Plug-in Hybrids for Public Transport - Benefits and Impacts

Emission reduction and fuel economy are the primary drivers for public transport authorities. Electric propulsion is efficient, and do not produce any local emissions. However, achieving range similar to IC engine vehicles would require large battery pack, and considering this plug-in hybrid technology may be attractive options for public transport buses. Advances in battery technology and power electronics have enhanced the possibility of plug-in hybrid vehicles penetrating market in near future. Rising fuel prices and concerns over green house gases as well as other emissions have made it essential to consider such options seriously. Globally there are many efforts towards development of plug-in hybrid vehicles and Indian vehicle manufacturers have also demonstrated plug-in hybrid buses. Such vehicles can offer higher benefits in Indian congested traffic. However, it is required to evaluate the comparative environmental performance of plug-in hybrid vehicles in life-cycle analysis. It is also essential to evaluate the impact on grid, and the charging infrastructure required. This paper attempts to quantify the impacts of introduction of a fleet of plug-in hybrid buses in Delhi. Estimations are made on the benefits achievable in terms of emission reduction, and additional electric power demand for charging the vehicles. While comparing the benefits of plug-in hybrid vehicles with conventional IC engine vehicles, life cycle emissions are calculated. The charging infrastructure required is also briefly discussed. The impact on electricity grid and the required infrastructure depend on the charging pattern. Various charging scenarios are considered to find the impact on the peak demand of the power grid.