Without switch to green energy, EVs can increase CO2 emissions in MMR by 7%-26%
Introducing electric vehicles (EVs) in the Mumbai Metropolitan Region (MMR) without adopting sustainable modes of generating electricity may lead to a 7% to 26% increase in carbon dioxide (CO2) emissions by 2050, finds a recent study by researchers at the Indian Institute of Technology-Bombay (IIT-B). On the other hand, switching to greener modes of electricity generation can bring carbon dioxide emissions down by 27% to 41%.
The study by Deepjyoti Das, Pradip Kalbar and Nagendra Velaga was published in the peer-reviewed Journal of Cleaner Production on May 1. Das is a PhD scholar at the Centre for Urban Science Engineering (CUSE), Kalbar is an assistant professor at CUSE and Velaga is an associate professor in the Department of Civil Engineering of the institute.
They found that transport carbon dioxide emissions can rise significantly if EVs continue to be charged with electricity generated from fossil fuels. “EVs can be a better solution than internal combustion engines (ICE) if the major fraction of the electricity used to charge the batteries is produced from renewable energy and there is minimal transmission and distribution loss in the grid,” said Das.
As part of the Paris Climate Agreement (COP21) in 2015 to limit global temperature rise to well below 2°C, India has committed to reduce its carbon emissions by 30% to 35% by 2030. This commitment is part of India’s Intended Nationally Determined Contributions (INDCs).
With a 2030 target of replacing at least 30% of new vehicle sales by EVs, the Central government is driving policies that encourage use of EVs. Some policies include incentives under the Faster Adoption and Manufacturing of Hybrid and Electric Vehicles (FAME) scheme supported under the National Electric Mobility Mission Plan as well as income tax exemption and GST reduction from 12% to 5% for EVs.
Researchers at IIT-B estimated the contribution of EVs in reducing carbon dioxide emissions and fulfilling emission targets of 2030 and 2050 in 11 different scenarios. They sought to answer four questions: Will MMR achieve the 2030 and 2050 emission targets stated in the INDC by continuing existing policies? To what extent can EVs help achieve INDCs and COP21’s targets under different scenarios? Which scenario will be justified for MMR in fulfilling 2050 targets? What is the extent of contribution resulting from decarbonisation of electricity grids and reduction in transmission and distribution losses of electricity in achieving these targets?
The base scenario considered for the study is one where existing environment and transportation policies continue but without the introduction of EVs. In the remaining 10 scenarios, the researchers considered various levels of introduction of EVs, with green energy and transmission and distribution losses in electricity grids accounted for.
As of 2018, carbon dioxide emissions from passenger transportation were at 2.2 million tonnes. If existing policies are to continue without the introduction of EVs, the cumulative passenger transport sector’s carbon dioxide emissions in MMR can reach 160.97 million tonnes by 2050. Introducing EVs, that account for 30% of all vehicles, can drive carbon dioxide emissions up to 172.4 million tonnes. Replacing all vehicles with EVs can further increase emissions to 202.18 million tonnes, the study found. Minimising transmission and distribution losses in electricity grid will result in additional 1%, 2%, and 5% reductions in carbon dioxide emissions.
“The policy of pushing adopting EVs appears to be based on the global image of EVs being a green and environment-friendly option. The image on one front is justified as EVs have zero tailpipe emissions, which will help reduce air pollution from urban areas. On the other hand, if reducing total emissions from the transportation sector and reaching the COP21 target is concerned, then promoting EVs may not yield the best results for India,” said Kalbar.
This is because EVs are charged using electricity grids, which are primarily coal-based. “So even though EVs have zero tailpipe emissions, overall carbon dioxide emissions are higher. A parallel focus is required to accelerate the increase in share of renewable energy in the energy sector and minimise transmission and distribution losses, which currently account for 20% to 25%,” Kalbar added.
However, switching to renewable energy and reducing transmission and distribution losses, can bring down emissions by 27% to 41%.
Darpan Das, a postdoctoral fellow at the John Hopkins University who was not a part of the study, said the methodology of the IIT-B study can be used for estimating regional transportation sector’s carbon budget. “There are very limited studies carried out in India which focus on the methodology to estimate regional sectoral carbon budget from global carbon budget. The present study is an important attempt in this aspect, where researchers deploy this methodology in MMR region’s transportation sector to estimate the carbon budget in different scenarios. The findings indicate that with existing technologies, MMR will miss the national carbon budget by 55%-250%. EVs alone will not be sufficient to meet the targets,” said Darpan.
Pawan Mulukutla, director of Electric Mobility - Sustainable Cities at the Indian chapter of World Resources Institute, said the study focuses on the need for charging stations for EVs that use renewable energy. “It is absolutely correct that EVs, in isolation, may not have as big an impact on emissions. A comprehensive effort to move towards renewable energy and adopting EVs will give us the best results. In urban areas, a switch towards public transport will also help reduce emissions,” he said.
While the need to switch to clean energy grows simultaneously as EVs find greater acceptance, setting up infrastructure for the same might take time. “The cycles of technology transition are different for transportation and energy. For transportation, it is happening faster. One regulatory push for reducing emissions in urban areas can be to have charging stations that use renewable energy,” said Mulukutla.
Apart from public transport, IIT-B researchers also suggest alternatives such as improving fuel efficiency of ICE vehicles. By improving ICE vehicle’s efficiency by 20% to 40%, a significant reduction of 12% to 24% in emissions can be achieved by 2050.
While the study estimates carbon dioxide emissions, it does not take into account other harmful emissions from internal combustion engine vehicles such as carbon monoxide, nitrogen oxides and sulphur oxides. “The health and social benefits of EVs that do not emit these harmful pollutants are not considered in the study,” Mulukutla added.
“With our study, we are trying to highlight the cascading effects of adopting EVs without proper planning. More comprehensive studies can be done to understand other aspects of EVs. A comprehensive policy for urban mobility for each city or region needs to be developed,” Kalbar added.