It will take a bagful of cash and unlimited drive to bring out a fuel change for KSTRC buses from diesel to compressed natural gas (CNG).

A string of measures, including a CNG-friendly policy, will have to be adopted by the government before flagging off the project.

Making bus engines compatible with CNG would require heavy investment, as each bus would incur a cost of about Rs.4.5 lakh, according to experts. This is in addition to the investment on setting up CNG filling stations and training to be given to employees on handling the gas and maintaining buses.

Establishing infrastructure that could be utilised by other agencies would help KSRTC recoup the initial investment, said Alex P.Varghese, a former executive of Indian Oil Corporation and an expert on natural gas technology. To start with, a policy conducive to conversion of petrol car engines to CNG-enabled ones is expected to go a long way in ensuring the success of the CNG programme in the State.

Yash Arora, who runs a business in the import and fitting of CNG-enabled engines in New Delhi, told The Hindu over phone that the CNG experience in New Delhi has been quite satisfying. Over 10,000 buses, 70,000 cars, 65,000 autorickshaws and 25,000 taxis were using CNG fuel. There were hitches during the initial stage but the problems were ironed out later. Over 250 refilling stations cater to the CNG vehicles in New Delhi and the large queues witnessed in the beginning have waned now.

The conversion kits for cars, imported mostly from Italy, cost Rs. 25,000 to Rs.65,000. Petrol car engines are converted to function on CNG to cash in on difference between prices of petrol and CNG. CNG costs around Rs. 40 per kg and the vehicle gets mileage more or less the same as that of petrol car.

One of the most comprehensive studies on the induction of CNG engines was conducted by the Economic and Social Council of the United Nations. The report discusses the pros and cons of the CNG experience.

City buses operating from a depot on fixed itineraries are ideal for conversion to dedicated CNG combustion engines. In that case, the diesel engine needs to be modified to a spark ignition engine in order to burn 100 per cent natural gas instead of diesel. In the case of new vehicles, a regulated 3-way catalytic converter should be included. From the environmental point of view, a gas engine with a regulated 3-way catalytic converter would be the most promising solution to achieve emission reductions of more than 90 per cent for all relevant pollutants. The emission of soot does not occur in CNG operation. Bad smell from unburnt fuel is considerably reduced.

To develop an efficient strategy for the promotion of CNG as a substitute for diesel fuel in road transport, it is necessary to assess the market potential. Planning and implementation of concrete measures for the conversion, as well as an assessment of environmental and economic impacts would be required.

The fuel consumption for buses and trucks is very high. These classes are the largest consumer groups of diesel. Buses and trucks, which operate primarily in or around urban centres, will have better access to refuelling facilities than those operating on long distance, inter-urban routes. These facilities may be public CNG stations or privately owned facilities servicing a fleet. In general, buses which operate along defined routes and, at least once a day, return to their depots are ideal for the conversion. Their access to gas is therefore better than that of trucks which tend to have more diverse operational patterns.

The principal driving force in the development of a CNG market is user economics. There must be sufficient direct savings in operating costs for vehicle operators to consider changing from diesel vehicle operation to a ‘new fuel’. The essential requirement for the development of a market through fuel cost savings is a sizeable difference between the price of CNG and that of diesel to attract vehicle operators.

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