Life cycle assessment of various hydrogen production methods

A comprehensive life cycle assessment (LCA) is reported for five methods of hydrogen production, namely steam reforming of natural gas, coal gasification, water electrolysis via wind and solar electrolysis, and thermochemical water splitting with a Cu–Cl cycle. Carbon dioxide equivalent emissions and energy equivalents of each method are quantified and compared. A case study is presented for a hydrogen fueling station in Toronto, Canada, and nearby hydrogen resources close to the fueling station. In terms of carbon dioxide equivalent emissions, thermochemical water splitting with the Cu–Cl cycle is found to be advantageous over the other methods, followed by wind and solar electrolysis. In terms of hydrogen production capacities, natural gas steam reforming, coal gasification and thermochemical water splitting with the Cu–Cl cycle methods are found to be advantageous over the renewable energy methods.     

Life cycle greenhouse emissions of compressed natural gas–hydrogen mixtures for transportation in Argentina

We have developed a model to assess the life cycle greenhouse emissions of compressed natural gas–hydrogen (CNG–H₂) mixtures used for transportation in Argentina. The overall fuel life cycle is assessed through a well-to-wheel (WTW) analysis for different hydrogen generation and distribution options. The combustion stage in road vehicles is modeled using the COPERT IV model. Hydrogen generation options include classical steam methane reforming (SMR) and water electrolysis (WE) in central plants and distributed facilities at the refueling stations. Centralized hydrogen generation by electrolysis in nuclear plants as well as the use of solar photovoltaic and wind electricity is also considered. Hydrogen distribution options include gas pipeline and refrigerated truck transportation for liquefied hydrogen. A total number of fifteen fuel pathways are studied; in all the cases the natural gas–hydrogen mixture is made at the refueling station. The use of WE using nuclear or wind electricity appears to be less contaminant that the use of pure CNG.     

Comparative assessment of greenhouse gas mitigation of hydrogen passenger trains

This paper examines a comparative assessment in terms of CO₂ emissions from a hydrogen passenger train in Ontario, Canada, particularly comparing four specific propulsion technologies: (1) conventional diesel internal combustion engine (ICE), (2) electrified train, (3) hydrogen ICE, and (4) hydrogen PEM fuel cell (PEMFC) train. For the electrified train, greenhouse gases from electricity generation by natural gas and coal-burning power plants are taken into consideration. Several hydrogen production methods are also considered in this analysis, i.e., (1) steam methane reforming (SMR), (2) thermochemical copper–chlorine (Cu–Cl) cycle supplied partly by waste heat from a nuclear plant, (3) renewable energies (solar and wind power) and (4) a combined renewable energy and copper–chlorine cycle. The results show that a PEMFC powertrain fueled by hydrogen produced from combined wind energy and a copper–chlorine plant is the most environmentally friendly method, with CO₂ emissions of about 9% of a conventional diesel train or electrified train that uses a coal-burning power plant to generate electricity. Hydrogen produced with a thermochemical cycle is a promising alternative to further reduce the greenhouse gas emissions. By replacing a conventional diesel train with hydrogen ICE or PEMFC trains fueled by Cu-Cl based-hydrogen, the annual CO₂ emissions are reduced by 2260 and 3318 tonnes, respectively. A comparison with different types of automobile commuting scenarios to carry an equivalent number of people as a train is also conducted. On an average basis, only an electric car using renewable energy-based electricity that carries more than three people may be competitive with hydrogen trains.     

Life cycle environmental impact comparison of solid oxide fuel cells fueled by natural gas,hydrogen, ammonia and methanol for combined heat and power generation

This study aims to provide a comprehensive environmental life cycle assessment of heat and power production through solid oxide fuel cells (SOFCs) fueled by various chemical feeds namely; natural gas, hydrogen, ammonia and methanol. The life cycle assessment (LCA) includes the complete phases from raw material extraction or chemical fuel synthesis to consumption in the electrochemical reaction as a cradle-to-grave approach. The LCA study is performed using GaBi software, where the selected impact assessment methodology is ReCiPe 1.08. The selected environmental impact categories are climate change, fossil depletion, human toxicity, water depletion, particulate matter formation, and photochemical oxidant formation. The production pathways of the feed gases are selected based on the mature technologies as well as emerging water electrolysis via wind electricity. Natural gas is extracted from the wells and processed in the processing plant to be fed to SOFC. Hydrogen is generated by steam methane reforming method using the natural gas in the plant. Methanol is also produced by steam methane reforming and methanol synthesis reaction. Ammonia is synthesized using the hydrogen obtained from steam methane reforming and combined with nitrogen from air in a Haber-Bosch plant. Both hydrogen and ammonia are also produced via wind energy-driven decentralized electrolysis in order to emphasize the cleaner fuel production. The results of this study show that feeding SOFC systems with carbon-free fuels eliminates the greenhouse gas emissions during operation, however additional steps required for natural gas to hydrogen, ammonia and methanol conversion, make the complete process more environmentally problematic. However, if hydrogen and ammonia are produced from renewable sources such as wind-based electricity, the environmental impacts reduce significantly, yielding about 0.05 and 0.16 kg CO₂ eq., respectively, per kWh electricity generation from SOFC.     

An analysis of hydrogen production from renewable electricity sources

Three aspects of producing hydrogen via renewable electricity sources are analyzed to determine the potential for solar and wind hydrogen production pathways: a renewable hydrogen resource assessment, a cost analysis of hydrogen production via electrolysis, and the annual energy requirements of producing hydrogen for refueling. The results indicate that ample resources exist to produce transportation fuel from wind and solar power. However, hydrogen prices are highly dependent on electricity prices. For renewables to produce hydrogen at $2 kg⁻¹, using electrolyzers available in 2004, electricity prices would have to be less than $0.01 kWh⁻¹. Additionally, energy requirements for hydrogen refueling stations are in excess of 20 GWh/year. It may be challenging for dedicated renewable systems at the filling station to meet such requirements. Therefore, while plentiful resources exist to provide clean electricity for the production of hydrogen for transportation fuel, challenges remain to identify optimum economic and technical configurations to provide renewable energy to distributed hydrogen refueling stations.     

Greenhouse gas emissions reduction by use of wind and solar energies for hydrogen and electricity production: Economic factors

This study addresses economic aspects of introducing renewable technologies in place of fossil fuel ones to mitigate greenhouse gas emissions. Unlike for traditional fossil fuel technologies, greenhouse gas emissions from renewable technologies are associated mainly with plant construction and the magnitudes are significantly lower. The prospects are shown to be good for producing the environmentally clean fuel hydrogen via water electrolysis driven by renewable energy sources. Nonetheless, the cost of wind- and solar-based electricity is still higher than that of electricity generated in a natural gas power plant. With present costs of wind and solar electricity, it is shown that, when electricity from renewable sources replaces electricity from natural gas, the cost of greenhouse gas emissions abatement is about four times less than if hydrogen from renewable sources replaces hydrogen produced from natural gas. When renewable-based hydrogen is used in a fuel cell vehicle instead of gasoline in a IC engine vehicle, the cost of greenhouse gas emissions reduction approaches the same value as for renewable-based electricity only if the fuel cell vehicle efficiency exceeds significantly (i.e., by about two times) that of an internal combustion vehicle. It is also shown that when 6000 wind turbines (Kenetech KVS-33) with a capacity of 350 kW and a capacity factor of 24% replace a 500-MW gas-fired power plant with an efficiency of 40%, annual greenhouse gas emissions are reduced by 2.3 megatons. The incremental additional annual cost is about $280 million (US). The results provide a useful approach to an optimal strategy for greenhouse gas emissions mitigation.     

Evaluation of hydrogen production methods using the Analytic Hierarchy Process

In this paper, seven common hydrogen production processes are evaluated using the Analytic Hierarchy Process (AHP) in respect to five criteria. The processes to be evaluated are steam methane reforming (SMR), partial oxidation of hydrocarbons (POX), coal gasification (CG), biomass gasification (BG), the combination of photovoltaics and electrolysis (PV–EL), the combination of wind power and electrolysis (W–EL) and the combination of hydropower and electrolysis (H–EL). The selected criteria that were used in the evaluation, for each of the seven hydrogen production processes are CO₂ emissions, operation and maintenance costs, capital cost, feedstock cost and hydrogen production cost. According to the evaluation, the processes that combine renewable energy sources with electrolysis (PV–EL, W–EL and H–EL) rank higher in classification than conventional processes (SMR, POX, CG and BG).     

Comparative assessment of hydrogen production methods from renewable and non-renewable sources

In this study, we present a comparative environmental impact assessment of possible hydrogen production methods from renewable and non-renewable sources with a special emphasis on their application in Turkey. It is aimed to study and compare the performances of hydrogen production methods and assess their economic, social and environmental impacts, The methods considered in this study are natural gas steam reforming, coal gasification, water electrolysis via wind and solar energies, biomass gasification, thermochemical water splitting with a Cu–Cl and S–I cycles, and high temperature electrolysis. Environmental impacts (global warming potential, GWP and acidification potential, AP), production costs, energy and exergy efficiencies of these eight methods are compared. Furthermore, the relationship between plant capacity and hydrogen production capital cost is studied. The social cost of carbon concept is used to present the relations between environmental impacts and economic factors. The results indicate that thermochemical water splitting with the Cu–Cl and S–I cycles become more environmentally benign than the other traditional methods in terms of emissions. The options with wind, solar and high temperature electrolysis also provide environmentally attractive results. Electrolysis methods are found to be least attractive when production costs are considered. Therefore, increasing the efficiencies and hence decreasing the costs of hydrogen production from solar and wind electrolysis bring them forefront as potential options. The energy and exergy efficiency comparison study indicates the advantages of biomass gasification over other methods. Overall rankings show that thermochemical Cu–Cl and S–I cycles are primarily promising candidates to produce hydrogen in an environmentally benign and cost-effective way.     

Potential importance of hydrogen as a future solution to environmental and transportation problems

Air pollution is a serious public health problem throughout the world, especially in industrialized and developing countries. In industrialized and developing countries, motor vehicle emissions are major contributors to urban air quality. Hydrogen is one of the clean fuel options for reducing motor vehicle emissions. Hydrogen is not an energy source. It is not a primary energy existing freely in nature. Hydrogen is a secondary form of energy that has to be manufactured like electricity. It is an energy carrier. Hydrogen has a strategic importance in the pursuit of a low-emission, environment-benign, cleaner and more sustainable energy system. Combustion product of hydrogen is clean, which consists of water and a little amount of nitrogen oxides. Hydrogen has very special properties as a transportation fuel, including a rapid burning speed, a high effective octane number, and no toxicity or ozone-forming potential. It has much wider limits of flammability in air than methane and gasoline. Hydrogen has become the dominant transport fuel, and is produced centrally from a mixture of clean coal and fossil fuels (with C-sequestration), nuclear power, and large-scale renewables. Large-scale hydrogen production is probable on the longer time scale. In the current and medium term the production options for hydrogen are first based on distributed hydrogen production from electrolysis of water and reforming of natural gas and coal. Each of centralized hydrogen production methods scenarios could produce 40 million tons per year of hydrogen. Hydrogen production using steam reforming of methane is the most economical method among the current commercial processes. In this method, natural gas feedstock costs generally contribute approximately 52–68% to the final hydrogen price for larger plants, and 40% for smaller plants, with remaining expenses composed of capital charges. The hydrogen production cost from natural gas via steam reforming of methane varies from about 1.25 US$/kg for large systems to about 3.50 US$/kg for small systems with a natural gas price of 6 US$/GJ. Hydrogen is cheap by using solar energy or by water electrolysis where electricity is cheap, etc.     

Analysis of effects of the hydrogen supply chain on the Korean energy system

The scope of hydrogen energy is being extended in the Republic of Korea as a national innovative growth engine to overcome environmental problems, particularly climate change. The effects of this expansion on the energy system and national greenhouse gas (GHG) emissions are expected to vary greatly depending on the hydrogen energy supply chain scenario. Accordingly, in this study, the energy and environmental effects of hydrogen energy supply chain scenarios on the national energy system were analyzed quantitatively using the TIMES model, a representative bottom-up energy system analysis model. The scenarios were defined in terms of three perspectives: the development level of key technologies, contribution of future renewable energy to the power generation sector, and relative importance of each hydrogen production method portfolio. All scenarios were based on the policies being considered by the Korean government. The results of the scenario analyses show, among others, that green hydrogen, i.e., water electrolysis-oriented hydrogen production, consumes a fairly large amount of electricity. Therefore, from the perspective of the entire national energy system, the transition of the power sector to renewable energy, mainly solar and wind energies, and the advancement of water electrolysis are required to reduce the national GHG emissions.     

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.     

Comparative life cycle assessment of hydrogen and other selected fuels

A streamlined life cycle assessment (LCA) is reported of a nuclear-based copper–chlorine (Cu–Cl) hydrogen production cycle, including estimates of fossil fuel energy use and greenhouse gas (GHG) emissions. Calculations revealed that the process requires 474 kJ of fossil fuel energy per MJ of hydrogen, which is less than for other hydrogen production processes. Moreover, GHG emissions are estimated to be 27 gCO₂e per MJ of hydrogen, which is only slightly higher than the corresponding value for wind-based hydrogen production. A sensitivity analysis demonstrated that the performance of the system could be further improved at higher yields of hydrogen. Although the system significantly outperformed fossil-based gasoline and hydrogen production pathways, the integrated nuclear and thermochemical cycle still requires significant research and development before commercialization is possible.     

Wind energy,electricity, and hydrogen in the Netherlands

The curbing of greenhouse gases (GHG) is an important issue on the international political agenda. The substitution of fossil fuels by renewable energy sources is an often-advocated mitigation strategy. Wind energy is a potential renewable energy source. However, wind energy is not reliable since its electricity production depends on variable weather conditions. High wind energy penetration rates lead to losses due to power plant operation adjustments to wind energy. This research identifies the potential energetic benefits of integrated hydrogen production in electricity systems with high wind energy penetration. This research concludes that the use of system losses for hydrogen production via electrolysis is beneficial in situations with ca. 8 GW or more wind energy capacity in the Netherlands. The 2020 Dutch policy goal of 6 GW will not benefit from hydrogen production in terms of systems efficiency. An ancillary beneficial effect of coupling hydrogen production with wind energy is to relieve the high-voltage grid.     

A review on hydrogen production and utilization: Challenges and opportunities

Environment-friendly, safe and reliable energy supplies are indispensable to society for sustainable development and high life quality where even though social, environmental, political and economic challenges may play a vital role in their provision. Our continuously growing energy demand is driven by extensive growth in economic development and population and places an ever-increasing burden on fossil fuel utilization that represent a substantial percentage of this increasing energy demand but also creates challenges associated with increased greenhouse gas (GHG) emissions and resource depletion. Such challenges make the global transition obligatory from conventional to renewable energy sources. Hydrogen is emerging as a new energy vector outside its typical role and receiving more recognition globally as a potential fuel pathway, as it offers advantages in use cases and unlike synthetic carbon-based fuels can be truly carbon neutral or even negative on a life cycle basis. This review paper provides critical analysis of the state-of-the-art in blue and green hydrogen production methods using conventional and renewable energy sources, utilization of hydrogen, storage, transportation, distribution and key challenges and opportunities in the commercial deployment of such systems. Some of the key promising renewable energy sources to produce hydrogen, such as solar and wind, are intermittent; hydrogen appears to be the best candidate to be employed for multiple purposes blending the roles of fuel energy carrier and energy storage modality. Furthermore, this study offers a comparative assessment of different non-renewable and renewable hydrogen production systems based on system design, cost, global warming potential (GWP), infrastructure and efficiency. Finally the key challenges and opportunities associated with hydrogen production, storage, transportation and distribution and commercial-scale deployment are addressed.     

Multi-hub hydrogen refueling station with on-site and centralized production

In recent decades, the consequences of climate changes due to greenhouse gas (GHG) emissions have become ever more impactful, forcing international authorities to find green solutions for sustainable economic development. In this regard, one of the global targets is the reduction of fossil fuels utilization in the transport sector to encourage the diffusion of more environmentally friendly alternatives. Among them, hydrogen is emerging as a viable candidate since it is a potentially emission-free fuel when produced by exploiting renewable energy sources (RES). Nevertheless, to allow widespread use of this gas in the transport sector, several technoeconomic barriers, including production cost, and lack of distribution and storage infrastructure, have to be overcome. Distributed hydrogen production via renewable energy-powered electrolysis could be an effective solution to reduce cost and lead to economies of scale. In this study a multi-hub configuration with on-site production from PV-powered electrolysis and centralized production from steam methane reforming (SMR) is proposed. In particular, an infrastructure network for a bus refueling station located in Lazio is considered as a case study. First, each hub, composed of PV panels, an electrolyzer, a compression system, high-pressure and low-pressure storages, and hydrogen dispensers with chiller, is modeled in a Matlab/Simulink environment. Then, a design perturbation analysis is carried out to determine the impact of the configuration on the refueling station performance in terms of carbon emissions levels and the Levelized Cost of hydrogen (LCOH). The results show a significant influence of the station size on the economic performance highlighting significant benefits (reduction up to 40% in the LCOH) for a 80 bus HUB with a saturating trend towards larger sizes. CO₂ emissions per unit mass of hydrogen are kept limited for all the stations thanks to the synergistic effects of SMR and Electrolyzer. Interconnecting more than one station each other further benefits can be achieved from the environmental perspective (savings up to 5 tons of CO₂ are demonstrated for a typical summer case study).     

Dynamic simulation and lifecycle assessment of hydrogen fuel cell electric vehicles considering various hydrogen production methods

In this research study, a real model of a hydrogen fuel cell vehicle is simulated using Simcenter Amesim software. The software used for vehicle simulation enabled dynamic simulation, resulting in more precise simulation. Furthermore, considering that fuel cell degradation is one of the significant challenges confronting fuel cell vehicle manufacturers, we examined the impact of fuel cell degradation on the performance of hydrogen vehicles. According to the findings, a hydrogen vehicle with a degraded fuel cell consumes 14.3% more fuel than a fresh fuel cell hydrogen vehicle. A comprehensive life cycle assessment (LCA) is also performed for the designed hydrogen vehicle. The results of the hydrogen vehicle life cycle assessment are compared with a gasoline vehicle to fully understand the effect of hydrogen vehicles in reducing air emissions. The methods considered for hydrogen production included natural gas reforming, electrolysis, and thermochemical water splitting method. Furthermore, because the source of electricity used for electrolysis has a significant impact on the life cycle emission of a hydrogen vehicle, three different power sources were considered in this assessment. Finally, while a hydrogen vehicle with a degraded fuel cell emits lower carbon dioxide (CO₂) than a gasoline vehicle, the emitted CO₂ from this vehicle using hydrogen from electrolysis is approximately 25% higher than that of a new hydrogen vehicle.     

An integrated approach to hydrogen economy in Sicilian islands

CNR–ITAE is developing several hydrogen and fuel cell demonstration and research projects, each intended to be part of a larger strategy for hydrogen communities settling in small Sicilian islands. These projects involve vehicle design, hydrogen production from renewable energy sources and methane, as well as implementation strategies to develop a hydrogen and renewable energy economy. These zero emission lightweight vehicles feature regenerative braking and advanced power electronics to increase efficiency. Moreover, to achieve a very easy-to-use technology, a very simple interface between driver and the system is under development, including fault-recovery strategies and GPS positioning for car-rental fleets. Also marine applications have been included, with tests on PEFC applied on passenger ships and luxury yacht as power system for on-board loads. In marine application, it is under study also an electrolysis hydrogen generator system using seawater as hydrogen carrier. For stationary and automotive applications, the project includes a hydrogen refuelling station powered by renewable energy (wind or/and solar) and test on fuel processors fed with methane, in order to make the power generation self-sufficient, as well as to test the technology and increase public awareness toward clean energy sources.     

Life cycle cost analysis: A case study of hydrogen energy application on the Orkney Islands

Hydrogen can compensate for the intermittent nature of some renewable energy sources and encompass the options of supplying renewables to offset the use of fossil fuels. The integrating of hydrogen application into the energy system will change the current energy market. Therefore, this paper deploys the life cycle cost analysis of hydrogen production by polymer electrolyte membrane (PEM) electrolysis and applications for electricity and mobility purposes. The hydrogen production process includes electricity generated from wind turbines, PEM electrolyser, hydrogen compression, storage, and distribution by H₂ truck and tube trailer. The hydrogen application process includes PEM fuel cell stacks generating electricity, a H₂ refuelling station supplying hydrogen, and range extender fuel cell electric vehicles (RE-FCEVs). The cost analysis is conducted from a demonstration project of green hydrogen on a remote archipelago. The methodology of life cycle cost is employed to conduct the cost of hydrogen production and application. Five scenarios are developed to compare the cost of hydrogen applications with the conventional energy sources considering CO₂ emission cost. The comparisons show the cost of using hydrogen for energy purposes is still higher than the cost of using fossil fuels. The largest contributor of the cost is the electricity consumption. In the sensitivity analysis, policy supports such as feed-in tariff (FITs) could bring completive of hydrogen with fossil fuels in current energy market.     

A techno-economic analysis of decentralized electrolytic hydrogen production for fuel cell vehicles

Hydrogen from decentralized water electrolysis is one of the main fuelling options considered for future fuel cell vehicles. In this study, a model is developed to determine the key technical and economic parameters influencing the competitive position of decentralized electrolytic hydrogen. This model incorporates the capital, maintenance and energy costs of water electrolysis, as well as a monetary valuation of the associated greenhouse gas (GHG) emissions. It is used to analyze the competitive position of electrolytic hydrogen in three specific locations with distinct electricity mix: Vancouver, Los Angeles and Paris. Using local electricity prices and fuel taxes, electrolytic hydrogen is found to be commercially viable in Vancouver and Paris. Hydrogen storage comes out as the most important technical issue. But more than any technical issue, electricity prices and fuel taxes emerge as the two dominant issues affecting the competitive position of electrolytic hydrogen. The monetary valuation of GHG emissions, based on a price of $20/ton of CO₂, is found to be generally insufficient to tilt the balance in favor of electrolytic hydrogen.     

Environmental life cycle feasibility assessment of hydrogen as an automotive fuel in Western Australia

A life cycle assessment has been undertaken in order to determine the environmental feasibility of hydrogen as an automotive fuel in Western Australia. The criterion for environmental feasibility has been defined as having life cycle impacts equal to or lower than those of petrol. Two hydrogen production methods have been analysed. The first is steam methane reforming (SMR), which uses natural gas (methane) as a feedstock. The second method analysed is alkaline electrolysis (AE), a mature technology that uses water as a feedstock. The life cycle emissions and impacts were assessed per kilometre of vehicle travel.