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The role of transport electrification in global climate change mitigation scenarios

The role of transport electrification in global climate change mitigation scenarios Any further distribution of this work must maintain Electrification is widely considered an attractive solution for reducing the oil dependency and attribution to the author(s) and the title of environmental impact of road transportation. Many countries have been establishing increasingly the work, journal citation stringent and ambitious targets in support of transport electrification. We conducted scenario and DOI. simulations to depict the role of transport electrification in climate change mitigation and how the transport sector would interact with the energy-supply sector. The results showed that transport electrification without the replacement of fossil-fuel power plants leads to the unfortunate result of increasing emissions instead of achieving a low-carbon transition. While transport electrification alone would not contribute to climate change mitigation, it is interesting to note that switching to electrified road transport under the sustainable shared socioeconomic pathways permitted an optimistic outlook for a low-carbon transition, even in the absence of a decarbonized power sector. Another interesting finding was that the stringent penetration of electric vehicles can reduce the mitigation cost generated by the 2 °C climate stabilization target, implying a positive impact for transport policies on the economic system. With technological innovations such as electrified road transport, climate change mitigation does not have to occur at the expense of economic growth. Because a transport electrification policy closely interacts with energy and economic systems, transport planners, economists, and energy policymakers need to work together to propose policy schemes that consider a cross-sectoral balance for a green sustainable future. 1. Introduction electricity, offer an alternative to conventional fossil-fuel technologies, and switching to electricity for road trans- The transport sector accounts for approximately a port has been proposed as a significant way to reduce quarter of global greenhouse gas (GHG) emissions and is direct CO emissions and ease the imbalance between one of the major sectors where emissions are still rising the supply and demand of oil [8]. [1–4]. Within the transport sector, road transport is by Because electric vehicles (EVs) are often con- far the biggest emitter, accounting for more than half of sidered a promising technology and an attractive solu- all transport-related GHG emissions. Rapidly growing tion for low-carbon transport [9, 10], several mobility needs and private vehicle ownership counteract governments have set goals and timelines for the theglobaleffortstoreduceglobalGHG emissionsfrom phase-out of diesel and then gasoline engines by 2050. transport [5]. Due to society’s persistent reliance on fossil The European Union aims to be a major force in the fuels, the reduction of global GHG emissions from EV market, and most European countries have assem- transport to limit the magnitude or rate of long-term bled a series of measures that would help them revita- climate changewillbemorechallenging than in other lize the automotive industry and provide more high- sectors [6, 7]. Low-carbon vehicles, powered by technology jobs. The United States does not have a © 2020 The Author(s). Published by IOP Publishing Ltd Environ. Res. Lett. 15 (2020) 034019 federal policy to boost EV adoption, but several states network. The associated infrastructure, i.e. suitable have set goals to reduce national vehicle emissions to recharging points, is another determining condition zero by 2050. Japan has set a goal of selling only EVs by for a fully electrified transport system [25–27]. 2050. India is one of the few countries that has a con- Although EVs will probably make up a significant por- crete strategy for transport electrification and also has tion of our future transport needs due to technological committed to end the sale of fossil-fuel powered vehi- development and decreasing battery costs, it is neces- cles by 2030. China is working on a plan to ban the sary to investigate whether EVs are as green as they are production and sale of vehicles powered solely by fos- claimed to be and what overall results transport elec- sil fuels and achieve a zero-emissions fleet by 2050. In trification policies may have. developing countries there are a range of policies, with To investigate how transport electrification would some countries embracing the future of electric-pow- impact emission trajectories and climate change, as well ered mobility, while others are skeptical about whe- as what policies and strategies are needed for emission ther EVs will penetrate the market and have resisted reduction and climate change mitigation, this study the trend toward transport electrification. Although employed a global transport model to project the global many countries have proposed bans to prohibit vehi- transport demand of passengers and freight in terms of cles powered by diesel or gasoline, only a few nations the choice of transport mode and its technological details or individual cities have actually legislated against to predict world transport energy use and emissions. The internal combustion engine (ICE) vehicles. Thus, transport model was coupled with a global economic most vehicle bans will not be effective due to the lack model and a simplified climate model to reveal the inter- of legal enforcement [11]. active mechanisms between transport electrification, Existing studies have identified the potential mar- economics, energy, and climate change. Such model ket for EVs and the key factors affecting EV utilization coupling will enable electrified transport to be repre- and benefits, such as vehicle usage behavior, cost, bat- sented in an IAM by providing technological or beha- tery weight, charging patterns, battery range limita- vioral factors [28]. To explore the combined effects of tions, and the lack of public awareness about the transport electrification and climate change mitigation availability and practicality of these vehicles, the asso- efforts, we developed a set of six scenarios according to ciated infrastructure, and safety regulations [9, 12, 13]. socioeconomic pathways, transport electrification strate- Different types of EV (battery EVs, hybrid EVs, and gies, and energy policies, such as carbon pricing and a plug-in hybrid EVs) have been compared to determine high reliance on renewable energy. the vehicle technology that is likely to dominate in the coming decades [10]. Because integrated assessment 2. Methods models (IAMs) have been extensively used to explore decarbonizing pathways in the transport sector [2, 3, 2.1. Transport model 14–20], representations of technological advance- A global transport model was employed to provide ment, consumer preferences, and increased market spatially flexible and temporally dynamic simulations of shares of EVs have been input to global IAMs [5, transport demand, energy use, and emissions with 21–23]. Current research clearly indicates the over- consideration given to various technological factors such whelming importance of the role of transport elec- as device cost, speed, travel time, load factor, and trification in a low-carbon transition. However, preferences. The transport model was developed as a despite EVs reducing transport-related emissions and one-year interval, recursive-type transport choice model, these benefits not being substantially affected by chan- which is described in detail in Zhang et al (2018) [29].A ges in travel distances, battery ranges, or charging fre- summary of the model structure and its equations is quencies [24], it is still very difficult to detect the cross- provided in the supplementary information, available sectoral effects of transport electrification (e.g. the online at stacks.iop.org/ERL/15/034019/mmedia.The impact of the deployment of EVs on the CO emitted model considered different distances, modes, sizes, and by the power sector and the impact of EV penetration technologies for the global projection of passenger and on mitigation costs). It remains uncertain if EVs will freight transport demand in 17 regions around the world deliver the transition toward a green future. (see supplementary figure S1 and table S1).Global Unlike ICEs, EVs do not emit carbon dioxide, but the power in their batteries must be sourced from passenger and freight transport demand was distin- guished between short- and long-distance travel, and somewhere. A transport electrification policy could produce an additional demand for electricity, which different modes, vehicle sizes, and technologies (see supplementary table S2).Energyuse andCO emissions could result in an increase in emissions if the electricity is generated from fossil fuels. It would be problematic from transport can be estimated according to technol- ogy-wise transport demand. to overlook the interaction between the transport sec- tor and other sectors (e.g. the power sector) when the The passenger and freight transport demand was calculated by GDP, industrial value added, popula- deployment of EVs is implemented. The electrifica- tion of the transport sector requires the integration of tion, and generalized transport cost. Then, discrete vehicles into a reliable and efficient clean energy choice models were used to compute the shares of 2 Environ. Res. Lett. 15 (2020) 034019 Figure 1. Model structure. different distances, modes, sizes, and technologies to the transport model to project the transport based on the generalized transport cost, which demand, with consideration given to the modal includes the fuel cost, device cost, infrastructure cost, structure and technology shares. Then, the transport time cost, and carbon price. Fuel cost was calculated demand, energy consumption from transport, and by fuel price and vehicle energy efficiency. Device cost transport device cost from the transport model were was the annualized purchase cost for the vehicle fed back to the economic model to re-estimate the device. The cost of travel time was estimated by the parameters. This loop continued until the energy wage rate and vehicle speed. Infrastructure cost was consumption from transport calculated in the eco- the expense related to the infrastructure upgrades nomic model and the transport model were equal. required at filling stations and EV charging stations. Next, global GHGs and other air pollutant emissions Technological improvements in EVs were incorpo- were passed to the climate model to generate climate rated into the process of technology selection. outcomes, such as radiative forcing and global mean Technology selection parameters for EVs (cars, buses, temperature changes. The mitigation costs, such as two-wheelers, and small trucks) in future years aligned carbon price and economic losses were estimated by with different scenarios would increase gradually, the CGE model according to the emission constraints accompanied by the implementation of transport elec- given by a Dynamic Integrated Climate—Economy— trification policies. The transport and energy data type intertemporal model. from 17 regions that were used for parameter estima- tion and calibration were collected from the Asia-Paci- 2.3. Scenario settings fic Integrated Model database. The detailed data Scenario simulations were developed not only to prove sources used in the transport model are listed in sup- the positive effects of the deployment of EVs on plementary table S3. transport decarbonization and emission reduction but also to detect how transport electrification polices 2.2. Model coupling with a global economic model interact with the power sector. A set of scenarios was The transport model was coupled with a global created to investigate the long-term (to year 2100) economic model and climate model to capture the impacts under various EV technology assumptions interactions and tradeoffs between the transport and energy policy schemes. These scenarios were sector, energy, emissions, macroeconomy, and climate defined according to two dimensions covering the change (figure 1). The frameworks of the computable model assumptions of transport electrification and general equilibrium (CGE) model and the Model for energy policies, respectively. Transport electrification the Assessment of Greenhouse-gas Induced Climate is designed based on the technological preferences for Change were employed for global economic and EVs, including cars, buses, two-wheelers, and small climate modeling. The CGE model was developed for trucks, which reflect the key behavioral factors influ- 17 regions, which was consistent with the transport encing consumers’ willingness to purchase or select model. The CGE model is classified as a multi- EVs. It was assumed that 100% EV market share will regional, multi-sectoral model that covers all eco- be achieved around the world by 2050 due to the EV nomic goods, while considering production factor policy incentives in the HiEV scenarios, while no interactions [30]. An iterative procedure was used to stringent EV policy would be considered in the LoEV obtain the convergence of the coupled model. The scenarios. In the HiEV scenarios, the parameters of the economic model passed the macroeconomic variables technological preferences for ICE vehicles were 3 Environ. Res. Lett. 15 (2020) 034019 Table 1. Scenario settings. Scenario Description LoEV_BaU No EV policy, with no climate efforts LoEV_2D No EV policy, with carbon pricing for the 2 °C target LoEV_Renew No EV policy, with a high preference for renewable energy HiEV_BaU 100% EV market share by 2050, with no climate efforts HiEV_2D 100% EV market share by 2050, with carbon pricing for the 2 °C target HiEV_Renew 100% EV market share by 2050, with a high preference for renewable energy exogenously set to zero by 2050, while higher pre- major contributors to CO emissions, whereas with the ference parameters were given in relation to consu- policy goal of 100% EVs, emissions from road trans- mer’s purchasing decisions regarding EVs to achieve port, including cars, buses, two-wheelers, and small the target of 100% market share. trucks, decreased to zero. In all the transport electrifica- Scenarios for energy policies included carbon pri- tion scenarios, transport modes such as large trucks, cing and a preference for renewable energy. The car- aviation, and navigation, which are currently difficult to bon pricing scenarios considered corresponded to a electrify without breakthrough efforts and technologi- 2 °C climate stabilization target versus no climate cal changes, are expected to emit most emissions in the action. The ‘BaU’ scenario assumed no climate mitiga- future. Moreover, the deployment of EVs (HiEV_BaU) tion efforts, whereas the ‘2D’ scenario imposed a price was more effective at reducing emissions than carbon on carbon, which was consistent with the 2 °C target, pricing without the introduction of EVs (LoEV_2D), with the global mean temperature increase peaking at because road transport cannot achieve zero emissions 1.82 °C in 2090 and settling at 1.8 °C in 2100. The by the implementation of carbon pricing alone. A high radiative forcing level associated with the 2 °C target preference for renewable energies did not have direct −2 was around 2.8 W m in 2100. The radiative forcing positive effects on emission reduction in the transport for the BaU and 2D targets is provided in supplemen- sector. Time series results of energy use and mode-wise tary figure S2. The renewable energy preference sce- emission trajectories are provided in supplementary narios examined the sensitivity of high preferences on figures S3 and S4, respectively. renewable energies. In the CGE model, a factor for Despite the powerful and effective impact of trans- representing renewable energy preference determined port electrification on reducing direct CO emissions the share parameter as a logit function, which acceler- from the transport sector, it is unwise to reach an ated the usage of renewable energies, such as wind and overly optimistic conclusion by ignoring the indirect solar, when a high value was used. CO emissions from the electricity generation that Such scenario settings, considering the different energizes EVs. As displayed in figure 3, the deploy- model assumptions of the transport and power sec- ment of EVs increases emissions from electricity pro- tors, were structured to analyze cross-sectoral rela- duction. A comparison of HiEV_BaU with LoEV_BaU tions and tradeoffs, while also assessing mitigation shows an increase in indirect emissions, although pathways associated with the deployment of EVs direct emissions decrease with the stringent penetra- (table 1). The default values of the underlying socio- tion of EVs during 2005–2100. Thus, without dec- economic conditions, other than road transport-rela- arbonization of the future power supply by means of ted parameters (e.g. GDP and population), were based energy policies, instead of a low-carbon transition, on Shared Socioeconomic Pathway 2 (SSP2) [31]. electrified transport would lead to an increase in total emissions. A high preference for renewable energy would reduce the indirect emissions to some extent, 3. Results whereas a significant emission reduction could be achieved by carbon pricing. 3.1. Energy use and emissions from transport The energy use in the transport sector indicated that the 3.2. Emissions from the power sector transport sector would consume more electricity if the Figure 4(a) presents a more detailed analysis of CO targets for the implementation of electric road transport emissions from the energy-supply sector. Without the were achieved through scenarios HiEV_BaU, HiEV_2D, and HiEV_Renew, regardless of whether ambitious climate change mitigation efforts in the power sector, the deployment of EVs resulted in energy policies were established (figure 2(a)).However, the global consumption of oil and biomass was lower increased emissions from energy production. Such increases in energy-supply-related emissions can be with the deployment of EVs, implying that transport electrification could reduce oil dependency and the interpreted as a globally growing demand for the electricity required as a result of deploying more EVs. moderate demand for biofuels. Figure 2(b) shows the CO emissions by transport mode. Without ambitious The emission trajectories of LoEV_2D and HiEV_2D transport electrification goals, cars and trucks were showed that carbon pricing could significantly reduce 4 Environ. Res. Lett. 15 (2020) 034019 Figure 2. Effects of transport electrification on energy use and CO emissions. Energy use from transport (a) and emissions from transport (b). Figure 3. Direct CO emissions from transport and indirect CO emissions from electricity generation that energize electric vehicles 2 2 (EVs). Figure 4. CO emissions from the energy sector (a), and global mean temperature increase above pre-industrial levels (b). 5 Environ. Res. Lett. 15 (2020) 034019 Figure 5. Global energy supply for electricity generation. Figure 6. Impacts of transport electrification on the consumption of biomass. the emissions in the energy-supply sector, because of rapid transition in the supply base of transport fuels. the switch to renewable and less carbon intensive fuels However, as shown in figure 2(a), it has already been (figure 5; see power generation composition and confirmed that transport electrification exerts a nega- primary energy in supplementary figures S5 and S6). tive impact on biomass consumption in the transport As shown in figure 4(b), deploying EVs alone could sector. More interestingly, similar results were appar- not effectively mitigate temperature increases, imply- ent when all sectors were considered, as shown in ing that an EV policy will not reduce CO emissions 2 figure 6. The deployment of EVs produced a lower from all sectors if the transport is not powered by consumption of biomass. Because biomass produc- decarbonized electricity generation (see emissions by tion may compete with other land uses or land covers, sector in supplementary figure S7). there is a major debate concerning whether the biomass feedstock production required by ambitious biofuel targets will threaten food security, exacerbate 3.3. Biofuel deforestation, destroy ecosystems, and aggravate rural In the near future, biofuels such as ethanol and biogas poverty [33–35]. Our simulations of transport electri- are expected to be at the leading edge of transport fication proved that an EV policy could be a promising decarbonization [32]. The widespread adoption of solution for easing the increasing demand on biomass, ambitious biofuel policies would apparently deliver a 6 Environ. Res. Lett. 15 (2020) 034019 Figure 7. Effects of transport electrification on the total annualized costs of road transport. Figure 8. Mitigation cost metrics for the 2 °C target. which would help mitigate the risk of increasing food Another measure of the economic effects of trans- insecurity due to ambitious biofuel goals. port electrification is to detect how the cost of climate change mitigation would be modified with the strin- gent penetration of EVs, which can be indicated by 3.4. Economic results carbon price, GDP loss rate, and welfare loss rate The economic costs and benefits of transport electrifi- required to achieve an emission reduction consistent cation over the long term were evaluated using a global with the stabilization objective of the 2 °C scenario. transport model coupled with an economic model, Figure 8 shows that the carbon price for achieving the with the coupling model describing the interactions target of a 2 °C global temperature rise decreased from between the transport sector and macroeconomy. 1072 to 511 USD in 2100 due to the undertaking of an Figure 7 shows the total annualized cost of road ambitious transport electrification policy. The GDP transport during 2005–2100. Cars and small trucks and welfare loss rate associated with pricing carbon were the dominant modes, accounting for a major can be thereby mitigated significantly because the goal proportion of the cost, while device costs generated of emission reduction can be achieved more easily by the highest capital cost compared with energy con- electrification of the road transport sector through sumption and infrastructure. Stringent transport elec- EVs rather than by putting a heavy price on trification goals require higher capital costs for the carbon emissions. Carbon-neutral road transport can vehicle, mainly due to the more expensive components instantly contribute to the reduction of transport- of EVs. Although the device cost of EVs is assumed to related emissions by accelerating the market diffusion continue to decline over the coming decades, it is still of EVs, which helps to relieve the negative impacts likely to be higher than that of ICE vehicles. of climate change mitigation efforts on the 7 Environ. Res. Lett. 15 (2020) 034019 Figure 9. Emission trajectories for different EV market shares. Between LoEV (no EV policy) and HiEV (100% EV market share), three additional EV market penetrations were assumed: EV30, EV50, and EV70 (i.e. 30%, 50%, and 70% market shares, respectively). macroeconomy. Therefore, economic development whereas opposite profiles can be found especially for does not necessarily have to run counter to climate the total emissions during 2030–2080 because the change policy goals when low-carbon transport tech- reduction in indirect emissions offsets the increases in nologies are taken into consideration. direct emissions. The robustness of model coupling and stringent EV penetration was verified by a 3.5. Sensitivity analysis sensitivity analysis of the multiple market shares. Driven by transport electrification policies, the market In addition, there were also uncertainties regard- share of EVs has been projected to increase signifi- ing the different socioeconomic assumptions of cantly in the coming decades. However, there is still population and economic growth. Here, multiple uncertainty related to the future prospects of complete socioeconomic pathways were assumed that were EV penetration by 2050, because only a few govern- aligned with SSP1-3 to explore how socioeconomic ments have legislated to ban ICE vehicle sales. Thus, to factors influenced the emission profiles when con- understand more fully the relationships between sidering stringent transport electrification. It was policy settings and model outputs, it is necessary to test possible to determine whether there were futures whether the model and its results are robust in the where transport electrification was more or less bene- presence of uncertainty. One way to perform an ficial, even in the absence of complete power sector uncertainty and sensitivity analysis is to simulate a decarbonization. Figure 10 shows the emission pro- range of transport electrification scenarios rather than files for the three SSP scenarios. Transport electrifica- by focusing on a 100% market share of EVs. Figure 9 tion reduced direct emissions from the transport displays the CO emission trajectories, with considera- sector, but indirect emissions increased significantly tion given to different EV market shares between the in all three SSP scenarios. However, when LoEV and HiEV scenarios. The trajectories of the considering the tradeoff between direct and indirect direct emissions when assuming 30%, 50%, and 70% emissions, the total emissions displayed differences market shares of EV penetration were higher than among the three SSPs. Interestingly, the stringent those for HiEV and lower than those for LoEV, penetration of EVs reduced the total CO emissions regardless of whether renewables penetrate further the in SSP1, whereas in SSP2 and SSP3 there were increa- energy mix or not. The indirect emissions exhibited ses in total emissions when the 100% market share of contrasting features, but the greater the market share, EVs was achieved. Even without a decarbonized the higher the indirect emissions. However, total power sector through carbon pricing or renewable emissions displayed the different dynamics between energy policies, transport electrification aligned BaU and Renew. Without high preference for renew- with SSP1 was able to meet the CO emission reduc- able energies, total emissions showed increasing trends tion target. in alignment with high market diffusion of EVs, 8 Environ. Res. Lett. 15 (2020) 034019 Figure 10. Emission profiles in three Shared Socioeconomic Pathways (SSP1-3) scenarios. Figure 11. An electric vehicle (EV) policy alone shifts emissions from the transport sector to the power sector. 4. Discussion and conclusion Although homogenous targets of 100% market share were established for the stringent EV scenarios Many governments have encouraged the adoption of in 17 regions, governments have actually set different EVs as an important step toward a clean energy future timelines for the phase-out of ICE vehicles (see supple- because of their contribution toward reducing direct mentary table S4). According to these different emissions from transport. However, our research national transport electrification goals, heterogeneous confirmed that an EV policy without decarbonizing market shares for EV scenarios were designed to power generation fails to contribute to emission reflect policy variation and estimate the emission tra- reduction, although direct emissions from transport jectories considering regional heterogeneity in policy can be reduced significantly because an EV policy timelines and goals. Figure 12 shows the emission tra- would shift emissions from the transport sector to the jectories with the setting of regionally specific ICE power sector (figure 11). Despite the rapid technologi- bans. It was assumed that more ambitious targets for cal progress made with EV technologies, an analysis of EV penetration would be established in the EU, combined transport electrification and energy policies Canada, and India, in view of their national strategies revealed an uncomfortable truth—transport electrifi- for transport electrification, while default values for cation alone does not successfully reduce emissions deploying EVs were set for other countries and regions and mitigate climate change. Instead, to meet stringent such as the US, China, and Japan. Regardless of whe- climate targets, the linkages between the transport ther carbon pricing and renewable energy policies sector and energy sector deserve attention. Renewable were deployed, additional emission reductions could energy as a means to decarbonize power generation be realized globally due to the different regional EV needs to play a key role when electrifying the transport diffusion policies. Because transport emissions in the sector. EU, Canada, and India account for approximately a 9 Environ. Res. Lett. 15 (2020) 034019 Figure 12. Emission trajectories after setting regionally specific targets on electric vehicle (EV) sales. Homogeneous targets for EV sales indicated that a 100% market share will be achieved by 2050 for all regions worldwide. Regionally specific targets were set for 100% market shares by 2030 (the EU and India), 2040 (Canada), and 2050 (other regions such as the US, China, Japan, etc). quarter of global transport emissions, earlier timelines economic growth due to imposition of a carbon tax for for ICE bans in these three regions would accelerate achieving climate change mitigation targets. The the global emission reduction. The regional emission impact on the dynamics of the macroeconomy of trajectories considering these policy variations are transport electrification needs to be considered when provided in supplementary figure S8. evaluating the feasibility and cost-effectiveness of EV Our findings should not be interpreted to down- policies. Climate action does not have to decrease eco- play the contribution of transport electrification to cli- nomic growth and it is not certain that economic mate change mitigation or to deemphasize the role of sacrifice will be required. It is possible to propose a EVs as a potential solution toward a low-carbon trans- win-win strategy of low-carbon transition and eco- ition. Rather, we highlight the interaction required nomic development. On the other hand, from the between transport electrification and the power sector viewpoint of consumers, an electrified transport sector to formulate more harmonized and inclusive policies. requires additional vehicle purchase costs for EVs Combining transport electrification with energy poli- compared to a conventional ICE driven vehicle, cies, such as carbon pricing, could facilitate emission mainly because of the cost of the battery. Although reductions from transport and a simultaneous trans- battery costs are projected to decrease due to improve- ition to a low-carbon future. Interestingly, transport ments in the materials used as well as the potential for electrification can also be considered a potential policy large-scale manufacturing [22], economic policy tool to alleviate the negative impacts of biofuel devel- incentives such as subsidies for EVs need to be con- opment on food security due to ambitious climate sidered to reduce the additional costs of EVs directly change mitigation targets. Moreover, it was found that and stimulate consumers to purchase them. In this the emission reduction effect of stringent EV goals was study, scenario settings for stringent EV penetration not dependent on the decarbonized power sector or were represented only by ICE vehicle bans, and did not accompanying energy policies in SSP1, which depicts involve other specific EV policies, such as purchasing features of a sustainable future, with low fossil-fuel subsidies, exemptions from tolls, and registration fees. dependence and an increasing share of renewables. Further studies are needed to determine how financial SSP1 is characterized as ‘Taking the Green Road’, with incentives for EV use would modify the market share low population projections but high productivity, of EVs in the coming decades. leading to lower CO emissions and fewer challenges Although this study was aimed at determining the to climate change mitigation. Because the world is role of transport electrification using a global trans- oriented toward lower resource use and energy inten- port model coupled with economic and climate mod- sity in SSP1, a widespread transition to a zero-carbon els, there are limitations to the study that should be road transport sector might not have side effects. noted. The temporal dynamics associated with EV Because the effectiveness of transport electrification charging were not taken into consideration and, policy is determined by socioeconomic pathways, therefore, the current model framework did not con- transport planners, energy experts, policymakers, duct an analysis of the hourly balance between EV economists, and stakeholders need to work together to charging loads and electricity generation. In future develop a joint strategy for transport electrification to studies, a detailed hourly profile of EV charging reduce CO emissions quickly and effectively. should be explicitly represented. In addition, the Mitigation cost measures represent the econom- emissions produced from the EV manufacturing pro- ical attractiveness of transport electrification as a miti- cess were not included in the global transport model, gation opportunity, because it reduces the loss rates of and will need to be incorporated when estimating the 10 Environ. Res. 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The role of transport electrification in global climate change mitigation scenarios

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Copyright © 2020 The Author(s). Published by IOP Publishing Ltd
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10.1088/1748-9326/ab6658
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Abstract

Any further distribution of this work must maintain Electrification is widely considered an attractive solution for reducing the oil dependency and attribution to the author(s) and the title of environmental impact of road transportation. Many countries have been establishing increasingly the work, journal citation stringent and ambitious targets in support of transport electrification. We conducted scenario and DOI. simulations to depict the role of transport electrification in climate change mitigation and how the transport sector would interact with the energy-supply sector. The results showed that transport electrification without the replacement of fossil-fuel power plants leads to the unfortunate result of increasing emissions instead of achieving a low-carbon transition. While transport electrification alone would not contribute to climate change mitigation, it is interesting to note that switching to electrified road transport under the sustainable shared socioeconomic pathways permitted an optimistic outlook for a low-carbon transition, even in the absence of a decarbonized power sector. Another interesting finding was that the stringent penetration of electric vehicles can reduce the mitigation cost generated by the 2 °C climate stabilization target, implying a positive impact for transport policies on the economic system. With technological innovations such as electrified road transport, climate change mitigation does not have to occur at the expense of economic growth. Because a transport electrification policy closely interacts with energy and economic systems, transport planners, economists, and energy policymakers need to work together to propose policy schemes that consider a cross-sectoral balance for a green sustainable future. 1. Introduction electricity, offer an alternative to conventional fossil-fuel technologies, and switching to electricity for road trans- The transport sector accounts for approximately a port has been proposed as a significant way to reduce quarter of global greenhouse gas (GHG) emissions and is direct CO emissions and ease the imbalance between one of the major sectors where emissions are still rising the supply and demand of oil [8]. [1–4]. Within the transport sector, road transport is by Because electric vehicles (EVs) are often con- far the biggest emitter, accounting for more than half of sidered a promising technology and an attractive solu- all transport-related GHG emissions. Rapidly growing tion for low-carbon transport [9, 10], several mobility needs and private vehicle ownership counteract governments have set goals and timelines for the theglobaleffortstoreduceglobalGHG emissionsfrom phase-out of diesel and then gasoline engines by 2050. transport [5]. Due to society’s persistent reliance on fossil The European Union aims to be a major force in the fuels, the reduction of global GHG emissions from EV market, and most European countries have assem- transport to limit the magnitude or rate of long-term bled a series of measures that would help them revita- climate changewillbemorechallenging than in other lize the automotive industry and provide more high- sectors [6, 7]. Low-carbon vehicles, powered by technology jobs. The United States does not have a © 2020 The Author(s). Published by IOP Publishing Ltd Environ. Res. Lett. 15 (2020) 034019 federal policy to boost EV adoption, but several states network. The associated infrastructure, i.e. suitable have set goals to reduce national vehicle emissions to recharging points, is another determining condition zero by 2050. Japan has set a goal of selling only EVs by for a fully electrified transport system [25–27]. 2050. India is one of the few countries that has a con- Although EVs will probably make up a significant por- crete strategy for transport electrification and also has tion of our future transport needs due to technological committed to end the sale of fossil-fuel powered vehi- development and decreasing battery costs, it is neces- cles by 2030. China is working on a plan to ban the sary to investigate whether EVs are as green as they are production and sale of vehicles powered solely by fos- claimed to be and what overall results transport elec- sil fuels and achieve a zero-emissions fleet by 2050. In trification policies may have. developing countries there are a range of policies, with To investigate how transport electrification would some countries embracing the future of electric-pow- impact emission trajectories and climate change, as well ered mobility, while others are skeptical about whe- as what policies and strategies are needed for emission ther EVs will penetrate the market and have resisted reduction and climate change mitigation, this study the trend toward transport electrification. Although employed a global transport model to project the global many countries have proposed bans to prohibit vehi- transport demand of passengers and freight in terms of cles powered by diesel or gasoline, only a few nations the choice of transport mode and its technological details or individual cities have actually legislated against to predict world transport energy use and emissions. The internal combustion engine (ICE) vehicles. Thus, transport model was coupled with a global economic most vehicle bans will not be effective due to the lack model and a simplified climate model to reveal the inter- of legal enforcement [11]. active mechanisms between transport electrification, Existing studies have identified the potential mar- economics, energy, and climate change. Such model ket for EVs and the key factors affecting EV utilization coupling will enable electrified transport to be repre- and benefits, such as vehicle usage behavior, cost, bat- sented in an IAM by providing technological or beha- tery weight, charging patterns, battery range limita- vioral factors [28]. To explore the combined effects of tions, and the lack of public awareness about the transport electrification and climate change mitigation availability and practicality of these vehicles, the asso- efforts, we developed a set of six scenarios according to ciated infrastructure, and safety regulations [9, 12, 13]. socioeconomic pathways, transport electrification strate- Different types of EV (battery EVs, hybrid EVs, and gies, and energy policies, such as carbon pricing and a plug-in hybrid EVs) have been compared to determine high reliance on renewable energy. the vehicle technology that is likely to dominate in the coming decades [10]. Because integrated assessment 2. Methods models (IAMs) have been extensively used to explore decarbonizing pathways in the transport sector [2, 3, 2.1. Transport model 14–20], representations of technological advance- A global transport model was employed to provide ment, consumer preferences, and increased market spatially flexible and temporally dynamic simulations of shares of EVs have been input to global IAMs [5, transport demand, energy use, and emissions with 21–23]. Current research clearly indicates the over- consideration given to various technological factors such whelming importance of the role of transport elec- as device cost, speed, travel time, load factor, and trification in a low-carbon transition. However, preferences. The transport model was developed as a despite EVs reducing transport-related emissions and one-year interval, recursive-type transport choice model, these benefits not being substantially affected by chan- which is described in detail in Zhang et al (2018) [29].A ges in travel distances, battery ranges, or charging fre- summary of the model structure and its equations is quencies [24], it is still very difficult to detect the cross- provided in the supplementary information, available sectoral effects of transport electrification (e.g. the online at stacks.iop.org/ERL/15/034019/mmedia.The impact of the deployment of EVs on the CO emitted model considered different distances, modes, sizes, and by the power sector and the impact of EV penetration technologies for the global projection of passenger and on mitigation costs). It remains uncertain if EVs will freight transport demand in 17 regions around the world deliver the transition toward a green future. (see supplementary figure S1 and table S1).Global Unlike ICEs, EVs do not emit carbon dioxide, but the power in their batteries must be sourced from passenger and freight transport demand was distin- guished between short- and long-distance travel, and somewhere. A transport electrification policy could produce an additional demand for electricity, which different modes, vehicle sizes, and technologies (see supplementary table S2).Energyuse andCO emissions could result in an increase in emissions if the electricity is generated from fossil fuels. It would be problematic from transport can be estimated according to technol- ogy-wise transport demand. to overlook the interaction between the transport sec- tor and other sectors (e.g. the power sector) when the The passenger and freight transport demand was calculated by GDP, industrial value added, popula- deployment of EVs is implemented. The electrifica- tion of the transport sector requires the integration of tion, and generalized transport cost. Then, discrete vehicles into a reliable and efficient clean energy choice models were used to compute the shares of 2 Environ. Res. Lett. 15 (2020) 034019 Figure 1. Model structure. different distances, modes, sizes, and technologies to the transport model to project the transport based on the generalized transport cost, which demand, with consideration given to the modal includes the fuel cost, device cost, infrastructure cost, structure and technology shares. Then, the transport time cost, and carbon price. Fuel cost was calculated demand, energy consumption from transport, and by fuel price and vehicle energy efficiency. Device cost transport device cost from the transport model were was the annualized purchase cost for the vehicle fed back to the economic model to re-estimate the device. The cost of travel time was estimated by the parameters. This loop continued until the energy wage rate and vehicle speed. Infrastructure cost was consumption from transport calculated in the eco- the expense related to the infrastructure upgrades nomic model and the transport model were equal. required at filling stations and EV charging stations. Next, global GHGs and other air pollutant emissions Technological improvements in EVs were incorpo- were passed to the climate model to generate climate rated into the process of technology selection. outcomes, such as radiative forcing and global mean Technology selection parameters for EVs (cars, buses, temperature changes. The mitigation costs, such as two-wheelers, and small trucks) in future years aligned carbon price and economic losses were estimated by with different scenarios would increase gradually, the CGE model according to the emission constraints accompanied by the implementation of transport elec- given by a Dynamic Integrated Climate—Economy— trification policies. The transport and energy data type intertemporal model. from 17 regions that were used for parameter estima- tion and calibration were collected from the Asia-Paci- 2.3. Scenario settings fic Integrated Model database. The detailed data Scenario simulations were developed not only to prove sources used in the transport model are listed in sup- the positive effects of the deployment of EVs on plementary table S3. transport decarbonization and emission reduction but also to detect how transport electrification polices 2.2. Model coupling with a global economic model interact with the power sector. A set of scenarios was The transport model was coupled with a global created to investigate the long-term (to year 2100) economic model and climate model to capture the impacts under various EV technology assumptions interactions and tradeoffs between the transport and energy policy schemes. These scenarios were sector, energy, emissions, macroeconomy, and climate defined according to two dimensions covering the change (figure 1). The frameworks of the computable model assumptions of transport electrification and general equilibrium (CGE) model and the Model for energy policies, respectively. Transport electrification the Assessment of Greenhouse-gas Induced Climate is designed based on the technological preferences for Change were employed for global economic and EVs, including cars, buses, two-wheelers, and small climate modeling. The CGE model was developed for trucks, which reflect the key behavioral factors influ- 17 regions, which was consistent with the transport encing consumers’ willingness to purchase or select model. The CGE model is classified as a multi- EVs. It was assumed that 100% EV market share will regional, multi-sectoral model that covers all eco- be achieved around the world by 2050 due to the EV nomic goods, while considering production factor policy incentives in the HiEV scenarios, while no interactions [30]. An iterative procedure was used to stringent EV policy would be considered in the LoEV obtain the convergence of the coupled model. The scenarios. In the HiEV scenarios, the parameters of the economic model passed the macroeconomic variables technological preferences for ICE vehicles were 3 Environ. Res. Lett. 15 (2020) 034019 Table 1. Scenario settings. Scenario Description LoEV_BaU No EV policy, with no climate efforts LoEV_2D No EV policy, with carbon pricing for the 2 °C target LoEV_Renew No EV policy, with a high preference for renewable energy HiEV_BaU 100% EV market share by 2050, with no climate efforts HiEV_2D 100% EV market share by 2050, with carbon pricing for the 2 °C target HiEV_Renew 100% EV market share by 2050, with a high preference for renewable energy exogenously set to zero by 2050, while higher pre- major contributors to CO emissions, whereas with the ference parameters were given in relation to consu- policy goal of 100% EVs, emissions from road trans- mer’s purchasing decisions regarding EVs to achieve port, including cars, buses, two-wheelers, and small the target of 100% market share. trucks, decreased to zero. In all the transport electrifica- Scenarios for energy policies included carbon pri- tion scenarios, transport modes such as large trucks, cing and a preference for renewable energy. The car- aviation, and navigation, which are currently difficult to bon pricing scenarios considered corresponded to a electrify without breakthrough efforts and technologi- 2 °C climate stabilization target versus no climate cal changes, are expected to emit most emissions in the action. The ‘BaU’ scenario assumed no climate mitiga- future. Moreover, the deployment of EVs (HiEV_BaU) tion efforts, whereas the ‘2D’ scenario imposed a price was more effective at reducing emissions than carbon on carbon, which was consistent with the 2 °C target, pricing without the introduction of EVs (LoEV_2D), with the global mean temperature increase peaking at because road transport cannot achieve zero emissions 1.82 °C in 2090 and settling at 1.8 °C in 2100. The by the implementation of carbon pricing alone. A high radiative forcing level associated with the 2 °C target preference for renewable energies did not have direct −2 was around 2.8 W m in 2100. The radiative forcing positive effects on emission reduction in the transport for the BaU and 2D targets is provided in supplemen- sector. Time series results of energy use and mode-wise tary figure S2. The renewable energy preference sce- emission trajectories are provided in supplementary narios examined the sensitivity of high preferences on figures S3 and S4, respectively. renewable energies. In the CGE model, a factor for Despite the powerful and effective impact of trans- representing renewable energy preference determined port electrification on reducing direct CO emissions the share parameter as a logit function, which acceler- from the transport sector, it is unwise to reach an ated the usage of renewable energies, such as wind and overly optimistic conclusion by ignoring the indirect solar, when a high value was used. CO emissions from the electricity generation that Such scenario settings, considering the different energizes EVs. As displayed in figure 3, the deploy- model assumptions of the transport and power sec- ment of EVs increases emissions from electricity pro- tors, were structured to analyze cross-sectoral rela- duction. A comparison of HiEV_BaU with LoEV_BaU tions and tradeoffs, while also assessing mitigation shows an increase in indirect emissions, although pathways associated with the deployment of EVs direct emissions decrease with the stringent penetra- (table 1). The default values of the underlying socio- tion of EVs during 2005–2100. Thus, without dec- economic conditions, other than road transport-rela- arbonization of the future power supply by means of ted parameters (e.g. GDP and population), were based energy policies, instead of a low-carbon transition, on Shared Socioeconomic Pathway 2 (SSP2) [31]. electrified transport would lead to an increase in total emissions. A high preference for renewable energy would reduce the indirect emissions to some extent, 3. Results whereas a significant emission reduction could be achieved by carbon pricing. 3.1. Energy use and emissions from transport The energy use in the transport sector indicated that the 3.2. Emissions from the power sector transport sector would consume more electricity if the Figure 4(a) presents a more detailed analysis of CO targets for the implementation of electric road transport emissions from the energy-supply sector. Without the were achieved through scenarios HiEV_BaU, HiEV_2D, and HiEV_Renew, regardless of whether ambitious climate change mitigation efforts in the power sector, the deployment of EVs resulted in energy policies were established (figure 2(a)).However, the global consumption of oil and biomass was lower increased emissions from energy production. Such increases in energy-supply-related emissions can be with the deployment of EVs, implying that transport electrification could reduce oil dependency and the interpreted as a globally growing demand for the electricity required as a result of deploying more EVs. moderate demand for biofuels. Figure 2(b) shows the CO emissions by transport mode. Without ambitious The emission trajectories of LoEV_2D and HiEV_2D transport electrification goals, cars and trucks were showed that carbon pricing could significantly reduce 4 Environ. Res. Lett. 15 (2020) 034019 Figure 2. Effects of transport electrification on energy use and CO emissions. Energy use from transport (a) and emissions from transport (b). Figure 3. Direct CO emissions from transport and indirect CO emissions from electricity generation that energize electric vehicles 2 2 (EVs). Figure 4. CO emissions from the energy sector (a), and global mean temperature increase above pre-industrial levels (b). 5 Environ. Res. Lett. 15 (2020) 034019 Figure 5. Global energy supply for electricity generation. Figure 6. Impacts of transport electrification on the consumption of biomass. the emissions in the energy-supply sector, because of rapid transition in the supply base of transport fuels. the switch to renewable and less carbon intensive fuels However, as shown in figure 2(a), it has already been (figure 5; see power generation composition and confirmed that transport electrification exerts a nega- primary energy in supplementary figures S5 and S6). tive impact on biomass consumption in the transport As shown in figure 4(b), deploying EVs alone could sector. More interestingly, similar results were appar- not effectively mitigate temperature increases, imply- ent when all sectors were considered, as shown in ing that an EV policy will not reduce CO emissions 2 figure 6. The deployment of EVs produced a lower from all sectors if the transport is not powered by consumption of biomass. Because biomass produc- decarbonized electricity generation (see emissions by tion may compete with other land uses or land covers, sector in supplementary figure S7). there is a major debate concerning whether the biomass feedstock production required by ambitious biofuel targets will threaten food security, exacerbate 3.3. Biofuel deforestation, destroy ecosystems, and aggravate rural In the near future, biofuels such as ethanol and biogas poverty [33–35]. Our simulations of transport electri- are expected to be at the leading edge of transport fication proved that an EV policy could be a promising decarbonization [32]. The widespread adoption of solution for easing the increasing demand on biomass, ambitious biofuel policies would apparently deliver a 6 Environ. Res. Lett. 15 (2020) 034019 Figure 7. Effects of transport electrification on the total annualized costs of road transport. Figure 8. Mitigation cost metrics for the 2 °C target. which would help mitigate the risk of increasing food Another measure of the economic effects of trans- insecurity due to ambitious biofuel goals. port electrification is to detect how the cost of climate change mitigation would be modified with the strin- gent penetration of EVs, which can be indicated by 3.4. Economic results carbon price, GDP loss rate, and welfare loss rate The economic costs and benefits of transport electrifi- required to achieve an emission reduction consistent cation over the long term were evaluated using a global with the stabilization objective of the 2 °C scenario. transport model coupled with an economic model, Figure 8 shows that the carbon price for achieving the with the coupling model describing the interactions target of a 2 °C global temperature rise decreased from between the transport sector and macroeconomy. 1072 to 511 USD in 2100 due to the undertaking of an Figure 7 shows the total annualized cost of road ambitious transport electrification policy. The GDP transport during 2005–2100. Cars and small trucks and welfare loss rate associated with pricing carbon were the dominant modes, accounting for a major can be thereby mitigated significantly because the goal proportion of the cost, while device costs generated of emission reduction can be achieved more easily by the highest capital cost compared with energy con- electrification of the road transport sector through sumption and infrastructure. Stringent transport elec- EVs rather than by putting a heavy price on trification goals require higher capital costs for the carbon emissions. Carbon-neutral road transport can vehicle, mainly due to the more expensive components instantly contribute to the reduction of transport- of EVs. Although the device cost of EVs is assumed to related emissions by accelerating the market diffusion continue to decline over the coming decades, it is still of EVs, which helps to relieve the negative impacts likely to be higher than that of ICE vehicles. of climate change mitigation efforts on the 7 Environ. Res. Lett. 15 (2020) 034019 Figure 9. Emission trajectories for different EV market shares. Between LoEV (no EV policy) and HiEV (100% EV market share), three additional EV market penetrations were assumed: EV30, EV50, and EV70 (i.e. 30%, 50%, and 70% market shares, respectively). macroeconomy. Therefore, economic development whereas opposite profiles can be found especially for does not necessarily have to run counter to climate the total emissions during 2030–2080 because the change policy goals when low-carbon transport tech- reduction in indirect emissions offsets the increases in nologies are taken into consideration. direct emissions. The robustness of model coupling and stringent EV penetration was verified by a 3.5. Sensitivity analysis sensitivity analysis of the multiple market shares. Driven by transport electrification policies, the market In addition, there were also uncertainties regard- share of EVs has been projected to increase signifi- ing the different socioeconomic assumptions of cantly in the coming decades. However, there is still population and economic growth. Here, multiple uncertainty related to the future prospects of complete socioeconomic pathways were assumed that were EV penetration by 2050, because only a few govern- aligned with SSP1-3 to explore how socioeconomic ments have legislated to ban ICE vehicle sales. Thus, to factors influenced the emission profiles when con- understand more fully the relationships between sidering stringent transport electrification. It was policy settings and model outputs, it is necessary to test possible to determine whether there were futures whether the model and its results are robust in the where transport electrification was more or less bene- presence of uncertainty. One way to perform an ficial, even in the absence of complete power sector uncertainty and sensitivity analysis is to simulate a decarbonization. Figure 10 shows the emission pro- range of transport electrification scenarios rather than files for the three SSP scenarios. Transport electrifica- by focusing on a 100% market share of EVs. Figure 9 tion reduced direct emissions from the transport displays the CO emission trajectories, with considera- sector, but indirect emissions increased significantly tion given to different EV market shares between the in all three SSP scenarios. However, when LoEV and HiEV scenarios. The trajectories of the considering the tradeoff between direct and indirect direct emissions when assuming 30%, 50%, and 70% emissions, the total emissions displayed differences market shares of EV penetration were higher than among the three SSPs. Interestingly, the stringent those for HiEV and lower than those for LoEV, penetration of EVs reduced the total CO emissions regardless of whether renewables penetrate further the in SSP1, whereas in SSP2 and SSP3 there were increa- energy mix or not. The indirect emissions exhibited ses in total emissions when the 100% market share of contrasting features, but the greater the market share, EVs was achieved. Even without a decarbonized the higher the indirect emissions. However, total power sector through carbon pricing or renewable emissions displayed the different dynamics between energy policies, transport electrification aligned BaU and Renew. Without high preference for renew- with SSP1 was able to meet the CO emission reduc- able energies, total emissions showed increasing trends tion target. in alignment with high market diffusion of EVs, 8 Environ. Res. Lett. 15 (2020) 034019 Figure 10. Emission profiles in three Shared Socioeconomic Pathways (SSP1-3) scenarios. Figure 11. An electric vehicle (EV) policy alone shifts emissions from the transport sector to the power sector. 4. Discussion and conclusion Although homogenous targets of 100% market share were established for the stringent EV scenarios Many governments have encouraged the adoption of in 17 regions, governments have actually set different EVs as an important step toward a clean energy future timelines for the phase-out of ICE vehicles (see supple- because of their contribution toward reducing direct mentary table S4). According to these different emissions from transport. However, our research national transport electrification goals, heterogeneous confirmed that an EV policy without decarbonizing market shares for EV scenarios were designed to power generation fails to contribute to emission reflect policy variation and estimate the emission tra- reduction, although direct emissions from transport jectories considering regional heterogeneity in policy can be reduced significantly because an EV policy timelines and goals. Figure 12 shows the emission tra- would shift emissions from the transport sector to the jectories with the setting of regionally specific ICE power sector (figure 11). Despite the rapid technologi- bans. It was assumed that more ambitious targets for cal progress made with EV technologies, an analysis of EV penetration would be established in the EU, combined transport electrification and energy policies Canada, and India, in view of their national strategies revealed an uncomfortable truth—transport electrifi- for transport electrification, while default values for cation alone does not successfully reduce emissions deploying EVs were set for other countries and regions and mitigate climate change. Instead, to meet stringent such as the US, China, and Japan. Regardless of whe- climate targets, the linkages between the transport ther carbon pricing and renewable energy policies sector and energy sector deserve attention. Renewable were deployed, additional emission reductions could energy as a means to decarbonize power generation be realized globally due to the different regional EV needs to play a key role when electrifying the transport diffusion policies. Because transport emissions in the sector. EU, Canada, and India account for approximately a 9 Environ. Res. Lett. 15 (2020) 034019 Figure 12. Emission trajectories after setting regionally specific targets on electric vehicle (EV) sales. Homogeneous targets for EV sales indicated that a 100% market share will be achieved by 2050 for all regions worldwide. Regionally specific targets were set for 100% market shares by 2030 (the EU and India), 2040 (Canada), and 2050 (other regions such as the US, China, Japan, etc). quarter of global transport emissions, earlier timelines economic growth due to imposition of a carbon tax for for ICE bans in these three regions would accelerate achieving climate change mitigation targets. The the global emission reduction. The regional emission impact on the dynamics of the macroeconomy of trajectories considering these policy variations are transport electrification needs to be considered when provided in supplementary figure S8. evaluating the feasibility and cost-effectiveness of EV Our findings should not be interpreted to down- policies. Climate action does not have to decrease eco- play the contribution of transport electrification to cli- nomic growth and it is not certain that economic mate change mitigation or to deemphasize the role of sacrifice will be required. It is possible to propose a EVs as a potential solution toward a low-carbon trans- win-win strategy of low-carbon transition and eco- ition. Rather, we highlight the interaction required nomic development. On the other hand, from the between transport electrification and the power sector viewpoint of consumers, an electrified transport sector to formulate more harmonized and inclusive policies. requires additional vehicle purchase costs for EVs Combining transport electrification with energy poli- compared to a conventional ICE driven vehicle, cies, such as carbon pricing, could facilitate emission mainly because of the cost of the battery. Although reductions from transport and a simultaneous trans- battery costs are projected to decrease due to improve- ition to a low-carbon future. Interestingly, transport ments in the materials used as well as the potential for electrification can also be considered a potential policy large-scale manufacturing [22], economic policy tool to alleviate the negative impacts of biofuel devel- incentives such as subsidies for EVs need to be con- opment on food security due to ambitious climate sidered to reduce the additional costs of EVs directly change mitigation targets. Moreover, it was found that and stimulate consumers to purchase them. In this the emission reduction effect of stringent EV goals was study, scenario settings for stringent EV penetration not dependent on the decarbonized power sector or were represented only by ICE vehicle bans, and did not accompanying energy policies in SSP1, which depicts involve other specific EV policies, such as purchasing features of a sustainable future, with low fossil-fuel subsidies, exemptions from tolls, and registration fees. dependence and an increasing share of renewables. Further studies are needed to determine how financial SSP1 is characterized as ‘Taking the Green Road’, with incentives for EV use would modify the market share low population projections but high productivity, of EVs in the coming decades. leading to lower CO emissions and fewer challenges Although this study was aimed at determining the to climate change mitigation. Because the world is role of transport electrification using a global trans- oriented toward lower resource use and energy inten- port model coupled with economic and climate mod- sity in SSP1, a widespread transition to a zero-carbon els, there are limitations to the study that should be road transport sector might not have side effects. noted. The temporal dynamics associated with EV Because the effectiveness of transport electrification charging were not taken into consideration and, policy is determined by socioeconomic pathways, therefore, the current model framework did not con- transport planners, energy experts, policymakers, duct an analysis of the hourly balance between EV economists, and stakeholders need to work together to charging loads and electricity generation. In future develop a joint strategy for transport electrification to studies, a detailed hourly profile of EV charging reduce CO emissions quickly and effectively. should be explicitly represented. In addition, the Mitigation cost measures represent the econom- emissions produced from the EV manufacturing pro- ical attractiveness of transport electrification as a miti- cess were not included in the global transport model, gation opportunity, because it reduces the loss rates of and will need to be incorporated when estimating the 10 Environ. Res. 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Environmental Research LettersIOP Publishing

Published: Mar 1, 2020

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