Biomethane CNG hybrid: A reduction by more than 80% of the greenhouse gases emissions compared to gasoline

Comparison of CNG and Gasoline Vehicle Exhaust Emissions: Mass and Composition - The Auto/Oil Air Quality Improvement Research Program

Fuel Management and Exhaust Emissions of Light- and Heavy-Duty Trucks Operating on CNG and LPG

<div class="htmlview paragraph">Understanding source contributions to ambient atmospheric particulate matter (PM) and toxic chemical pollution is critical to the development of effective mobile source emission control strategies. In this part of a larger PM source apportionment study, motor vehicle exhaust was characterized for eighteen light-duty vehicles driven over four driving cycles on a chassis dynamometer. Vehicle emission testing was conducted from July 2005 to May 2006 and included eleven gasoline vehicles, one gasoline-electric hybrid, two compressed natural gas (CNG) vehicles, and four diesel vehicles. Primary gaseous emissions of total hydrocarbons (THC), CO, NO<sub>x</sub>, CO<sub>2</sub>, as well as PM<sub>2.5</sub> (PM with aerodynamic diameter less than 2.5 microns), PM<sub>2.5</sub> elemental and organic carbon (EC/OC), polycyclic aromatic hydrocarbons (PAHs), and potential molecular markers, such as hopanes and steranes, were measured. Presented here are comparisons of regulated emissions, CO<sub>2,</sub> and PM<sub>2.5</sub> EC/OC from gasoline, CNG, and diesel vehicles. Detailed molecular level analysis of PAHs and marker compounds will be presented elsewhere.</div>

The fuel economy of gasoline vehicles will increase to meet 2025 corporate average fuel economy standards (CAFE). However, dedicated compressed natural gas (CNG) and battery electric vehicles (BEV) already exceed future CAFE fuel economy targets because only 15% of non-petroleum energy use is accounted for when determining compliance. This study aims to inform stakeholders about the potential impact of CAFE on life cycle greenhouse gas (GHG) emissions, should non-petroleum fuel vehicles displace increasingly fuel efficient petroleum vehicles. The well-to-wheel GHG emissions of a set of hypothetical model year 2025 light-duty vehicles are estimated. A reference gasoline vehicle is designed to meet the 2025 fuel economy target within CAFE, and is compared to a set of dedicated CNG vehicles and BEVs with different fuel economy ratings, but all vehicles meet or exceed the fuel economy target due to the policy’s dedicated non-petroleum fuel vehicle incentives. Ownership costs and BEV driving ranges are estimated to provide context, as these can influence automaker and consumer decisions. The results show that CNG vehicles that have lower ownership costs than gasoline vehicles and BEVs with long distance driving ranges can exceed the 2025 CAFE fuel economy target. However, this could lead to lower efficiency CNG vehicles and heavier BEVs that have higher well-to-wheel GHG emissions than gasoline vehicles on a per km basis, even if the non-petroleum energy source is less carbon intensive on an energy equivalent basis. These changes could influence the effectiveness of low carbon fuel standards and are not precluded by the light-duty vehicle GHG emissions standards, which regulate tailpipe but not fuel production emissions.

Comparison of the emission factors of air pollutants from gasoline, CNG, LPG and diesel fueled vehicles at idle speed

T recent shale gas revolution has increased the supply of ethane to an unprecedented level. The unexpected surplus of ethane has led to exceedingly low prices and a waste of a resource. Currently, the principal use for ethane is ethylene production. The surplus of ethane is turning into an excess of ethylene. The recent collapse of oil prices has greatly lowered the costs of petroleum-based ethylene, and limits the demand for ethane from ethylene producers. A small proportion of ethane may be blended into natural gas, but the heat value specifications limit the amount of ethane allowed. An increasing amount of ethane will likely be flared, which is a controlled burning of the gas only to get rid of it. Some projections suggest that U.S. ethane production may outgrow demand by hundreds of thousands barrels per day in the coming years. Due to the lack of infrastructure to utilize ethane, it is considered a nuisance in shale gas development. The physical and chemical properties of ethane make it a good a transportation fuel. For the same volume, ethane carries slightly more energy than liquefied natural gas (LNG), but is free from the evaporation loss problem in cryogenic LNG systems. The infrastructure required for ethane transportation are similar to those for compressed natural gas (CNG) vehicles, where the same cylinder can carry more than twice amount of energy in ethane than in CNG. A typical welding cylinder designed for CNG with 16.5 MPa pressure rating can hold liquid ethane safely. Even in hot summer days, when the liquid ethane completely evaporates, the pressure will not rise above the pressure rating. The promotion of natural gas vehicles (NGVs) is faced with several challenges. The CNG vehicles have significantly shorter driving ranges per refill than their gasoline or diesel counterparts. The LNG vehicles have similar driving ranges to the conventional vehicles, but require expensive cryogenic supply chain. Ethane vehicles offer longer driving range than LNG vehicles without cryogenic systems. Utilizing ethane to replace natural gas in transportation could potentially lower the market barriers to a clean alternative fuel and accelerate the adoption of gas vehicles in the United States. The end-use carbon intensity of ethane fuel is slightly higher than natural gas, but significantly lower than gasoline and diesel. We were unable to locate any assessments on upstream emissions for ethane. However, because ethane is a byproduct in natural gas production, its upstream emissions should be similar to that of natural gas. Figure 1 shows the well-to-wheel

Real-world NOx emissions from heavy-duty diesel, natural gas, and diesel hybrid electric vehicles of different vocations on California roadways

Today both the economic growth and expansion of urbanization have increased community access to private cars. Thus, the urban transportation has become a critical part of energy consumption and greenhouse gas emissions. The excessive dependence of urban transportation on high-emission fuels is the main obstacle to develop a low-carbon transport. Meanwhile, natural gas is a bridge fuel to develop a low-emission transport. To the best of our knowledge, there has been little attention towards the association between the development of natural gas-fueled vehicles and the CO2 emission. Therefore, the problem we studied is the role of compressed natural gas (CNG) vehicles in replacing high-emission fuels. In this study, we aimed to study this association by selecting the system dynamics approach due to the complexities of the social-economic system of transportation. In this modeling, different subsystems of the transport fleet were employed including CNG vehicles and urban transportation subsystems. Iran has used CNG as an alternative fuel in the transportation sector, making it one of the three leading countries in the use of natural gas in the urban transportation system. Our case study is focused on Tehran, which is the capital and the largest city of Iran. In this paper, we considered several scenarios to replace the gasoline fuel in the private car sector and taxis and diesel fuel in the bus fleet with natural CNG fuel. The results show that the replacement of CNG fuel with high-emission fuels can have a significant effect on reducing CO2 emissions. In the synthetic scenario, CO2 emission will be decreased by 11.42% in 2030, as compared to the business as usual (BAU) scenario in this year. According to Iran’s commitment to the Paris Agreement, the emission of CO2 in Iran should normally be reduced by 4% in 2030, as compared to its amount in the BAU scenario. Therefore, Iran can easily fulfill its obligations in the urban transport sector only by replacing gasoline and diesel fuel with CNG.

We examine the life cycles of gasoline, diesel, compressed natural gas (CNG), and ethanol (C2H5OH)-fueled internal combustion engine (ICE) automobiles. Port and direct injection and spark and compression ignition engines are examined. We investigate diesel fuel from both petroleum and biosources as well as C2H5OH from corn, herbaceous bio-mass, and woody biomass. The baseline vehicle is a gasoline-fueled 1998 Ford Taurus. We optimize the other fuel/powertrain combinations for each specific fuel as a part of making the vehicles comparable to the baseline in terms of range, emissions level, and vehicle lifetime. Life-cycle calculations are done using the economic input-output life-cycle analysis (EIO-LCA) software; fuel cycles and vehicle end-of-life stages are based on published model results. We find that recent advances in gasoline vehicles, the low petroleum price, and the extensive gasoline infrastructure make it difficult for any alternative fuel to become commercially viable. The most attractive alternative fuel is compressed natural gas because it is less expensive than gasoline, has lower regulated pollutant and toxics emissions, produces less greenhouse gas (GHG) emissions, and is available in North America in large quantities. However, the bulk and weight of gas storage cylinders required for the vehicle to attain a range comparable to that of gasoline vehicles necessitates a redesign of the engine and chassis. Additional natural gas transportation and distribution infrastructure is required for large-scale use of natural gas for transportation. Diesel engines are extremely attractive in terms of energy efficiency, but expert judgment is divided on whether these engines will be able to meet strict emissions standards, even with reformulated fuel. The attractiveness of direct injection engines depends on their being able to meet strict emissions standards without losing their greater efficiency. Biofuels offer lower GHG emissions, are sustainable, and reduce the demand for imported fuels. Fuels from food sources, such as biodiesel from soybeans and C2H5OH from corn, can be attractive only if the co-products are in high demand and if the fuel production does not diminish the food supply. C2H5OH from herbaceous or woody biomass could replace the gasoline burned in the light-duty fleet while supplying electricity as a co-product. While it costs more than gasoline, bioethanol would be attractive if the price of gasoline doubled, if significant reductions in GHG emissions were required, or if fuel economy regulations for gasoline vehicles were tightened.

- Systematic safety research by Korea Government has been made to enhance the safety of CNG (compressed natural gas) vehicles since the burst of compressed cylinder of an urban bus in August 9, 2010. This article summarizes some major activities to ensure the safety of CNG vehicles, which covers review of regulation, safety management system including standard of inspection and certification, and training program of inspectors and car mechanics. Specifically, the followings were reviewed; type of CNG cylinder, location of CNG cylinder, material and type of fuel line and vent line, modification of pipeline connection, installation of gas detector, installation of emergency shutdown valve, installation of protecting cover for cylinder, obligations for CNG vehicle filling station. improving periodical inspection, routine test on gas vehicles, training program for engaged in gas vehicles, and designation of safety manager for CNG bus company. This paper suggests how to improve safety of CNG vehicles as a result of review of above mentioned check items.Key words : CNG vehicles, safety improvement, regulation, safety management

Despite various benefits that the natural gas mobility can provide, CNG (hereinafter – compressed natural gas) and LNG (hereinafter – liquified natural gas) filling infrastructure both in Latvia and the Baltic States as a whole is still at the stage of active development. As a result, the natural gas fuelled vehicle fleet comprises less than 1 % of all registered road vehicles in the Baltics, but, with regards to transport and climate policies of the European Union (hereinafter – the EU), it has a significant potential for further growth. In order to estimate the perspectives of mobility of natural gas, including bioCNG and liquified biomethane (hereinafter – LBM), CNG has been chosen and analysed as a possible alternative fuel in Latvia with its environmental and economic benefits and payback distance for CNG vehicles compared to petrol and diesel cars. The review of various types of CNG filling stations is also presented, along with information on operating tax rates and currently registered vehicles divided by types of fuel in Latvia. It was established that with the Latvian fuel price reference of the late 2020, exploitation of CNG-powered vehicle was by 24 % cheaper per kilometre in comparison with diesel and by 66 % cheaper in comparison with petrol vehicles. CNG vehicles have smaller operational taxes, since they are based on carbon dioxide (hereinafter – CO) emissions, which are lower for CNG-powered vehicles. Calculation results also indicate that CNG vehicle payback time may fall within the warrant period, if at least 57650 kilometres as an alternative to a petrol vehicle or 71 531 kilometres as an alternative to a diesel vehicle are driven by it.

To reduce the primary emissions of traffic and therefore the harm caused to humans and the environment, alternative fuels, for example Compressed Natural Gas (CNG), have been developed. However, the amount of secondary particles, that are formed in the atmosphere from gaseous precursors such as Volatile Organic Compounds (VOC), can even exceed primary particle emissions. Their emissions and formation mechanisms remain poorly understood.As a part of a larger project, the primary and secondary emissions of seven passenger cars were measured. In this study, three cars are compared: a Euro 6d-TEMP CNG (model year 2020, gasoline as a backup fuel), a Euro 6b gasoline (2015) and a Euro 4 diesel (2006) vehicle. All the vehicles had an oxidation catalyst, but no particulate filter. The measurements were done on a chassis dynamometer, which was in a temperature-controlled test cell with test temperatures of -9, 23, and 35 ˚C. The test cycle simulated Real Driving Emissions (RDE) and was 72 min and 47 km long.The raw exhaust was diluted with a porous tube diluter (PTD) and an ejector diluter (ED), and then characterized physically and chemically. For example, the VOC spectra of the fresh exhaust was measured with a Proton Transfer Reaction Time of Flight mass spectrometer PTR-ToF-CIMS (VOCUS, Aerodyne Research, US). This instrument allows high time and mass resolution analysis of the spectra.Based on the preliminary results, the VOC composition in the CNG and the diesel car exhaust was similar, with emphasis on oxygenated VOCs. In contrast, the gasoline car emitted more aromatic, polyaromatic and aliphatic hydrocarbons. The VOC concentrations from the CNG car were on average lower than from the diesel car, but the CNG car emitted higher concentrations at cold start and at highway. The VOC concentrations from the gasoline vehicle were also highest at cold start and at highway during the cycle.In summary, the CNG vehicle seems to emit low VOC concentrations, and the emitted compounds have low secondary aerosol formation potential. However, at cold start and during high engine load, the concentrations increase greatly, potentially due to gasoline usage. This study provided new information about the VOC composition in a CNG car exhaust and supported previous studies in terms of diesel and gasoline cars. ACKNOWLEDGEMENTS: This work was supported by the European Union’s Horizon Europe research and innovation programme under grant agreement No 101096133 (PAREMPI: Particle emission prevention and impact: from real world emissions of traffic to secondary PM of urban air).

Consumers and organizations worldwide are searching for low-carbon alternatives to conventional gasoline and diesel vehicles to reduce greenhouse gas (GHG) emissions and their impact on the environment. A comprehensive technique used to estimate overall cost and environmental impact of vehicles is known as life cycle assessment (LCA). In this article, a comparative LCA of diesel and compressed natural gas (CNG) powered heavy duty refuse collection vehicles (RCVs) is conducted. The analysis utilizes real-time operational data obtained from the City of Surrey in British Columbia, Canada. The impact of the two alternative vehicles is assessed from various points in their life. No net gain in energy use is found when a diesel powered RCV is replaced by a CNG powered RCV. However, significant reductions (about 24 % CO2-equivalent) in GHG emissions are obtained. Moreover, fuel cost estimations based on 2011 price levels and a 5 year lifetime for both RCVs reveal that considerable cost savings may be achieved by switching to CNG vehicles. Thus, CNG RCVs are not only favorable in terms of reduced climate change impact but also cost effective compared to conventional diesel RCVs, and provide a viable and realistic near-term strategy for cities and municipalities to reduce GHG emissions.

Compressed Natural Gas (CNG) is a clean substitute fuel for vehicle with broad application prospect, due to its enormous advantage in resource, environment and economy. This paper investigated development of CNG vehicle in Shanghai. Main factors constraining CNG vehicle application in Shanghai were scarcity of gas resource and gas station, declining in power performance and higher original investment CNG vehicle in Shanghai has broad prospect. CNG vehicle showed remarkable economic benefit. Calculation showed obvious reduction in fuel cost, 77.71 million RMB and 158.35 million RMB per year with 50% and 100% fuel replacing by CNG for public bus in Shanghai, while 129.42 million and 258.71 million RMB with 50% and 100% fuel replacing for taxi. Sufficient gas resource supply will be guaranteed, estimating 10 billion m3 totally in 2011. Positive policies are initiated by the government. Development of related technologies strongly supports its application. However, further improvements on CNG engine, gas station and government policy are essential.

Greenhouse gas emissions from heavy-duty vehicles