Implications on Costs and Emissions of Electrification of Public Transport Buses

By Suvedh Jaywant

The urban transport sector in India currently faces the challenges of increased travel demand and trip lengths with a decrease in modal share of public transport (only 7% in India as against 30-35% in most of the countries) and increased private vehicles on roads (number of registered private vehicles in Indian cities is increasing by around 12% every year). This has resulted in an increase in traffic congestion issues, alarming levels of air pollution (concentration of PM10 in cities like Delhi is twice the WHO prescribed levels whereas that of PM2.5 is 17 times in Kanpur) and increase in related health problems (right from irritation in eyes and respiratory disorders to miscarriages and improper development of a child’s brain) , energy security issues due to higher energy demands by this oil dominated sector and rising green-house gas (GHG) emissions contributing to climate change. A new approach is needed to deal with these issues which involves decongestion of roads by promotion of public transport along with moving to a cleaner source of energy. Major cities in the world are looking at using electric buses for public transport as one of the probable solutions to address these issues. However, the electric buses are highly capital intensive as per today’s market conditions and a thorough analysis of the implications of having electric buses for public transport in an Indian scenario is required.

Most of the studies conducted so far have considered the indirect costs on health and pollution (which are notional) to check the viability of the electric buses and this study thus conducted a monetary cost-based analysis of having electric buses without considering the notional costs to understand the financial burden on the citizens using the public transport. The findings are applicable for Indian scenario in general.

For this analysis, a case study of the Pune Mahanagar Parivahan Mahamandal Limited (PMPML), which is the municipal bus transport utility in Pune city was done. In Pune, the modal share of public transport was 18% as per the 2011 census which has been reducing continuously with the number of registered vehicles at 3.7 million for a population of 3.5 million in the year 2018. A study conducted by Shakti foundation in 2017 stated that the concentration of P.M 2.5 for Pune was 56.3 ± 12.9 μg/m3 which is much higher than the national standards (40 μg/m3 ) and five times that of the WHO guidelines (10 μg/m3 ) with 24.1% of these pollutants being the emissions from the transport sector. PMPML has an ambitious target of inducting 500 new-technology based fully electric buses in its fleet to tackle the issue of air-pollution in the city. It becomes necessary to evaluate the cost implications of this decision and the extent of the potential contribution of this move to mitigate pollution and emissions. The cost per kilometre (CPK) for different types of buses has been calculated for the city of Pune using the Total Cost of Ownership model and the current operational constraints based on costs of the current bus fleet of the PMPML.

The Table below shows the CPK for different bus variants at Business as Usual (BAU) scenario which tells us that it is already viable to use battery operated pure electric buses instead of pure diesel and hybrid buses in the AC bus segment. But overall, the CNG buses are still far cheaper as compared to electric buses.

Type of Expense Unit Diesel Non-AC CNG Non-AC Diesel AC Hybrid AC Electric AC Electric Non-AC
CapEx Lakh Rs ₹ 58.40 ₹ 84.00 ₹ 122.40 ₹ 235.15 ₹ 272.51 ₹ 247.40
OpEx Lakh Rs ₹ 623.04 ₹ 563.12 ₹ 779.70 ₹ 621.44 ₹ 529.29 ₹ 502.57
TCO Lakh Rs ₹ 681.44 ₹ 647.12 ₹ 902.10 ₹ 856.59 ₹ 801.80 ₹ 749.97
PV of TCO Crore Rs. ₹ 353.09 ₹ 343.30 ₹ 490.33 ₹ 503.25 ₹ 451.29 ₹ 422.51
CPK at PV of TCO Rs./km ₹ 39.34 ₹ 38.25 ₹ 54.63 ₹ 56.07 ₹ 50.28 ₹ 47.07

Further, if only operational expenditure is considered, the AC electric buses are cheaper than non-AC CNG buses by around 11.5% at BAU scenario which would further be cheaper once the battery rates go down.

The table below shows the tail-pipe emissions mitigated from this shift. It is indisputable that the electric buses will provide a clean local environment, but the net mitigation in carbon emissions is presently limited due to the coal dependent electricity.

Type of Bus CO Emissions
(Kg / year)
THC Emissions
(Kg / year)
NOx Emissions
(Kg / year)
PM Emissions
(Kg / year)
Diesel Non-Ac 351.51 30.46 93.74 2.34
CNG Non-AC 237.86 29.70 172.41 1.80
Electric Non-AC 0.00 0.00 0.00 0.00
Diesel AC 562.42 48.74 149.98 3.75
Hybrid AC 224.97 19.50 59.99 1.50
Electric AC 0.00 0.00 0.00 0.00

The cost break-up of electric buses shows that 22% and 12% of the TCO was the capital cost and battery replacement cost respectively with more than 8% as the interest costs, which was huge as compared to 10% of TCO as capital cost and 2% as interest cost of Diesel buses.

Suvedh 1

If the battery rates come down as speculated, the lower cost of battery replacement would bring down the CPK of electric buses by ₹3 and availing interest free loan can further bring down the CPK by ₹3. The CPK of an AC electric bus would then be ₹4 more than that of a Non-AC CNG bus, and thus comparable. 

It was further found that AC electric buses would be at parity with non-AC CNG buses around 2023. If the CNG rates increase faster than expected or if capital is available at a lower rate of interest, this breakeven can happen earlier, or vice versa if the battery and bus prices do not come down as projected. Also, more GHG emissions can be mitigated if the share of renewables in the electricity is increased and possibilities of other innovative technologies like top-up charging using solar roof-top and opportunity charging are explored. This shows that the viability of electric buses in the future looks better than the present.

However, to replace all the existing buses by electric buses in a single year in 2023 will not be feasible as this will lead to huge financial burden on PMPML in a single year, and some of the buses need to be replaced even before 2023 as they complete their 12 years of life. Thus, a phase wise replacement of the existing fleet is suggested based on the age of the buses. 

The high capital costs of electric buses are compensated by low operating costs as compared to diesel and CNG buses. But the benefit of low operating cost of the electric buses can be reaped only when the buses are able to run for the scheduled kilometres every day unlike today’s case where the scheduled trips are not completed due to the traffic congestion. Having electric buses in Public transport is just one of the components of the multi-dimensional solution that is required to make the urban transportation clean, affordable, and reliable in the country, which needs to be accompanied by the larger practice of changing the way cities and transportation systems are planned.

Thus, this study goes beyond using the notional costs of emissions and health of the citizens in order to check the viability of electric buses in the municipal transport fleet and finds out that having electric buses is not financially viable presently but looks promising in the future. It is recommended to have air-conditioned electric buses in the fleet of municipal transport buses in order to mitigate the carbon emissions, have a clean local environment, enhance the comfort of the passengers using public transport, and increase in the modal share of public transport in Indian cities. Innovative financing mechanisms need to be explored to reduce the financial burden of the high capital cost on the transport undertakings or the citizens using public transport, till the electric buses become financially viable. Else, it would just be a replay of  the international situation of inequitable sharing of the mitigation burden (where citizens using the Public Transport have to bear the costs of cleaning-up the environment) that the Government of India so vehemently opposes at the climate change negotiations internationally.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s