Abating transport GHG emissions by hydrogen fuel cell vehicles: Chances for the developing world

Fuel cell vehicles, as the most promising clean vehicle technology for the future, represent the major chances for the developing world to avoid high-carbon lock-in in the transportation sector. In this paper, by taking China as an example, the unique advantages for China to deploy fuel cell vehicles are reviewed. Subsequently, this paper analyzes the greenhouse gas (GHG) emissions from 19 fuel cell vehicle utilization pathways by using the life cycle assessment approach. The results show that with the current grid mix in China, hydrogen from water electrolysis has the highest GHG emissions, at 3.10 kgCO₂/km, while by-product hydrogen from the chlor-alkali industry has the lowest level, at 0.08 kgCO₂/km. Regarding hydrogen storage and transportation, a combination of gas-hydrogen road transportation and single compression in the refueling station has the lowest GHG emissions. Regarding vehicle operation, GHG emissions from indirect methanol fuel cell are proved to be lower than those from direct hydrogen fuel cells. It is recommended that although fuel cell vehicles are promising for the developing world in reducing GHG emissions, the vehicle technology and hydrogen production issues should be well addressed to ensure the life-cycle low-carbon performance.     

Hydrogen vehicles: Impacts of DOE technical targets on market acceptance and societal benefits

Hydrogen vehicles (H₂V), including H₂ internal combustion engine, fuel cell and fuel cell plug-in hybrid, could greatly reduce petroleum consumption and greenhouse gas (GHG) emissions in the transportation sector. The U.S. Department of Energy has adopted targets for vehicle component technologies to address key technical barriers to widespread commercialization of H₂Vs. This study estimates the market acceptance of H₂Vs and the resulting societal benefits and subsidy in 41 scenarios that reflect a wide range of progress in meeting these technical targets. Important results include: (1) H₂Vs could reach 20–70% market shares by 2050, depending on progress in achieving the technical targets. With a basic hydrogen infrastructure (∼5% hydrogen availability), the H₂V market share is estimated to be 2–8%. Fuel cell and hydrogen costs are the most important factors affecting the long-term market shares of H₂Vs. (2) Meeting all technical targets on time could result in about an 80% cut in petroleum use and a 62% (or 72% with aggressive electricity de-carbonization) reduction in GHG in 2050. (3) The required hydrogen infrastructure subsidy is estimated to range from $22 to $47 billion and the vehicle subsidy from $4 to $17 billion. (4) Long-term H₂V market shares, societal benefits and hydrogen subsidies appear to be highly robust against delay in one target, if all other targets are met on time. R&D diversification could provide insurance for greater societal benefits. (5) Both H₂Vs and plug-in electric vehicles could exceed 50% market shares by 2050, if all targets are met on time. The overlapping technology, the fuel cell plug-in hybrid electric vehicle, appears attractive both in the short and long runs, but for different reasons.     

Flexible sector coupling with hydrogen: A climate-friendly fuel supply for road transport

The substantial expansion of renewable energy sources is creating the foundation to successfully transform the German energy sector (the so-called ‘Energiewende’). A by-product of this development is the corresponding capacity demand for the transportation, distribution and storage of energy. Hydrogen produced by electrolysis offers a promising solution to these challenges, although the willingness to invest in hydrogen technologies requires the identification of competitive and climate-friendly pathways in the long run. Therefore, this paper employs a pathway analysis to investigate the use of renewable hydrogen in the German passenger car transportation sector in terms of varying market penetration scenarios for fuel cell-electric vehicles (FCEVs). The investigation focuses on how an H₂ infrastructure can be designed on a national scale with various supply chain networks to establish robust pathways and important technologies, which has not yet been done. Therefore, the study includes all related aspects, from hydrogen production to fueling stations, for a given FCEV market penetration scenario, as well as the CO₂ reduction potential that can be achieved for the transport sector. A total of four scenarios are considered, estimating an FCEV market share of 1–75% by the year 2050. This corresponds to an annual production of 0.02–2.88 million tons of hydrogen. The findings show that the most cost-efficient H₂ supply (well-to-tank: 6.7–7.5 €/kg_H2) can be achieved in high demand scenarios (FCEV market shares of 30% and 75%) through a combination of cavern storage and pipeline transport. For low-demand scenarios, however, technology pathways involving LH₂ and LOHC truck transport represent the most cost-efficient options (well-to-tank: 8.2–11.4 €/kg_H2).     

Greenhouse gas implications of using coal for transportation: Life cycle assessment of coal-to-liquids,plug-in hybrids,and hydrogen pathways

Using coal to produce transportation fuels could improve the energy security of the United States by replacing some of the demand for imported petroleum. Because of concerns regarding climate change and the high greenhouse gas (GHG) emissions associated with conventional coal use, policies to encourage pathways that utilize coal for transportation should seek to reduce GHGs compared to petroleum fuels. This paper compares the GHG emissions of coal-to-liquid (CTL) fuels to the emissions of plug-in hybrid electric vehicles (PHEV) powered with coal-based electricity, and to the emissions of a fuel cell vehicle (FCV) that uses coal-based hydrogen. A life cycle approach is used to account for fuel cycle and use-phase emissions, as well as vehicle cycle and battery manufacturing emissions. This analysis allows policymakers to better identify benefits or disadvantages of an energy future that includes coal as a transportation fuel. We find that PHEVs could reduce vehicle life cycle GHG emissions by up to about one-half when coal with carbon capture and sequestration is used to generate the electricity used by the vehicles. On the other hand, CTL fuels and coal-based hydrogen would likely lead to significantly increased emissions compared to PHEVs and conventional vehicles using petroleum-based fuels.     

Large-scale long-distance land-based hydrogen transportation systems: A comparative techno-economic and greenhouse gas emission assessment

Interest in hydrogen as an energy carrier is growing as countries look to reduce greenhouse gas (GHG) emissions in hard-to-abate sectors. Previous works have focused on hydrogen production, well-to-wheel analysis of fuel cell vehicles, and vehicle refuelling costs and emissions. These studies use high-level estimates for the hydrogen transportation systems that lack sufficient granularity for techno-economic and GHG emissions analysis. In this work, we assess and compare the unit costs and emission footprints (direct and indirect) of 32 systems for hydrogen transportation. Process-based models were used to examine the transportation of pure hydrogen (hydrogen pipeline and truck transport of gaseous and liquified hydrogen), hydrogen-natural gas blends (pipeline), ammonia (pipeline), and liquid organic hydrogen carriers (pipeline and rail). We used sensitivity and uncertainty analyses to determine the parameters impacting the cost and emission estimates. At 1000 km, the pure hydrogen pipelines have a levelized cost of $0.66/kg H₂ and a GHG footprint of 595 gCO₂eq/kg H₂. At 1000 km, ammonia, liquid organic hydrogen carrier, and truck transport scenarios are more than twice as expensive as pure hydrogen pipeline and hythane, and more than 1.5 times as expensive at 3000 km. The GHG emission footprints of pure hydrogen pipeline transport and ammonia transport are comparable, whereas all other transport systems are more than twice as high. These results may be informative for government agencies developing policies around clean hydrogen internationally.     

Analysis of policies to reduce oil consumption and greenhouse-gas emissions from the US transportation sector

Even as the US debates an economy-wide CO₂ cap-and-trade policy the transportation sector remains a significant oil security and climate change concern. Transportation alone consumes the majority of the US’s imported oil and produces a third of total US Greenhouse-Gas (GHG) emissions. This study examines different sector-specific policy scenarios for reducing GHG emissions and oil consumption in the US transportation sector under economy-wide CO₂ prices. The 2009 version of the Energy Information Administration’s (EIA) National Energy Modeling System (NEMS), a general equilibrium model of US energy markets, enables quantitative estimates of the impact of economy-wide CO₂ prices and various transportation-specific policy options. We analyze fuel taxes, continued increases in fuel economy standards, and purchase tax credits for new vehicle purchases, as well as the impacts of combining these policies. All policy scenarios modeled fail to meet the Obama administration’s goal of reducing GHG emissions 14% below 2005 levels by 2020. Purchase tax credits are expensive and ineffective at reducing emissions, while the largest reductions in GHG emissions result from increasing the cost of driving, thereby damping growth in vehicle miles traveled.     

Evaluation of the feasibility of ethanol and gasoline in solid oxide fuel cell vehicles in Brazil

The transport sector is one of the main sources of greenhouse gas emissions and nowadays there are many alternatives to reduce emissions from light-duty vehicles. Currently, plug-in electric vehicles are the main alternative to reduce emissions from cars; however, this technology has some disadvantages, such as the demand for infrastructure. Another car propulsion technology to reduce emissions is the Solid Oxide Fuel Cell. This technology offers interesting advantages especially for countries that produce bioethanol, for example, the possibility to use the current fuel infrastructure. Therefore, the Solid Oxide Fuel Cell is a promising technology to reduce carbon emissions in Brazil. This study compared ethanol and gasoline to identify what fuel is more interesting to be used in FCEVs in Brazil. The results indicated that ethanol has more economic, environmental, and social advantages than gasoline.     

Spatial and temporal optimization of hydrogen fuel supply chain for light duty passenger vehicles in British Columbia

British Columbia is well positioned to capitalize on its natural resources and its carbon policies towards the development of a hydrogen fueling network. A multi-period optimization model was developed to design a hydrogen fuel supply chain based on a mixed integer linear programming formulation. The model was applied to the light duty passenger vehicle sector in British Columbia under three hydrogen demand scenarios. As part of the objective function, the model incorporated the current provincial emissions mitigation policies, i.e., a carbon tax and a low-carbon fuel standard (LCFS). Based on cost, our model indicates that steam methane reforming (SMR) is the least costly hydrogen production technology even with carbon policies in place. However, SMR would result in higher emissions (compared to other pathways). Coupling the carbon tax with the LCFS can be a suitable policy option when hydrogen price and GHG emissions are weighted equally.     

Blending blue hydrogen with natural gas for direct consumption: Examining the effect of hydrogen concentration on transportation and well-to-combustion greenhouse gas emissions

Jurisdictions are looking into mixing hydrogen into the natural gas (NG) system to reduce greenhouse gas (GHG) emissions. Earlier studies have focused on well-to-wheel analysis of H₂ fuel cell vehicles, using high-level estimates for transportation-based emissions. There is limited research on transportation emissions of hythane, a blend of H₂ and NG used for combustion. An in-depth analysis of the pipeline transportation system was performed for hythane and includes sensitivity and uncertainty analyses. When hythane with 15% H₂ is used, transportation GHG emissions (gCO2eq/GJ) increase by 8%, combustion GHG emissions (gCO2eq/GJ) decrease by 5%, and pipeline energy capacity (GJ/hr) decreases by 11% for 50–100 million m³/d pipelines. Well-to-combustion (WTC) emissions increase by 2.0% without CCS, stay the same with a 41% CCS rate, decrease by 2.8% for the 100% CCS scenario, and decrease by 3.6% in the optimal CO₂-free scenario. While hythane contains 15% H₂ by volume only 5% of the gas’ energy comes from H₂, limiting its GHG benefit.     

Hydrogen utilization in various transportation modes with emissions comparisons for Ontario, Canada

The paper compares the atmospheric emissions of different hydrogen production scenarios for various transportation modes in a case study for Ontario, Canada. Hydrogen demand scenarios are based on historical data of the various transportation modes. Predicting the CO₂ emissions for a market with hydrogen vehicles against a purely fossil fuel market outlines the benefits of utilizing hydrogen. For road vehicles less than 4,500 kg in weight, emissions from a thermochemical production fraction of 20% produced a 9.8% decrease in CO₂ emissions (or over 3,000 kilotonnes), compared to a 100% fossil fuel market. When these studies are applied to other transportation modes such as rail, air and marine, similar trends are observed. The largest benefits occur from automobiles and rail, where increasing carbon emission trends were reversed due to the increasing hydrogen propulsion base. Further decreases in carbon dioxide emissions could be realized by lower emitting production sources such as nuclear thermochemical production and electrolysis from wind, solar, and hydro.     

Methodology for assessing emission reduction of truck-only toll lanes

The emissions of carbon dioxide (CO₂), the largest component of greenhouse gases (GHG) emissions, emitted from heavy trucks is second only to passenger cars in terms of GHG emissions from the transportation sector. Truck-only toll (TOT) lanes have been proposed in several cities as a means of improving truck flows and reducing freeway congestion. This paper describes an analysis that utilized the US EPA's MOBILE6.2 vehicle emissions modeling software to identify freeway locations with large pollutant emissions and estimated the changes in emission associated with TOT lanes. Emissions including hydrocarbon (HC), carbon monoxide (CO), nitrogen oxide (NO_x), and CO₂ were estimated by multiplying vehicle kilometers traveled by emission factors associated with various vehicle types and average speeds. The CO₂ calculation was limited due to lack of sensitivity in the model of speed variation, which is one of the benefits of the implementation of TOT lanes. Mechanical equations of engine horsepower involving the change in vehicle speeds is applied to estimate the change in CO₂ fuel consumption and then converted to estimate the change in CO₂ emissions. The results show that voluntary and mandatory use of TOT lanes would reduce total CO₂ emissions on all freeway lanes by 62% and 60%.     

Comparison of the technical potential for hydrogen,battery electric,and conventional light-duty vehicles to reduce greenhouse gas emissions and petroleum consumption in the United States

Light-duty vehicles (LDV) are responsible for a large fraction of petroleum use and are a significant source of greenhouse gas (GHG) emissions in the United States. Improving conventional gasoline-powered vehicle efficiency can reduce petroleum demand, however efficiency alone cannot reach deep GHG reduction targets, such as 80% below the 1990 LDV GHG emissions level. Because the cost and availability of low-GHG fuels will impose limits on their use, significant reductions in GHG emissions will require combinations of fuel and vehicle technologies that both increase efficiency and reduce the emissions from fuel production and use. This paper examines bounding cases for the adoption of individual technologies and then explores combinations of advanced vehicle and fuel technologies. Limits on domestic biofuel production—even combined with significant conventional combustion engine vehicle improvements—mean that hydrogen fuel cell electric or battery electric vehicles fueled by low-GHG sources will be necessary. Complete electrification of the LDV fleet is not required to achieve significant GHG reduction, as replacing 40% of the LDV fleet with zero-emission hydrogen vehicles while achieving optimistic biofuel production and conventional vehicle improvements can allow attainment of a low GHG emission target. Our results show that the long time scale for vehicle turnover will ensure significant emissions from the LDV sector, even when lower emission vehicles and fuels are widely available within 15 years. Reducing petroleum consumption is comparatively less difficult, and significant savings can be achieved using efficient conventional gasoline-powered vehicles.     

Potential impact of transition to a low-carbon transport system in Iceland

This paper develops a system dynamics model of Iceland׳s energy sector (UniSyD_IS) that is based on the UniSyD_NZ model of New Zealand׳s energy economy. The model focuses on the energy supply sector with endogenous representation of road transport energy demand. Equilibrium interactions are performed across electricity, hydrogen, biofuels, and road transport sectors. Possible transition paths toward a low-carbon transport in Iceland are explored with implications for fuel demand, greenhouse gas (GHG) emissions and associated costs. The consumer sector simulates the long-term evolution of light and heavy-duty vehicles through a vehicle choice algorithm that accounts for social influences and consumer preferences. Through different scenarios, the influences of four fundamental driving factors are examined. The factors are oil price, carbon tax, fuel supply-push, and government incentives. The results show that changes in travel demand, vehicle technologies, fuel types, and efficiency improvements can support feasible transition paths to achieve sufficient reduction in GHG for both 4 °C and 2 °C climate scenarios of the Nordic Energy Technology Perspectives study. Initial investment in supply infrastructure for alternative fuels will not only mitigate GHG emissions, but also could provide long-term economic benefits through fuel cost saving for consumers and reduced fuel import costs for government.     

Willingness to pay for hydrogen fuel cell electric vehicles in China: A choice experiment analysis

The hydrogen energy is considered to be main power source of transport sector in the future, and a huge amount of funds have been invested into developing hydrogen fuel cell electric vehicles (FCEVs). Since FCEVs are in initial development stage and there're few FCEVs on the road, before their expansion this paper intends to conduct an economic analysis for FCEVs by using the choice experiment method. In the choice experiment, 1072 participants were required to select among two FCEVs and one conventional fuel vehicle. Logit models were estimated and then the results were used to calculate the willingness to pay for FCEVs. Results showed that purchase price, driving range, refueling time, fuel cost, emissions reduction, refueling accessibility are significant influences, and the marginal values for every 200 km improvement in driving range, 5 min reduction in refueling time, RMB 0.5/kilometer reduction in fuel cost, 20% reduction in emissions, and 20% improvement of refueling accessibility were estimated to be RMB 49,091, 12,727, 3818, 47,818, and 12,909, respectively. A range of FCEV configurations were calculated, and compared to a gasoline-powered counterpart the extra value that customers were likely to pay for a FCEV ranged from RMB 20,810 to 95,310. These results have significant implications for promoting FCEVs and contribute to better sustainability in transport sector.     

Commercial potential for renewable hydrogen in California

The market for renewable hydrogen in California is based primarily on the projected need for hydrogen fuel for fuel cell electric vehicles (FCEV) as they are currently coming to the roads in California. The demand is projected to be 70 million kg/year by 2030. This analysis shows that hydrogen demand can be filled through commercial electrolysis using excess renewable energy. This paper is also focused on the revenue potential for the use of electrolysis to provide fuel for FCEVs, and from demand response at the wholesale level, thus enabling greater penetration of renewables. Clean fuel not only reduces pollution and greenhouse gases from the transport sector, but also provides carbon credits as a bonus revenue stream. The analysis addresses both demand and supply in the 2030 and 2050 timeframes.     

Well-to-Wheels analysis of hydrogen production from bio-oil reforming for use in internal combustion engines

The environmental profile of hydrogen depends greatly on the nature of the feedstock and the production process. In this Well-to-Wheels (WTW) study, the environmental impacts of hydrogen production from lignocellulosic biomass via pyrolysis and subsequent steam reforming of bio-oil were evaluated and compared to the conventional production of hydrogen from natural gas steam reforming. Hydrogen was assumed to be used as transportation fuel in an internal combustion engine vehicle. Two scenarios for the provision of lignocellulosic biomass were considered: wood waste and dedicated willow cultivation. The WTW analysis showed that the production of bio-hydrogen consumes less fossil energy in the total lifecycle, mainly due to the renewable nature of the fuel that results in zero energy consumption in the combustion step. The total (fossil and renewable) energy demand is however higher compared to fossil hydrogen, due to the higher process energy demands and methanol used to stabilize bio-oil. Improvements could occur if these are sourced from renewable energy sources. The overall benefit of using a CO₂ neutral renewable feedstock for the production of hydrogen is unquestionable. In terms of global warming, production of hydrogen from biomass through pyrolysis and reforming results in major GHG emissions, ranging from 40% to 50%, depending on the biomass source. The use of cultivated biomass aggravates the GHG emissions balance, mainly due to the N₂O emissions at the cultivation step.     

Hydrogen energy deployment in decarbonizing transportation sector using multi-supply-demand integrated scenario analysis with nonlinear programming — A Shanxi case study

Peaking CO₂ emissions and reaching carbon neutrality create a major role for hydrogen in the transportation field where decarbonization is difficult. Shanxi, as a microcosm of China in the systematic transformation of energy end-use consumption, is selected to investigate the hydrogen energy development forecast for decarbonization in the transportation sector. Multi-supply-demand integrated scenario analysis with nonlinear programming (NLP) model is established to analyze hydrogen energy deployment in varied periods and regions under minimum environmental, energy and economic objectives, to obtain CO₂ emission reduction potential. Results reveal that green hydrogen contributes most to low-carbon hydrogen development strategies. In high-hydrogen demand scenarios, carbon emission reduction potential is significantly higher under environmental objectives, estimated at 297.68 × 10⁴–848.12 × 10⁴ tons (2025–2035). The work provides a strategy to forecast hydrogen energy deployment for transportation decarbonization, being of vital significant guide for planning of hydrogen energy transportation in other regions.     

Global climate-oriented transportation scenarios

This paper develops scenarios whereby CO₂ emissions from the transportation sector are eliminated worldwide by the end of this century. Data concerning the energy intensity and utilization of different passenger and freight transportation modes in 2005, and per capita income, in 10 different socio-economic regions of the world are combined with scenarios of population and per capita GDP to generate scenarios of future transportation energy demand. The impact of various technical options (improvements in the energy intensity of all transportation modes, changes in the proportions of vehicles with different drive trains, and a shift to biomass or hydrogen for the non-electricity energy requirements) and behavioural options (a shift to less energy-intensive LDV market segments, a reduction in total passenger-km of travel per capita, and an increase in the share of less energy-intensive passenger and freight modes of transport) is assessed. To eliminate transportation fossil fuel emissions within this century while limiting the demand for electricity, biofuels or hydrogen to manageable levels requires the simultaneous application of all the technical and behavioural measures considered here, with improvements in vehicle efficiencies and a shift to plug-in hybrid and battery-electric drive trains for light duty vehicles being the most important measures.     

Well-to-wheel analysis of hydrogen fuel-cell electric vehicle in Korea

This study provides methodologies, data collection and results of well-to-wheel greenhouse gas analysis of various H₂ production pathways for fuel-cell electric vehicle (FCEV) in Korea; naphtha cracking, steam methane reforming, electrolysis and coke oven gas purification. The well-to-wheel (WTW) greenhouse gas emissions of FCEV are calculated as 32,571 to 249,332 g-CO₂ eq./GJ or 50.7 to 388.0 g-CO₂ eq./km depending on the H₂ production pathway. The landfill gas (on-site) pathway has the lowest GHG emissions because the carbon credit owing to use landfill gas. The electrolysis with Korean grid mix (on-site) pathway has the highest GHG emissions due to its high emission factor of the power generation process. Furthermore, the results are compared with other powertrain vehicles in Korea such as internal combustion engine vehicle (ICEV), hybrid electric vehicle (HEV) and electric vehicle (EV). The averaged WTW result of FCEV is 35% of ICEV, is 47% of HEV, and is 63% of EV.     

Deployment of fuel cell vehicles in China: Greenhouse gas emission reductions from converting the heavy-duty truck fleet from diesel and natural gas to hydrogen

Hydrogen fuel cells, as an energy source for heavy duty vehicles, are gaining attention as a potential carbon mitigation strategy. Here we calculate the greenhouse gas (GHG) emissions of the Chinese heavy-duty truck fleet under four hydrogen fuel cell heavy-duty truck penetration scenarios from 2020 through 2050. We introduce Aggressive, Moderate, Conservative and No Fuel Cell Vehicle (No FCV) scenarios. Under these four scenarios, the market share of heavy-duty trucks powered by fuel cells will reach 100%, 50%, 20% and 0%, respectively, in 2050. We go beyond previous studies which compared differences in GHG emissions from different hydrogen production pathways. We now combine an analysis of the carbon intensity of various hydrogen production pathways with predictions of the future hydrogen supply structure in China along with various penetration rates of heavy-duty fuel cell vehicles. We calculate the associated carbon intensity per vehicle kilometer travelled of the hydrogen used in heavy-duty trucks in each scenario, providing a practical application of our research. Our results indicate that if China relies only on fuel economy improvements, with the projected increase in vehicle miles travelled, the GHG emissions of the heavy-duty truck fleet will continue to increase and will remain almost unchanged after 2025. The Aggressive, Moderate and Conservative FCV Scenarios will achieve 63%, 30% and 12% reductions, respectively, in GHG emissions in 2050 from the heavy duty truck fleet compared to the No FCV Scenario. Additional reductions are possible if the current source of hydrogen from fossil fuels was displaced with increased use of hydrogen from water electrolysis using non-fossil generated electricity.