Gross carbon emissions from alternative transport fuels in India

Abstract

The objective of the paper is to present a life-cycle assessment of pollution from alternative transport fuels in Indian conditions. The present study is limited to gross carbon emission (as CO 2 ) because of its serious implications for global warming. Indicative values of gross carbon emissions from bioethanol, CNG and electrical energy sources have been evaluated from industrial data and compared with those from oil. The energy and environmental analyses of bioethanol production in India show that bioethanol can significantly reduce global CO 2 emissions and, if used as a petrol blend, can help reduce oil imports as well as aromatics pollution from unleaded petrol (now introduced into India). The method used in this research has two main components. The first is an examination of each energy industry in detail, using primary sources of data from power stations, oil refineries and anhydrous ethanol production from molasses. The processes involved in each case are examined, taking into account energy use in any necessary auxiliary activities to evaluate the total carbon emissions. The second component is a detailed examination of one specific form of public transport. This is a three-wheeled 8-seater used in the city of Lucknow in North India. It is chosen because it is available with a petrol or compressed natural gas (CNG) spark-ignition engine (and hence could alternatively be ethanol-fuelled) and in a battery-electric version. Both parts of this data-gathering have been specific to the situation in India. In energy conversion the refinery crude composition and processes, basic resources of biomass and the mix of primary energy for electricity generation are different in each country. The types of vehicle used also vary considerably from region to region. It is observed that while CNG and electric-powered vehicles may have low and zero tailpipe emissions respectively, gross pollution from such vehicles and their associated resource systems may be significant. In the case of electrically-propelled vehicles the gross carbon emission is comparable with that for similar petrol-engine vehicles since about 80% of electricity production in India is fossil-fuel-based. In comparison, CNG shows a reduction of about a third. Alcohol-fuelled vehicles, by comparison, can show neutral (i.e., zero net) carbon emission. The importance of gross pollution assessments in rational choice of a fuel cannot be overemphasised.