Given India's reliance on coal, electric vehicles could at best be 10% more efficient than petrol in terms of CO2 savings.
In March, Delhi Power Minister Satyendar Jain announced that the city government would install 500 electric charging points at 100 locations under the first phase of its electric vehicle (EV) policy unveiled last year.
Besides the installation of an extensive city-wide network of EV charging points, the policy entails discounts for those buying electric vehicles and duty concessions.
The aim is to increase EVs’ proportion in new vehicle registrations to at least a fourth by 2024.
It is not the Delhi government alone that is gung ho about EVs.
In the Union Budget two years ago, the Centre had announced tax rebates, under Section 80EEB of the Income Tax Act, on up to Rs 1.5 lakh interest for people purchasing electric vehicles.
The rebates and subsidies are expected to push more people towards EVs.
While it currently takes two to four years to recover the extra cost of an electric vehicle, the Delhi government's policy would reduce the recovery time to one to three years.
But, if the objective is to save the environment, the government also needs to switch to a more efficient energy mix.
EVs would add only marginally to carbon dioxide savings if the country’s grid remains heavily reliant on thermal energy.
##Unlike conventional internal combustion engines (ICE), which run on petrol and diesel, electric vehicles have no tank-to-wheel emissions or tailpipe emissions, as these use electricity to convert energy.
However, given that these require charging from a power source, the well-to-wheel emissions need to be considered.
In cases where countries or states are more reliant on non-renewable sources, electric vehicles can be as polluting as, or only slightly less polluting than, ICE vehicles.
A 2015 analysis by Alternative Fuels Data Center of the US department of energy revealed that states that relied excessively on coal showed only a slight difference in annual emissions per vehicle when compared with states that used renewable sources of energy.
For instance, in the US, where 40 per cent of energy comes from natural gas and 20 per cent from coal, annual emissions from an all-electric car are equivalent of 3,774 pounds of carbon dioxide, whereas a gasoline vehicle emits 11,435 pounds of carbon dioxide-equivalent.
However, for West Virginia, where the energy mix is heavily dependent on coal, 88 per cent of the energy comes from coal-based power plants, the annual emissions from electric vehicles are 2.5 times higher at 8,945 pounds.
Add to this the fact that the carbon emission from producing an electric vehicle is higher than that from manufacturing an ICE vehicle, and there remains only a 16 per cent difference in overall carbon emissions between electric and gasoline-run vehicles.
Findings of a more recent study by the European Federation for Transport and Environment are also noteworthy.
Comparing the emissions from gasoline and electric vehicles in EU member states (including emissions during production), the study estimates 63 per cent CO2 savings across the EU member states for electric vehicles.
According to the study, while a petrol vehicle emits 253g of carbon dioxide per kilometre, an electric vehicle in EU27 member states emits just 99g per km.
The estimates are based on people driving a mid-sized car with an average of 13.3 km per litre for 15,000 km annually and an electric vehicle with a battery efficiency of 17.5kwh for every 100km with the battery produced in China.
Over its lifetime (estimated at 15 years), the Transport and Environment model assumes that a petrol vehicle would emit 57 tonnes of CO2, whereas an electric car would emit 22.4 tonnes.
##However, it should be noted that there is a wide variation among the EU states.
Sweden, which relies entirely on renewable sources of power, shows 79 per cent CO2 savings, but in Poland, where coal power generation accounts for 72 per cent of the energy mix, the savings reduce to just 29 per cent.
Now, contrast that with India, where the energy mix has 75 per cent coal and 4 per cent natural gas.
Extrapolating the results from an EU study and using IPCC data to compute the carbon emissions from the energy mix, calculations by Business Standard based on CEA data indicate that there will be only marginal carbon dioxide savings with the adoption of electric vehicles.
While the gasoline vehicle emits 253g of carbon dioxide per km, an electric vehicle in India would emit 235 gm of carbon dioxide — only a 7 per cent CO2 saving.
If the fuel efficiency of a gasoline vehicle rises to 15 km per litre, it would emit only 227 gm of CO2 and would be more efficient than an electric one.
And, if the fuel efficiency rises to 19km per litre, which is the case with most sub-compact cars — these are in a majority in India — the petrol car would turn 23 per cent more efficient than an electric car.
However, there has been a drastic improvement in the efficiency of electric cars as well.
The EU assumes a battery efficiency of 17.5kwh for 100 km, Tata's Nexon EV promises a 312-km range for 30.2 kwh, which translates into 10.4kwh for 100 km range.
If 18.5 per cent transmission and distribution losses are taken into consideration (all-India average), along with a 20 per cent reduction in range (the reported mileage for EV is 250 km on a single charge), the total carbon dioxide emissions come to 163 g — still only 10 per cent more efficient.
While these calculations are based on global grid averages, lower efficiency of Indian plants could further lower the savings.
##Much like the EU, there is a wide variation between states and regions across India.
While Delhi would witness a 13 per cent CO2 savings based on the above assumptions of better fuel and electric efficiency, Haryana, where the grid is more reliant on coal energy, would see only a 4 per cent saving.
In Uttar Pradesh, an electric car and a gasoline vehicle would produce the same amount of carbon dioxide.
According to the Central Electricity Authority (CEA), 89 per cent of the energy comes from coal power plants.
The worst-performing state Chhattisgarh, where a petrol-run vehicle would turn out to be 6 per cent more efficient than an electric car.
The case with Jharkhand and West Bengal would be similar.
While the Northeast will have the highest carbon dioxide savings from electric vehicles (36 per cent), followed by the southern and northern region, the eastern and western regions would fare the worst in terms of savings from EVs.
In case the electric charging points are powered by solar energy, the efficiency gains would be a whopping 67 per cent.
So, if EVs are to bring any meaningful environmental benefits, there would be a dire need to change the electricity mix in the country.
Image used for representation purpose only.
Photograph: Fabrizio Bensch/Reuters