In India, transportation sector emissions is a significant contributor to the deteriorating air quality and human health in cities. Transportation accounts for 20 per cent of global energy use and it contributes 25 to 30 per cent of the emissions. With the rapid acceleration of the Indian automobile markets, battery-powered electric vehicles (EVs) represent a promising pathway towards improving air quality, energy security (avoiding oil imports) and economic opportunities. The gradually increasing momentum behind EV adoption – both from the side of the government and the automotive industry – will ensure that electrification of transport sector will play an important role in Indian mobility going forward nurtured by policy support from the government. To accelerate adoption of EVs, a recent study by India Smart Grid Forum qualitatively and quantitatively assessed the potential for electrification of public transport in Kolkata.
With India’s plans for aggressive de-carbonization of electricity generation, EVs provide an unique flexibility resource for vehicle-grid-integration (VGI) capabilities that can be used to address variability from renewable generation resources. To leapfrog India’s roadmap to extend policy objectives toward accelerated deployment of EVs, this study qualitatively and quantitatively assesses the feasibility of electrification of public transportation for Kolkata with emphasis on buses, three-wheelers and ferries. The high-level feasibility analysis of electrification of publicly-managed taxi fleets, shared vehicles, and trams was also conducted. The electricity distribution system and urban transport practices for Kolkata were reviewed to propose an accelerated and practical implementation plan to deploy EVs into Kolkata’s public fleets.
Recently, Kolkata has been chosen for the study, as it was the first city in India that introduced public transportation system running on electricity and represents a unique opportunity to leverage the electricity infrastructure for accelerated and cost-effective EV deployment. The city also has taken steps to prepare a roadmap for transitioning the city to low-carbon future. CESC Kolkata, the first electric utility in the country, is successfully supporting the tram system network with supply of power through 6 kV AC, which Calcutta Tramways Company (CTC) converts to 550 volt (V) DC at their receiving points and 550 V DC (about 400 amps during peak load) is fed on the tram network.
From 1899 until 2008, CESC also used to supply DC power to several residential and low tension industrial customers at 225 V and 450 V through a three-wire DC distribution system, which has now been phased out. With expansion of the city over the years, the lion share of public transportation has moved from the trams to buses, three wheelers and cars.
According to the World Health Organization (WHO), Kolkata is also the 12th most populated city in the world, and lists third among the Indian urban cities. Electrification of public transport will represent one of the most promising pathways to increased energy security and improved air quality in the city that retains Kolkata’s spirit of electrification of public transportation.
Since Kolkata has a unique situation where DC power is available, it is easier to set up DC Fast Charging (DCFC) stations for public transport vehicles. DCFCs are more conducive for fleet operations as it can also support taxi and mini-bus fleets efficiently. Currently in India most of them are on low voltage platforms; and this contributes to the uniqueness that DCFC has with respect to low voltage vehicle platforms which perhaps has no parallel anywhere.
Fast-tracked rollout of charging infrastructure for fleet operations will prompt the automotive companies to come out with many variants of the 1-ton load carrier/ passenger vehicles, which are currently being developed/ prototyped or commercially launched by at least half a dozen Indian companies. Charging station network in Kolkata, which can be made scalable by utilizing the existing tram lines, gives serious potential for commercial/taxi/passenger vehicle fleets to develop over a short period as an economical proposition.
This technology intervention can change the paradigm, and EV introduction can jump-start. One aligned strategy could be to reduce the size of lithium ion battery packs for electric buses, which can give a range of 50-60 km in single charge and rely on this DC charging network extensively by design. Converting taxis/autos and buses to EVs in a planned (and organized) way would be the approach for this transition. This would potentially reduce about 50 per cent of the pollution generated by these vehicles, which for the most part are idling in stop-and-go traffic in their daily routines. Also, the distance traveled in a given day is not that large, which makes the conversion of public taxi fleet to EVs much more attractive.