Life cycle carbon footprint of battery electric bus: coupling effects of mileage, energy mix and recycling processes

Abstract

With the global push toward carbon neutrality, reducing greenhouse gas emissions in the transportation sector has become increasingly urgent. Electric buses represent a promising solution; however, their full life cycle carbon footprint remains underexplored. This study aims to address this gap by quantifying and comparing the life cycle carbon emissions of pure electric buses. A life cycle assessment (LCA) approach is applied to evaluate emissions across the production, usage, and recycling stages. Scenario analyses are conducted to assess the impact of carbon fiber reinforced polymer (CFRP) as a material substitute, variations in electricity generation mix, coal consumption rates, and the extent of recycled material utilization. Results show that buses using nickel manganese cobalt (NMC) battery type C have the lowest life cycle emissions at 55,814.89 kg CO₂-eq, while those with lithium iron phosphate (LFP) battery type A have the highest, reaching 59,364.10 kg CO₂-eq. During the production stage, the primary emission sources are the body, chassis, battery system, and electricity consumption. Substituting steel and aluminum with CFRP increases production emissions by up to 108.6%. However, in the operational phase, CFRP significantly reduces bus weight by 41.99% and cuts operational carbon emissions by 36.49%. In the recycling stage, NMC battery type C yields the highest emission reduction, achieving 14,943.86 kg CO₂-eq, mainly due to the recovery of nickel and lithium compounds. These findings offer valuable insights for optimizing material choices, energy structures, and recycling strategies to support the low-carbon development of electric buses.

Keywords

Lithium-ion battery / battery power bus / life cycle assessment / carbon footprint / electricity mix / recycling process

References

[1] Zhu M,Li J.Electric vehicle battery capacity allocation and recycling with downstream competition.Eur J Oper Res2020;283:365-79

[2] Yu X,Ji L. Analysis on carbon emission reduction potential of electric vehicles in China under goal of carbon neutrality and carbon peaking. Smart. Power. 2024, 52, 25-31+39. Available from: http://zhdlqk.sn.sgcc.com.cn:19001/#/digest?ArticleID=5864 [Last accessed on 23 July 2025]

[3] Shi Y,Yu Z.Energy saving and emission reduction benefits analysis and environmental impact assessment of electric vehicles throughout their entire lifecycle. Resour Ind 2021;23:100-9.

[4] European Commission. A European strategy for low-emission mobility. Brussels, Belgium: 2016. Available from: https://ec.europa.eu/commission/presscorner/detail/nl/memo_16_2497 [Last accessed on 23 July 2025]

[5] Ministry of Industry and Information Technology of the People’s Republic of China industrial green development plan (2016-2020). Energy saving in non-ferrous metallurgy 2016:1-7. Available from: https://www.miit.gov.cn/jgsj/jns/wjfb/art/2020/art_d66bb56744d9433d827bdb571de9a250.html [Last accessed on 25 July 2025]

[6] Huang W. Life cycle analysis of vehicle biogas for city bus. J. Transp. Syst. Eng. Inf. Technol. 2016, 16, 44-8. Available from: http://www.tseit.org.cn/CN/Y2016/V16/I2/44 [Last accessed on 25 July 2025].

[7] Arribas-ibar M,Brem A.The risk of dissolution of sustainable innovation ecosystems in times of crisis: the electric vehicle during the COVID-19 pandemic.Sustainability2021;13:1319

[8] Deliali A,Oliver J,Godri Pollitt KJ.Transitioning to zero-emission bus fleets: state of practice of implementations in the United States.Transp Rev2021;41:164-91

[9] Waisman H,Rogelj J.Key technological enablers for ambitious climate goals: insights from the IPCC special report on global warming of 1.5 °C.Environ Res Lett2019;14:111001

[10] Cusenza MA,Ardente F,Di Persio F.Energy and environmental assessment of a traction lithium-ion battery pack for plug-in hybrid electric vehicles.J Clean Prod2019;215:634-49 PMCID:PMC6472661

[11] Lopez S,Lizundia E.Comparative life cycle assessment of high performance lithium-sulfur battery cathodes.J Clean Prod2021;282:124528 PMCID:PMC7537670

[12] Bibra EM,Dhir S. Global EV outlook 2022: securing supplies for an electric future. 2022. Available from: https://trid.trb.org/View/2005689 [Last accessed on 23 July 2025]

[13] Zeng X,Abd El-hady D.Commercialization of lithium battery technologies for electric vehicles.Adv Energy Mater2019;9:1900161

[14] Filote C,Raboaca MS.Environmental impact assessment of green energy systems for power supply of electric vehicle charging station.Int J Energy Res2020;44:10471-94

[15] Thorne R,Figenbaum E,Müller DB.Estimating stocks and flows of electric passenger vehicle batteries in the Norwegian fleet from 2011 to 2030.J Ind Ecol2021;25:1529-42

[16] Knobloch F,Lam A.Net emission reductions from electric cars and heat pumps in 59 world regions over time.Nat Sustain2020;3:437-47 PMCID:PMC7308170

[17] Feng T,Li Q,Liang W.Life cycle assessment of lithium nickel cobalt manganese oxide batteries and lithium iron phosphate batteries for electric vehicles in China.J Energy Storage2022;52:104767

[18] Degen F,Kampker A.Comparative life cycle assessment of lithium-ion, sodium-ion, and solid-state battery cells for electric vehicles.J Ind Ecol2025;29:113-28

[19] Li Y,Feng T. Environmental influence evaluation of the fuel full life cycle of city buses with different energy sources based on GREET software. Bus. Technol. Res. 2022, 44, 52-5. Available from: https://d.wanfangdata.com.cn/periodical/kcjsyyj202201016 [Last accessed on 23 July 2025].

[20] Pan Y.Analysis and estimation of emission characteristics of new energy buses based on multi-source data. Southeast University, 2020.

[21] Golkaram M,Yildiran A.Future options and their impact on the life cycle assessment and life cycle costing of segment c/d passenger vehicles. Rosearch Square 2024.

[22] Zhao C,Alquaity ABS.Solutions for decarbonising urban bus transport: a life cycle case study in Saudi Arabia.Commun Eng2024;3:238

[23] Ankathi S,Lu Z.Well-to-wheels analysis of greenhouse gas emissions for passenger vehicles in Middle East and North Africa.J Ind Ecol2024;28:800-12

[24] Zhang S,Liu H.Real-world fuel consumption and CO₂ emissions of urban public buses in Beijing.Appl Energy2014;113:1645-55

[25] Takahashi R,Noda H.Estimating the dominant life phase concerning the effects of battery degradation on CO₂ emissions by repetitive cycle applications: case study of an industrial battery system installed in an electric bus.Energies2023;16:1508

[26] Tintelecan A,Marțiș C.Literature review - electric vehicles life cycle assessment.2020 ELEKTROIEEE,2020; pp. 1-6

[27] Zhang X,Fan E.Toward sustainable and systematic recycling of spent rechargeable batteries.Chem Soc Rev2018;47:7239-302

[28] Walvekar H,Sripad S.Implications of the electric vehicle manufacturers’ decision to mass adopt lithium-iron phosphate batteries.IEEE Access2022;10:63834-43

[29] Chen Z,Li H.An efficient regrouping method of retired lithium-ion iron phosphate batteries based on incremental capacity curve feature extraction for echelon utilization.J Energy Storage2022;56:105917

[30] Penisa XN,Pascasio JDA,Schmidt O.Projecting the price of lithium-ion NMC battery packs using a multifactor learning curve model.Energies2020;13:5276

[31] Tolomeo R,Adami R.Application of life cycle assessment to lithium ion batteries in the automotive sector.Sustainability2020;12:4628

[32] Wu H,Yu Y,Wang L.Superior “green” electrode materials for secondary batteries: through the footprint family indicators to analyze their environmental friendliness.Environ Sci Pollut Res2019;26:36538-57

[33] Accardo A,Musa ML.Life cycle assessment of an NMC Battery for application to electric light-duty commercial vehicles and comparison with a sodium-nickel-chloride battery.Appl Sci2021;11:1160

[34] Petrauskienė K,Dvarionienė J.Comparative environmental life cycle assessment of electric and conventional vehicles in Lithuania.J Clean Prod2020;246:119042

[35] Liu J.Research on life cycle assessment of hydrogen fuel cell vehicles. Xi’an: Chang’an University, 2020.

[36] Liu K.Life cycle assessment of driving motor on electric vehicle.J Environ Sci2016;36:3456-63

[37] Evangelisti S,Brett DJ.Life cycle assessment of a polymer electrolyte membrane fuel cell system for passenger vehicles.J Clean Prod2017;142:4339-55

[38] Liu W,Liu Y,Cheng H.Life cycle assessment and energy intensity of CFRP recycling using supercritical N-butanol.J Mater Cycles Waste Manag2021;23:1303-19

[39] Zackrisson M. Life cycle assessment of long life lithium electrode for electric vehicle batteries:cells for Leaf, Tesla and Volvo bus. Swerea IVF Uppdragsrapporter, Swerea IVF AB, 2017: 56. Available from: https://ri.diva-portal.org/smash/record.jsf?pid=diva2%3A1131667&dswid=-5226 [Last accessed on 25 July 2025]

[40] Que T. Carbon capture and storage technology helps achieve carbon neutrality goals. China Soc. Sci. J. 2022, 006. Available from: https://epaper.csstoday.net/epaper/read.do?m=i&iid=6413&eid=45124&sid=208935&idate=12_2022-10-25_A06 [Last accessed on 23 July 2025]

[41] Liu S,Yu S,Zhang T.Electric power supply structure transformation model of China for peaking carbon dioxide emissions and achieving carbon neutrality.Energy Rep2022;8:541-8

[42] Ren S.Analysis of vehicle scrap recycling.Mech Res Appl2015;28:197-199+204

[43] Ruan R,Wang D. Life cycle assessment of biological copper extraction and pyrometallurgical copper refining processes. Multipurp. Util. Miner. Resour. 2010, 6, 33-7. Available from: https://kns.cnki.net/kcms2/article/abstract?v=5ykJdPmCibK_Yr-c9kdTPVX9-1COKWA5Cm9yuoRC0FQBOCMAKVBp_8YuJaYFFJffp4bS-arrMRJkN8ejbK7s-gbEpcYe-cS6Zfq9Jsz9IFYM1T_yP3mgNlYAzJLdDiVza4mnSPKI-YANCQpd3bwS5ryttiMfhPwK2AAmd_Zog8NSYj-skM6cQw==&uniplatform=NZKPT&language=CHS [Last accessed on 23 July 2025]

[44] Zhang B. Energy consumption in casting production. Modern. Cast. Iron. 2006, 26, 58-60. Available from: https://kns.cnki.net/kcms2/article/abstract?v=d24vdHNzaZhyahlYi_qnS92DeTtyOEiAKeeUuaDaY2Dk3K1JmELr09X0rxoWx3Pql68YnJsqm4KmaijtwquK87XzZHg1XhSoJ5rAM1PwfT4V1EwPVc95o8qQDwx8Ryy2nRQ17QWhalQMokneT71Il2EBHzx4X8vE9v6NUBCFkq0=&uniplatform=NZKPT [Last accessed on 23 July 2025]

[45] Chen Y,Liu J.Life cycle assessment of fuel cell vehicles considering the detailed vehicle components: comparison and scenario analysis in China based on different hydrogen production schemes.Energies2019;12:3031

[46] Natarajan S.An urgent call to spent LIB recycling: whys and wherefores for graphite recovery.Adv Energy Mater2020;10:2002238

[47] Wang Z.Potential and life cycle assessment of recycling and utilization of power batteries for new energy vehicles. Beijing: Tsinghua University, 2018.

[48] Liu K,Zhang Q.A perspective on the recovery mechanisms of spent lithium iron phosphate cathode materials in different oxidation environments.J Hazard Mater2023;445:130502

[49] James SL,Bolm C.Mechanochemistry: opportunities for new and cleaner synthesis.Chem Soc Rev2012;41:413-47

[50] Takacs L.The historical development of mechanochemistry.Chem Soc Rev2013;42:7649-59

[51] Zhang Y,Yang X.New progress in research on recycling technology of waste ternary lithium-ion batteries.Chem Prog2020;39:2828-40

[52] Xie Y,Ou Y. Environmental impact assessment of recycling waste traction battery. Inorg. Salt. Ind. 2015, 47, 43-46+61. Available from: https://www.wjygy.com.cn/CN/Y2015/V47/I4/43?utm_source=chatgpt.com [Last accessed on 23 July 2025]

[53] Li K.Research on the recovery technology of valuable metals in waste ternary lithium battery cathode materials. Beijing University of Chemical Technology, 2022.

[54] Jiang S,Zhang L,Wu H.Environmental impacts of hydrometallurgical recycling and reusing for manufacturing of lithium-ion traction batteries in China.Sci Total Environ2022;811:152224

[55] Ghosh T,De Kleine R,Bakshi BR.Life cycle energy and greenhouse gas emissions implications of using carbon fiber reinforced polymers in automotive components: Front subframe case study.Sustain Mater Technol2021;28:e00263

[56] Koffler C.Life cycle assessment of automotive lightweighting through polymers under US boundary conditions.Int J Life Cycle Assess2014;19:538-45

[57] Kumanan A,Narayanan K.In: Chakrabarti A, Poovaiah R, Bokil P, Kant V, editors. Design for Tomorrow-Volume 3. Singapore: Springer; 2021. pp. 263-72.Lightweighting in electric vehicles: review of the design strategies based on patents and publications.

[58] Ebrahimi S.Manufacturing sustainability: Institutional theory and life cycle thinking.J Clean Prod2021;298:126787

[59] Czerwinski F.Current trends in automotive lightweighting strategies and materials.Materials2021;14:6631 PMCID:PMC8588011