Our findings translate into several policy considerations:

• Prioritize immediate adoption of BEVs, while accounting for regional gridmix variations-delaying BEV uptake risks locking in long-term emissions from ICEs as India’s grid gradually decarbonizes.
• Enforce stringent fuel efficiency standards and give importance to real-world adjustment factors to close the lab-to-road gap, ensuring accurate life cycle emissions accounting and promoting truly energy-efficient vehicles. HEVs exhibit higher deviations from test-cycle performance than ICE, while BEVs consistently demonstrate the highest energy efficiency across all powertrains.
• Requiring on-board fuel and energy consumption meters to collect real-world data across all powertrains can help to refine future life-cycle assessments and inform evidence-based policy design.
• Incorporate land-use change impacts in biofuel life cycle assessments, as statistical analysis highlights that biofuel-related emissions are often significantly underestimated in existing studies.

The post Review of greenhouse gas life-cycle assessments of passenger cars in India appeared first on International Council on Clean Transportation.

• Business-as-Usual, with a base year of 2019, prior to LEZ implementation;
• LEZ, according to the original LEZ schedule adopted in 2018; and
• LEZ + Good Move, again assuming the original LEZ schedule with policies that incorporate modal shift and traffic reduction strategies.

The analysis projects that the Brussels LEZ, if implemented under the original schedule adopted in 2018, nearly doubles the annual life-cycle GHG reductions by 2030 compared with the Business-as-Usual scenario, or roughly 45% compared to 2019 levels. Between 2019 and 2040, the LEZ is projected to avoid 3.9 Mt of GHG emissions, equivalent to the GHG emissions from around 83,000 gasoline cars.

Under the LEZ + Good Move scenario, the reduction rate of GHG emissions grows. By 2040, 5.7 Mt of GHG emissions are projected to be avoided compared with the Business-as-Usual scenario, which is equivalent to the emissions of around 121,000 gasoline cars.

The paper also models the potential effect of additional policies aimed at strengthening the impact of the LEZ on life-cycle GHG emission reductions. It also analyses the potential impact of future implementation delays.

The study shows that the LEZ in the BCR remains an effective tool for substantially reducing life-cycle GHG emissions from on-road vehicles and underscores its potential to expedite the transition toward less-polluting, or zero-emission, transportation to help meet the city’s air quality and climate goals.

Figure. Annual life-cycle GHG emissions of the Brussels LEZ with a base year of 2019 for each scenario

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The post Fuel-cycle greenhouse gas emissions from a 40-tonne tractor-trailer for diesel and compressed natural gas (CNG) appeared first on International Council on Clean Transportation.

A recent report by the North American Council for Freight Efficiency (NACFE) highlighted the role of natural gas as a transport fuel and estimated that the greenhouse gas (GHG) emission savings from a natural gas engine are in the range of 13%–18% compared with diesel fuel. However, NACFE “focused most [its] discussion on the tank-to-wheels effects of the alternate fuels” in comparing a natural gas-powered truck with a diesel truck doing the same route. An analysis of the complete fuel-cycle GHG emissions (i.e., well-to-wheel) would cover emissions associated with all the steps of producing, transporting, and consuming the natural gas and diesel used for those trucks. As I’ll show here, the emission impacts of the upstream natural gas supply chain complicate the climate benefits of using natural gas for trucks.

The primary issue is methane leakage. Natural gas is mostly methane (85%–90% by volume) and its production involves multiple steps during which methane could be released into the atmosphere through leaks and venting. This happens all along the supply chain and these upstream emissions are noteworthy because methane is a potent GHG.

Upstream methane emissions can be substantial and they’re not easy to estimate. For example, using ground-based measurements validated by aircraft observations, researchers have estimated that methane emissions from the oil and natural gas (O&NG) industry are much higher than previously estimated by the U.S. Environmental Protection Agency (EPA). Methane emission estimates reported in EPA’s national GHG inventory are based on adding up the emissions from individual components of natural gas production equipment. Although this kind of bottom-up methodology provides detailed data from routine equipment behavior, it does not detect super-emitters, which can be unpredictable and can emit unusually large amounts of methane (one example is malfunctioning equipment). Alternate measurement approaches such as remote sensing of methane emissions via satellites or aerial surveys can help cover vast areas and detect these super-emitters, but such top-down emission estimates can also overestimate emissions. For instance, this technique might not be able to differentiate between O&NG sites and other sources of methane, such as landfills or dairy farms.

It’s also important to differentiate between emissions from combined O&NG production and emissions from producing just natural gas. For sites that produce both fuels, part of the methane emissions should be attributed to the oil produced alongside natural gas on an energy-weighted basis. The left column in Figure 1 illustrates the range of methane losses from O&NG production normalized by natural gas production using data from recent literature. These losses are calculated by dividing methane emissions by the amount of methane produced. The data from both bottom-up (e.g., EPA) and hybrid methodologies (i.e., a mix of bottom-up data and satellite or aerial surveys) were used for these estimates. The methane loss estimates in the right column in Figure 1 illustrate the emissions allocated solely to natural gas production, so they are allocation-adjusted loss rates. When the O&NG sector is considered, the methane loss rate ranges between 0.4% and 9.6%, with a mean of 3.4%. When losses are allocation adjusted, it ranges between 0.4% and 4.8%, with 1.8% as the mean.

Figure 1. Methane emissions from oil and natural gas (O&NG) production and emissions allocated to natural gas (NG) production from recent literature

Note: Methane emissions from O&NG production are from Alvarez et al. (2018), EPA (2024), and Sherwin et al. (2024). Methane emissions allocated to NG production are from Omara (2018) and Sherwin et al. (2024). 

To understand the climate impacts of upstream methane losses, let’s explore the fuel cycle GHG emissions of natural gas-powered heavy-duty trucks. Figure 2 illustrates the differences in well-to-wheel GHG emissions for 40-tonne trucks that run on compressed natural gas (CNG), normalized per mile, for each fuel option analyzed. We used the mean methane loss rate for natural gas production (1.8%) as well as the minimum (0.4%) and maximum (4.8%) loss rates from Figure 1 to provide the range of emissions estimates indicated by the error bar. The fuel economy of a heavy truck running on natural gas of 6.5 miles per diesel gallon equivalent was taken from the NACFE report. To compare our analysis with diesel-powered trucks, we used the U.S. national average for the carbon intensity of diesel fuel from the U.S. Renewable Fuel Standard, 91.9 g CO₂e/MJ. Non-CO₂ tailpipe emissions (methane and nitrous oxide) from GREET 2023 were included as equivalent amounts of CO₂ in the combustion emissions for diesel and natural gas-powered trucks. The system boundary for natural gas includes extraction, processing, transport, fuel refining and distribution, and methane leakage for all steps. As illustrated in Figure 2, with the mean methane emissions rate of 1.8%, our estimates are a 6% GHG emission savings from CNG trucks compared with diesel ones. However, the same estimate shows that if there is a methane leakage rate greater than 2.5%, that would make CNG trucks worse than diesel ones from a climate perspective.

Figure 2. Fuel-cycle greenhouse gas emissions from a 40-tonne tractor-trailer for diesel and compressed natural gas (CNG)

Note: Fossil CNG results are estimated using GREET 2023 and assumptions therein for CNG production and combustion in dedicated CNG-fueled vehicles using a 100-year global warming potential for greenhouse gases. 

Thus, even with optimistic assumptions for upstream methane leakage, we estimate that CNG trucks only offer mild GHG reductions, if any, compared with petroleum diesel. This means that the estimated GHG savings for switching to natural gas trucks are marginal at best. However, there is also a long-term problem: Purchasing natural gas trucks may create technology lock-in. The CNG trucks purchased today and in the next several years could be on the road well into the 2030s, when zero-emission vehicles that provide much larger emission benefits could be more widely available. Battery electric trucks using grid-average electricity already generate deeper GHG savings than CNG trucks in many regions, and these GHG savings will grow over time as the grid decarbonizes. Adopting CNG could mean foregoing substantial GHG savings in the future from zero-emission vehicles.

Author

Gonca Seber Olcay
Researcher

Related Publications

A comparison of the life-cycle greenhouse gas emissions of European heavy-duty vehicles and fuels

This study is a life-cycle comparison of the greenhouse gas emissions from combustion, electric, and hydrogen trucks and buses in Europe. The analysis evaluates the lifetime emissions of different powertrains on a fully harmonized basis, comparing both the emissions attributable to fuel production and consumption as well as the emissions attributable to the vehicle’s manufacturing.

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Decarbonizing TransportLife-cycle analyses

SectorFuels

PoliciesGHG emissions

RegionUnited StatesUnited States & Canada

The post How upstream methane leakage further weakens the argument for natural gas trucks appeared first on International Council on Clean Transportation.

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This analysis developed criteria and ranked the strengths and weaknesses of state policies related to three overall goals: long-term decarbonization, sustainability, and equity. As seen in the illustration below, current and proposed SAF polices generally lack provisions to ensure that these goals are all fully met.

Recommendations for improving state SAF policies include the following principles:

• Prioritize low-carbon second-generation pathways for producing SAF.
• Develop policies that provide certainty to investors over longer time frames.
• Establish binding policies to disincentivize the use of fossil jet fuel and drive SAF deployment.

The post SAF policy scorecard: Evaluating state-level sustainable aviation fuel policies in the United States appeared first on International Council on Clean Transportation.

Este estudo analisa o impacto financeiro e ambiental de duas alternativas já disponíveis no mercado brasileiro: caminhões elétricos a bateria e a gás natural veicular (GNV), que podem ser movidos tanto a gás natural fóssil quanto com biometano (o estudo considera o biometano produzido a partir de resíduos de aterros sanitários). O componente financeiro se baseia na estimativa do custo total de propriedade por quilômetro em cada tipo de veículo, enquanto a análise ambiental considera as emissões de gases de efeito estufa no ciclo de vida de cada uma das opções.

Entre os principais resultados:

• Custos totais de propriedade de caminhões coletores elétricos e a GNV são entre 25% e 27% maiores, respectivamente, do que os de um veículo comparável a diesel nas condições atuais.
• Reduções nos custos de financiamento e o aumento no número de anos de operação podem tornar os caminhões elétricos financeiramente competitivos.
• Caminhões elétricos e os operados exclusivamente com biometano produzido de aterros sanitários tem emissões do ciclo de vida de 70% e 68% menores, respectivamente, do que as identificadas nos veículos a diesel.
• Em contrapartida, um caminhão movido exclusivamente a gás natural de origem fóssil emite 23% a mais que os movidos a diesel, devido à menor eficiência do motor e às emissões fugitivas de metano ao longo do ciclo de vida do combustível.

O estudo apresenta ainda recomendações, ancoradas nos resultados identificados, para garantir a redução das emissões da frota de coleta de São Paulo nos próximos anos.

The post Descarbonização da frota de coleta de resíduos sólidos em São Paulo appeared first on International Council on Clean Transportation.

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La plataforma E-Bus Radar (www.ebusradar.org) acompaña la implementación de autobuses eléctricos a batería (BEBs) y trolebuses en los sistemas de transporte público de las ciudades latinoamericanas, y sus reducciones asociadas en las emisiones de gases de efecto invernadero en comparación con los modelos convencionales. La plataforma fue creada y es mantenida por la asociación Zero Emission Bus Rapid-deployment Accelerator (ZEBRA), co-liderada por el Consejo Internacional de Transporte Limpio (ICCT) y la organización C40 Cities.

Este trabajo presenta la nueva metodología de cálculos de la plataforma E-Bus Radar, con el desarrollo de una evaluación del ciclo de vida (ECV) para estimar las emisiones de gases de efecto invernadero evitadas con la introducción de autobuses eléctricos a batería y trolebuses. Con esta actualización, los resultados obtenidos contabilizan las emisiones de escape y las emisiones asociadas a la fabricación del vehículo y de la batería, al mantenimiento del vehículo y a la producción de combustible y electricidad, teniendo en cuenta valores específicos de los países de América Latina.

Los autobuses se clasifican en cinco categorías: trolebuses de 12 a 15 m, trolebuses de más de 18 m, BEBs de 8 a 11 m, BEBs de 12 a 15 m y BEBs de más de 18 m. Para cada categoría y ciudad, las emisiones calculadas se estiman en base a la información técnica y operativa proporcionada por las autoridades de transporte público y los fabricantes.

El financiamiento para este trabajo fue generosamente proporcionado por el Instituto Clima y Sociedad (iCS).

The post Cuantificación de las emisiones de gases de efecto invernadero evitadas por autobuses eléctricos en Latinoamérica: metodología simplificada de análisis de ciclo de vida appeared first on International Council on Clean Transportation.

Leia este estudo em espanhol ou inglês.

A plataforma E-Bus Radar (www.ebusradar.org) acompanha a implementação de ônibus elétricos a bateria e trolébus nos sistemas de transporte público das cidades latino-americanas, e suas reduções associadas nas emissões de gases de efeito estufa em comparação aos modelos convencionais. A plataforma foi criada e é mantida pela parceria Zero Emission Bus Rapid-deployment Accelerator (ZEBRA), co-liderada pelo Conselho Internacional de Transporte Limpo (ICCT) e a organização C40 Cities.

Este trabalho apresenta a nova metodologia de cálculos da plataforma E-Bus Radar, com o desenvolvimento de uma avaliação do ciclo de vida (ACV) para estimar as emissões de gases de efeito estufa evitadas com a introdução de ônibus elétricos a bateria (BEBs) e trólebus. Com esta atualização, os resultados obtidos contabilizam as emissões de escapamento e as emissões associadas à fabricação do veículo e da bateria, à manutenção do veículo e à produção de combustível e eletricidade, levando em consideração valores específicos de países na América Latina.

Os ônibus são classificados em cinco categorias: trólebus de 12 a 15 m, trólebus acima de 18 m, BEBs de 8 a 11 m, BEBs de 12 a 15 m e BEBs acima de 18 m. Para cada categoria e cidade, as emissões calculadas são estimadas com base em informações técnicas e operacionais fornecidas pelas autoridades de transporte público e pelos fabricantes.

O financiamento para este trabalho foi generosamente fornecido pelo Instituto Clima e Sociedade (iCS).

The post Quantificação das emissões de gases de efeito estufa evitadas por ônibus elétricos na América Latina: uma metodologia simplificada de avaliação do ciclo de vida appeared first on International Council on Clean Transportation.

The E-Bus Radar platform (www.ebusradar.org) monitors the implementation of battery electric buses (BEBs) and trolleybuses in the public transport systems of Latin American cities, and their associated reductions in greenhouse gas emissions compared to conventional models. The platform was created and is maintained by the Zero Emission Bus Rapid-deployment Accelerator (ZEBRA) partnership, co-led by the International Council on Clean Transportation (ICCT) and C40 Cities.

This work presents the updated methodology used by the E-Bus Radar platform to estimate greenhouse gas emissions avoided with the introduction of battery electric buses and trolleybuses. With this update, which includes the application of a life-cycle assessment, the results obtained account for exhaust emissions and emissions associated with vehicle and battery manufacturing, vehicle maintenance, and fuel and electricity production. The methodology uses country-specific values to provide reliable life-cycle emission estimates tailored to the local market.

The buses are classified into five categories: trolleybuses from 12 to 15 m, trolleybuses over 18 m, BEBs from 8 to 11 m, BEBs from 12 to 15 m, and BEBs over 18 m. For each category and city, the calculated emissions are estimated based on technical and operational information provided by public transport authorities and manufacturers.

The funding for this work was generously provided by the Instituto Clima e Sociedade (iCS).

Read this paper in Spanish or Portuguese.

The post Quantifying avoided greenhouse gas emissions by E-Buses in Latin America: a simplified life-cycle assessment methodology appeared first on International Council on Clean Transportation.