Time for intervention: What do the mitigation scenarios look like for India’s road transport emissions?

Electrification Tracking progress
Clean air
Emissions modeling

The third in a blog series focused on our meta-study of India’s road transport emissions analyses.

With the previous blog, which analyzed the Business-As-Usual (BAU) scenarios, we saw clearly that a “no-intervention” future is a non-starter that could easily lead to a tripling of CO2 emissions from road transport in India by mid-century. Therefore, we focus here on the scenarios that incorporate policy interventions that could help decarbonize the sector. Besides the BAU, there were typically two kinds of alternate scenarios incorporated in the models we analyzed: the Moderate effort and the High Ambition. The table below describes the scope of these scenarios, as defined by the respective modeling teams.

Table 1. Description of mitigation scenarios
Modeling team Moderate High Ambition
Sustainable Growth Working Group (SGWG)a: CEEW, PNNL, CSTEP, TERI, and IRADe Supposes that policy targets, as announced by the Government of India, are fully effective [called New Policy scenario] Considers success far exceeding that envisioned in policy targets set by the Government of India
ICCT Includes moderate effort above and beyond existing adopted policies Incorporates ambitious decarbonization policies aligned with state-of-the-art policies adopted around the world
IEA Incorporates policy ambitions and targets that have been legislated for or announced by the Government of India and by other governments around the world [called Stated Policy scenario] Under this scenario, India is on track to reach net-zero emissions in the mid-2060s [called Sustainable Development scenario]
(a) The five modeling teams worked together on an inter-model comparison study organized as part of the SGWG under the aegis of NITI Aayog. Hence, these teams share some of their assumptions and interventions. The findings of this work were released in 2019.

The goal of our meta-study is to identify nationally determined contribution (NDC) targets for the road transport sector, and thus we will discuss only the High Ambition scenarios, as these align closer with a 1.5°C path. The scenarios consider different policies and interventions, including efficiency improvement, electrification, diversification of fuel, travel demand reduction, and mode shift to public transport. Efficiency improvement and electrification were found to be the most effective interventions for reducing emissions across models.

Assumptions with regard to how each of these different policies would take shape in the future vary immensely, and Table 2 provides an overview of the different interventions taken into account in the High Ambition scenarios of different models. For instance, PNNL, TERI, and IRADe expect significant electrification in two-wheelers and three-wheelers (2&3W) by mid-century, while freight vehicles are expected to continue relying on petroleum. IEA and ICCT also expect 2&3W and passenger light-duty vehicle sales to electrify almost entirely by mid-century, although IEA’s precise estimates are not available. ICCT’s High Ambition scenario includes significant electrification in the bus and freight segments, too, and considers electrification along with simultaneous decarbonization of the electricity grid.

Table 2. Interventions considered by the modeling teams in their High Ambition scenarios (for 2050, unless otherwise specified)
Modes SGWGa ICCT IEA (all for 2040)
Electric vehicle share of new vehicle sales
2W 80% 100% Not available
3W 100% 100% Not available
Passenger light-duty vehicle 30% 100% 90%
Bus 40% 95% Not available
Light-duty truck 0% 100% Not available
Medium-duty truck 0% 90% Not available
Heavy-duty truck 0% 90% Not available
All Not available ~100% 86%
Efficiency improvements
Annual reduction 1.8%–2.7% between 2021 and 2030 1%–3% between 2021 and 2050 Not available
Biofuel blending levels
Bioethanol in gasoline 20% 20% Not available
Biodiesel in diesel 5% 5% Not available
Travel demand management
Reduction in vkm -15% till 2030;
-20% till 2050 from 2015 levels
Not considered Not available
Alternate fuel
Fuels diversity Electricity, compressed natural gas (CNG),
biofuels, liquefied petroleum gas (LPG)
Electricity, CNG, biofuels Electricity, CNG, biofuels, hydrogen
(a) The policy interventions for CEEW, PNNL, CSTEP, TERI, and IRADe were formulated under the SGWG. These assumptions only represent the highest ambition and not all interventions were adopted across all of the models. For instance, no electrification was considered by CEEW and CSTEP under their High Ambition scenarios.

Notice that efficiency improvement assumptions also vary across models. While ICCT expects efficiency improvements to continue until mid-century and at a greater pace, CEEW, PNNL, CSTEP, TERI, and IRADe presume that efficiency improvements cease after 2030. In terms of fuel diversification, most models consider only electricity and CNG to play any noteworthy role. Biofuel blending also plays a role, meeting more than 5% of road transport energy demand in 2035 in ICCT’s High Ambition scenario. However, biofuels constitute a fraction of shares of gasoline and diesel that will decline over time, anyway; for that reason, they aren’t especially significant in a 2050 time frame, and are catering to less than 2% of road transport demand by 2050. Other fuels like hydrogen or even LPG would remain almost inconspicuous in consumption.

However, we would like to point out that the latest projections by IEA under the India Energy Outlook 2021 expect CNG, electric hybrid, electric, and hydrogen vehicles to constitute only around 50% of the freight vehicle stock by 2040; the other half would still be diesel. In the case of ICCT, around 40% of the freight vehicle stock would be electric or CNG vehicles in 2040. Electric trucks occupy bulk of this share, around 35.6% of all freight vehicles, and only 2.1% would be CNG. By 2050, ICCT projects that around 70% of the freight vehicle stock would be electric, and the rest diesel.

In the figure below we plotted CO2 emissions from the Moderate and High Ambition scenarios. Emissions from the High Ambition scenarios are, of course, lower than the moderate effort scenarios. We can also clearly see two different types of emissions pathways across models within the High Ambition scenarios: One expects emissions to continue to grow until mid-century, although at a slower pace in comparison to the BAU, and the other expects these trends to reverse.

Figure 1. High Ambition versus Moderate effort trajectory for CO2 emissions across models.

Models like ICCT and IEA expect emissions to peak by 2030. IRADe’s scenario also expects peaking to happen, but a decade later. These trends show that reversal of ongoing emission trends in the road transport sector is possible with an identified set of decarbonization strategies. IEA, ICCT, and IRADe’s emission trajectories show that it would be possible to bring down emissions in 2050 to the same level as it was in 2020 or even lower. Some High Ambition emissions trajectories show that COsub>2 emissions could lower to approximately 250 million tonnes (Mt) in 2050, but others show that if we fail to arrest the current upward trend, emissions could easily shoot beyond 600 Mt. These two extremely divergent trajectories reflect the need to implement the most ambitious mitigation efforts, if any serious decarbonization of the road transport sector is desired.

The share of emissions from freight vehicles is higher in High Ambition scenarios than in the BAU scenarios across all models. Further slicing emissions by vehicle category shows that heavy-duty trucks could be responsible for over half the emissions in 2050. On the other hand, owing to electrification, emissions from 2&3Ws would become negligible, contributing a miniscule 1%–7% in 2050.

In terms of energy consumption, the average across models in the High Ambition scenario is about 6–7 exajoules (EJ) by 2050. Energy consumption is expected to roughly double between 2020 and 2050, whereas in the BAU scenario, the energy demand was almost tripling or even quadrupling in some cases. As shown in Figure 2, the models with conservative electrification and efficiency improvements foresee liquid petroleum to remain the primary energy source for road transport. Meanwhile, in the models with the most aggressive electrification and efficiency improvement interventions, electricity could meet as much as 40% or even 70% of the energy requirement of the sector by mid-century. As per most of the models, CNG would be the other prominent fuel and would be used to mostly power buses by 2050. CNG could be, at best, fulfilling 20%–25% of energy demand in 2050.

Figure 2. Energy consumption by fuel under the High Ambition scenarios across models. Note: In models other than ICCT, the liquids fuel category may include some degree of biofuel blending in liquid petroleum.

Here we would like to highlight that some of the models with conservative electrification assumptions framed these scenarios a while back (mostly under the SGWG exercise in 2018–19 or earlier). It is very much expected that many of these models would update their assumptions on multiple fronts. The expectation with respect to electrification could especially rise across models in the wake of the positive developments in battery price reduction, the introduction of multiple electric vehicle models, the emergence of new business models, and the launch of central and state electric vehicle subsidies and incentive policies. Indeed, only IEA’s numbers are recent enough to incorporate the COVID-19 pandemic. It’s very likely that many of the models would now incorporate higher optimism with respect to policies like travel demand reduction and higher mode share in favor of public transport. While higher public transport use might sound counterintuitive in the backdrop of the ongoing pandemic, it’s possible that people might not wish to own private vehicles if they no longer need to commute daily, and this could induce a shift toward public transport, especially among the younger population. These revised assumptions would certainly further reduce energy and emissions from the sector.

Even though energy use and emissions drop significantly in the High Ambition scenarios, and some models expect emissions to peak in a decade, they show that road transport would still remain far away from carbon neutrality by mid-century. That leaves a lot more to be done in terms of thinking about the policies and interventions that could more rapidly decarbonize the sector. In upcoming blogs we will further deliberate upon the policies and interventions that could lead to this rapid decarbonization, including and especially electrification. So, watch for those in the coming weeks!

This project is part of the International Climate Initiative (IKI). The Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) supports this initiative on the basis of a decision adopted by the German Bundestag.