=1 ~24062 E5TM. A^D THE WORLD BANK International Experience with CNG Vehicles N atural gas (NG) is a clean-burning alternative NG, and makes dual-fuel unsuitable if the objectivc is fuel with a significant potential for reducing to reduce emissions. harmful emissions, especially those of fine * Dedicated, which runs particles, from vehicles. Vehicular particulate emissions entirely on natural gas. Conversion of vehicles in turn are a concern, because they are small (small in poor condition, particles are especially harmful to health) and numerous. All the three types can be as well as poor and occur near oround level where people live and work. C, .* manufactured from the conversions, are two In response, some have argued for mandating NG as an start to use natural gas of tile most serious automotive fuel, most notably in Delhi. This note discusses by original equipment potential problems in where NG vehicle' programs have been successful, where manufacturers (OEM), developing country have they failed and why. or cities, and could Users of Natural Gas Vehicles (NGVs) * convertedfromvehicles even defeat the that were originally purpose of switching According to the information collected by the International manufactured to run on to natural gas. Association for Natural Gas Vehicles (IANGV) between gasoline or diesel only. August 2000 and August 2001. over 1.5 million vehicles run on NG worldwide fueling at more than 4.000 refueling Either way, there is an incremcntal cost relative to vehicles stations (Table 1), with 14 countries having 10,000 or more using conventional liquid fuels, and this additional cost has NGVs. By far the majority of NGVs are gasoline vehicles to be recovered from savings in operating costs, typically converted to CNG. lower fuel costs. For minimizing emissions. OEM vehicles are considered superior to converted ones, but they are Table 1: Top 5 NGV Markets [1] more expensive. In 1998, there were 43 OEMs around the world producing NGVs. Conversion of vehicles in Ctountr b I'hiek/s Refuvelling., sin tlOl% poor condition, as well as poor conversions, are two of i Aroennn,Li MA-x -49L the most serious potential problemiis in developing counitry lr:tIx 370,000 355 cities, and could even defeat the purpose of switching to natural gas. According to one estimate, 50 to 70 percent Pak i'Lanl 2I R1 U X) O200 of vehicles being converted in developing countties may Br.iil 120,000 131 fail a good pre-conversion inspection [2], with many United States 102,430 1,250 requiring rebuilt engines and other repairs for an effective \World total 1.7' 4 46.2 4A9 1 NGV program. Types of Natural Gas Vehicles Two Reasons for Switching to Natural Gas 1. ivrXg;..li.l f energy sources has been the In terms of fuel supply. there are three types of NGVs: 1. Diver,: [7. oti.'f e historical reason for selecting natural gas as a motor * Bi-fiel, where the vehicle can run on either natural fuel. In 2000, the ratio of proven reserves to production gas or gasoline. of natural gas was estimated to be 62 years, 63 percent * Duial-fuel, where the vehicle runs either on diesel only higher than and that of oil at 38 years [3]. or diesel and natural gas with the combustion of diesel 2. Muich loiter emissions. especially compared to used to ignite the natural gas. The stop-and-start nature conventional diesel vehicles. This is the primary reason of urban bus cycles limits the substitution of diesel by for switching from diesel to NG today. However, replacing diesel with natural gas makes sense only if At the same time, the diesel emissions have been confirmed to contribute emergence of the so-called Replacing diesel substantially to ambient fine particulate ..clean diesel," pilot tested in with natural gas concentrations the pollutant that represents the North America and Europe makes sense only greatest health hazard in urban air in the majority of and slated for mandatory if di emisi developing country cities. How to evaluate different deployment by the latter halff hies be n policyoptionsforvehicularairpollutionisdescribedin of this decade, may pose a have been an earlier briefing note [4]. challenige to the long-term coiifirined to future of NGVs. Clean diesel conitribute Advantages and Disadvantages of NGVs technology relies on dramatic substantially to reductions in the level of sulfur ambient fine The advantages of NGVs include in diesel fuel (sulfur content of particulate below 0.005% and preferably * very low particulate emi ssions cven below 0).01 %) to cnable concentrations. * low emissions of airborne toxins the use of such after-exhaust treatment devices as continuously regenerating particulate * negligible emissions of oxides of sulfur (SO) traps for reducing fine particles and lean deNOx catalysts for reducing oxides of nitrooen (NO). Limited available * more quiet operation, having less vibrations and less data indicate that CNG may not have measurable odor than the equivalent diesel engines. advantages over state-of-the-art clean diesel technology Their disadvantages are for particulate emissions (Table 3). * much more expensive distribution and storage Table 3: Comparison of CNG and * higher vehicle cost "Clean Diesel" Buses in New York, g/km [7] * shorter driving range Driving cycle Central business New Yorkbus 1 * much heavier fuel tank district cycle cycle Poilutant C'NG Clean CNG Clean * potential performance and operational problems Diesel Diesel compared to Liquiid fuiels [5]. Particulate matter 0.011 0.015 0.044 0023 With respect to emissions, it is worth noting that advanced NC) 15 16 32 45 technology gasoline vehicles with three-way catalysts are Zt . .Total hydrocarbons 10 0.01 42 0.038 so clean that the fuel itself (that is. whether liquid or gas) plays a relatively minor role. especially for the regulated None: Heavy-duty diesel buses (1999 model year) using diesel emissions. Under these circumstances, converting an containing 309 parts per million (ppm) sulfur and Johnson Matthey's advanced gasoline vehicle to gaseous fuel could even continuously regencrating particulate filter systcm (but not lcan increase, rather than decrease, emissions. deNOx catalysts): CNG buses (1996. 1998 and 1999 model year) equipped with oxidation catalysts. NGVs have a marked advantage over conventional diesels. Manv technical breakthroughs have been announced for Example data taken from the United States comparing the deployment of clean diesel, including refining processes compressed natural gas (CNG)withdiesel, shown inTable to produce ultra-low sulfur diesel at a fraction of the cost 2. amply illustrate this point, employing conventional technologies. But clean diesel is likely to be many years away for widespread application Table 2: Emissions Benefits of Replacing in developing countries. Today, natural gas remains the Conventional Diesel with CNG in Buses [6] only commercially proven clean fuel alternative for heavy- duty engine applications, with considerable implications Fuel CO NOI PA!i for investment in infrastructure. Diesel 2.4 g/km 21 g/km 0.38 g-km Two Contrasting Country Cases: CNG 0.4 g/km 8.9 g/km 0.012 g/km Argentina and New Zealand % reduction 84 58 97 Argentina and New Zealand were once two worldl leaders in the NGV market. Today. Argentina's rnarket remains Note: Medium-dutv diesel buses,. central business district test cycle. co carbon monoxide: NO oxides of nitrogen PM particulate matter the largest in the world. while New Zealand's NGV market g/km grams per kilometer. has declined precipitously beginning in the late 1980s. U Argentina [8] was so preoccupied with meeting the demand for conversion that quality at times became a secondarv Argentina launched its CNG vehicle program in 1984. c i By then, there was an extensive network of natural gas priority, resulting in the perception of CNG as a second- pipelines reaching most cities. The government offered rate fuel which was used only because it was much no subsidies, and instead the incentive for fuel switching cheaper than gasoline. stemmed entirely from the high tax on gasoline. The fuel When the new Labor Government began to deregulate prices in December 1999 were US$1.04 per liter of the economy, withdrawing financial incentives for the premium gasoline, US$0.50 per liter of diesel, and US$0.33 CNG industry, the NGV market essentially died. The per cubic meter (m3) of NG (or about US$0. 41 per NGVs today number about 10,000, a decline of 100,000 kilogram). At these prices, the payback period for those from the peak of 1 10,000. vehicle owners converting from gasoline to CNG could be a matter of months depending on the total number of Observations from Around the World kilometers (km) traveled a year (Figure 1). Most CNG vehicles are those converted from gasoline vehicles. Experience with natural gas vehicles * Poor conversions can lead to higher emissions, Figure 1: Payback for Conversion from operational problens, and even accidents, giving Premium Gasoline to CNG in Argentina, NGVs a bad name. When gasoline vehicles were 1999 Fuel Prices converted to NG, one of the unpleasant surprises in industrial countries was that the converted NGVs were 40 - found to be more polluting when tested for emissions 30 - in the case of recent model year vehicles. 25 - \ 20 a + High-usage vehic le fleets which can exploil t 1S economties of sc ale-in setting up refueling *~ 10 - infrastructure, staff training, vehicle maintenance and .n O f'uel purchase-are especially suited for NGVs. d 8 * A champion coordinating activities ainong different - m Y & to ts c CD stakeholder-s and puiblicizing the benefits of NGVs Annualkm traveled are especially useful in the early days of a NGV program. In contrast, there has been little conversion from diesel to CNG because the price difference between diesel and * Consistent reports of poor performance qf NG CNG is not sufficient to recover the incremental cost of buses mamtfactu red in the early 1990s suggest that * ~~~~~~~~~~~~NG buses were not only more expensive to purchase NGVs within a reasonable period. As a result, there are bus were not only more expensivet no CNG buses in regular operation today. and in fact diesel but were also about 30 to 40 percent more expensive IS actively competing with CNG to capture the taxi market tomianadhdcoserbyeuedelblt. away from CNG. While many of these problems are being overcome. heavy-duty NG engine technology still needs somc New Zealand [9r refinements. In stark- contrast to Argentina, the government of New * Successful NG bus programs are based on Zealand was heavily involved in the NGV program from dedicated OEM, and not converted. buses. the outset. It provided generous financial incentives both Conversion of existing diesel vehicles typically does for conversion and establishing refueling stations, so that not make happy customers. the number of CNG vehicles doubled every year, seriously * Transit bis operators in man7y, if not mosl, stretching the ability of the industry to cope. The industry developing countries are cash-strapped, partly on Box 1: Natural gas buses: Experience of Phoenix Transit, USA [5] The bottom line is training, training, and more training. Phoenix Transit initially met resistance from the operators, mechanics, fuelers and subsequently the union. They trained everyone from top management to bus washers. The main challenge is to have trained operators and maintenance staff that can observe and report changes in the buses while in operation and during preventive maintenance. The next challenge is to have bus manufacturers and component manufacturers working in partnership with the service and maintenance contractors. U account of fare controls. As a result, buses are not Note properly maintained, nor are the operators in a Natural gas vehicles (NGVs) canl be fueled by position to purchase more expensive NG buses, N compressed natural gas (CNG) or liquefied natural gas 'dol(e extensive trainmng to all their staff on this s &' provi I J.~~~~~~~~(ING), with the majority of NGVs being- CNG vehicles. new technology (see Box 1). and to accept the possibility of more repairs to deal with greater Ref frequency of bus breakdowns. High emissions from diesel buses are not merely because of the choice of 1. IANGV. 2001. "International Natural Gas Vehicle fuel, but are symptomatic of deeper problems, and Statistics," August, available at . to failure. 2. Impco Technologies. 2000. "Alternative Fuels Thte number of refueling statiotns and NGVs nmuist Presentation to the World Bank". presentation made bte balantced so that there are no unacceptably long at the Workshop on Compressed Natural Gas, 2-3 queues for refueling on one hand and under-utilization March. Washington DC. of filling stations on the other. During the early days 3 hp. 2001. hp Statistical Reviev of World Eunetgy of NGV programs, the government may consider Junwe 2001. June, available at . by granting permits where filling stations were not al]owed earlier (Argentina) or by providing subsidies 4. World Bank. 2001. "Vehicular Air Pollution; Setting Priorities." South Asia Urban Air Quality Management of I imited duratioin. D Briefing Note No. 1. October, Washington DC. Typical pre-conditions for success 5. Watt, Glen M. 2001. "Natural Gas Vehicle Transit Bus Fleets: The Current International Experience."IANGV *Aneedistribution pipceli. e for other users of NG Review Paper. available at . * A proper- regulatorY fiaoinerork to create a fair and 6. IFrailey. Mike, Paul Norton, Nigel N. Clark and Donald level playing field for alL stakeholders should be W. Lyons. 2000. "An Evaluation of Natural Gas versus established by the government. Diesel in Medium-Duty Buses," SAE Technical Paper * Adequiate safter' and performinanice standards that Series 2000-01-2822, Warrendale, Pennsylvania. are monitored and enforced should be in place. This 7. 2001. "Interim report: Emissions Results from need has been underscored by recent cases of CNG Clean Diesel Demonstration Program with CRT FM vehicle fires in Delhi. Particulate Filter at New York City Transit," available at . natural gacs over tbe ]itel it is intended to replace should be adopted. so that the retail price of natural 8. Francchia, Juan Carlos. 2000. "An Overview of the -as is about half that of the liquid fuel. This makes Argentine NGV Experience." presentation made at NG substitution of diesel difficult because the tax on the Workshop on Compressed Natural Gas, 2-3 March, diesel is low in all South Asian countries. The Washington DC. alternative of mandating CNG in the face of 9. Harris.Garth.2000. "CompressedNatural GasinNew unfavorable economics is unlikely to lead to a Zealand," presentation made at the Workshop on sustainable NGV program. Compressed Natural Gas, 2-3 March, Washingtoni DC. This briefing note was prepared in October 2001 as part of the South Asia program on urban air quality management, funded in part by the joint UNDP/World Bank Energy Sector Management Assistance Programme (ESMAP). The objective of the program is to support the region-wide process of developing and adopting cost-effective and realistic policies and efficient enforcement mechanisms to reverse the deteriorating trend in urban air quality. For further information, contact Sameer Akbar (sakbar@worldbank.org) or Masami Kojima (mkojima@worldbank.org). More detailed information on this topic is available in A,, o.hli L. Clean.' Considering the Switch to Natural Gas Buses. World Bank Technical Paper No. 516.