U of Toronto study finds US electrification of LDV fleet not a silver bullet for tackling climate change in vehicle sector

A brand new examine by researchers on the College of Toronto has found that present US insurance policies are inadequate to stay inside a sectoral CO2 emission finances for light-duty autos that’s in line with stopping greater than 2 °C world warming. Present insurance policies will create a mitigation hole of as much as 19 GtCO2 (28% of the projected 2015–2050 light-duty automobile fleet emissions).


2015–2050 US light-duty fleet cumulative CO2 emissions versus CO2 finances below potential future developments. a,b, Baseline circumstances (high dark-blue bar) and modifications in emissions related to rising LDV journey demand, gas consumption requirements and electrification assuming present gas financial system coverage (SAFE requirements) (a) and stringent gas financial system insurance policies (CAFE requirements for typical autos, together with excessive automobile dimension and weight management) (b). Mitigation hole refers back to the distinction between the two °C CO2 emission finances and the emissions with incorporating the earlier methods. SSP1, sustainability—taking the inexperienced street; SSP2, center of the street; SSP5, fossil-fueled growth—taking the freeway. Milovanoff et al.

Closing the mitigation hole solely with EVs would require greater than 350 million on-road EVs (90% of the fleet), half of nationwide electrical energy demand and extreme quantities of vital supplies to be deployed in 2050—a state of affairs thought of unrealistic. The overall proportion of EVs presently on the street within the US is about 0.3%. The paper is revealed within the journal Nature Local weather Change.

Lots of people assume {that a} large-scale shift to EVs will principally clear up our local weather issues within the passenger automobile sector. I believe a greater means to have a look at it’s this: EVs are needed, however on their very own, they aren’t ample.

—Alexandre Milovanoff, lead and corresponding writer

Milovanoff and his supervisors, Professors Daniel Posen and Heather MacLean, ran an in depth lifecycle evaluation of what a large-scale shift to EVs would imply by way of emissions and associated impacts. As a check market, they selected the USA, which is second solely to China by way of passenger automobile gross sales.

The group constructed pc fashions to estimate what number of electrical autos could be wanted to maintain the rise in world common temperatures to lower than 2 C above pre-industrial ranges by the 12 months 2100, a goal usually cited by local weather researchers.

The group developed a two-staged scenario-based evaluation. First, the researchers used the Shared Socioeconomic Pathways (SSPs) to outline US LDV fleet CO2 emission budgets which might be in line with a 2 °C local weather objective below totally different assumptions of potential world societal developments. Second, they used a fleet-based life-cycle evaluation and automobile turnover mannequin of US LDVs to estimate the possible life-cycle CO2 emissions of the fleet below present business-as-usual insurance policies in addition to below excessive electrification situations.

The researchers examined the impression of car traits (for instance, weight and gas consumption) on LDV fleet CO2 emissions after which used a backcasting process to quantify the timing and volumes of EVs required to stay inside appropriate CO2 emission budgets, the ensuing electrical energy use and potential impacts on the electrical energy system, and the fabric flows of the electrical batteries.

Among the many main findings:

  • Present coverage and electrification targets are inadequate to stay inside an acceptable US LDV CO2 emission finances in line with a 2 °C goal. The group estimated 2015–2050 LDV sectoral carbon budgets of 44–50 GtCO2 between the SSPs. If the US LDV fleet stays fixed (in traits, inventory and journey demand) till 2050, 51 GtCO2 could be emitted from 2015 to 2050, making a mitigation hole of 1–7 GtCO2. The excessive finish of this vary exceeds complete US CO2 emissions in 2017 (5.2 Gt), whereas the low finish is half the annual US transportation emissions (1.8 Gt).

    The anticipated rising journey demand of LDVs from rising inhabitants and financial growth broadens the mitigation hole by as much as 20 GtCO2, whereas the minor gas consumption enhancements of the SAFE requirements scale back it by 1 GtCO2. With no extra insurance policies, electrification of US LDVs following the EV30@30 marketing campaign may convey emission reductions of seven–8 GtCO2 with a 2018 electrical energy emission issue, and as much as 14 GtCO2 emission reductions with 100% renewable electrical energy sources—nonetheless inadequate to bridge the mitigation hole.

  • Solely a mix of possible stringent insurance policies on gas financial system (20% discount in new typical automobile common gas consumption between 2019 and 2050) and on weight and dimension (25% discount in new automobile common weight between 2019 and 2050) along with 100% renewable electrical energy may bridge the mitigation gaps.

  • Underneath a business-as-usual LDV fleet and present insurance policies, as much as 351 million EVs would have to be on the street within the US in 2050—as much as 90% of the on-road LDV fleet—to stay on course. Attaining this EV penetration would require a 100% market share of EVs (or as much as 28 million EVs) by 2050, or probably as early as 2035.

  • EV deployment in line with a 2 °C goal below present insurance policies could be even increased than the present, most optimistic, deployment targets. This brings up the vital challenge of what the related infrastructure and materials wants could be.

  • A fleet of 350 million on-road EVs in the USA may suggest an annual electrical energy demand of as much as 1,730 terawatt hours (TWh)—equal to 41% of the 2018 annual nationwide electrical energy era (4,200 TWh in 2018). Not solely would electrical energy demand enhance however the form of the demand might be altered considerably.

  • A excessive stage of EV deployment would require coordination between the EVs and their driving/charging behaviors. This coordination necessitates in depth deployment of the suitable charging infrastructure and tailor-made incentives to regulate driving/charging behaviors, resembling good contracts between EV drivers and electrical energy suppliers.

    It’s subsequently essential that EVs are built-in inside a broader framework to make sure that their deployment reduces CO2 emissions with out inflicting technical instability to energy methods. It will come at the price of deploying a considerable amount of renewable-based electrical energy, ‘good’ infrastructure and behaviors.

    —Milovanoff et al.

Lastly, there are technical challenges to do with the availability of vital supplies, resembling lithium, cobalt and manganese for batteries. With out drastic modifications to EV battery materials composition or main enhancements to the recycling processes of the used batteries, as much as 5.0, 7.2 and seven.8 Mt respectively of lithium, cobalt and manganese would have to be extracted between 2019 and 2050 for the US LDV fleet alone—8% and 29% of the recognized world terrestrial assets of lithium and cobalt in 2019.

Assembly CO2 budgets would require a transfer from technology-oriented insurance policies to activity-oriented insurance policies to supply higher substitutes for LDVs, resembling transit-oriented land-use insurance policies, deployment of latest public transport choices, progressive taxes on gas, parking, congestion and street use, and subsidies for public transportation. Pursuits in autonomous autos or ride-hailing needs to be scrutinized, as it’s unclear whether or not they would cut back or enhance automobile kilometres travelled, and investments in such applied sciences mustn’t come on the expense of public transit growth and efficient methods to cut back CO2 emissions.

‘Car’ is, nonetheless, a byword for independence and alternatives, and decreasing its use creates challenges for social growth. Tackling local weather change will not be a one-country, one-sector or one-technology job. Will probably be the achievement of intensive system-based evaluation, thorough planning and efficient implementation. EVs supply an distinctive alternative to cut back CO2 emissions. However electrification will not be a silver bullet, and the arsenal ought to embrace a variety of insurance policies mixed with a willingness to drive much less with lighter, extra environment friendly autos.

—Milovanoff et al.


  • Milovanoff, A., Posen, I.D. & MacLean, H.L. (2020) “Electrification of light-duty automobile fleet alone is not going to meet mitigation targets.” Nat. Clim. Chang. doi: 10.1038/s41558-020-00921-7