political momentum towards addressing climate change grows,key industrial sectors like iron and steel are receiving increased attention.By the end of 2021,more than 90%of the worlds steel capacity and production came from countries committed to achieving net-zero emissions by mid