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Supporters of hydrogen energy urge scaling up technology and reducing costs for competitiveness. This paper explores how hydrogen energy technologies (HET) are perceived by Australia's general population and considers the way members of the public imagine their role in the implementation of hydrogen energy now and into the future. The study combines a nationally representative survey (n = 403) and semi-structured interviews (n = 30). Results show age and gender relationships with self-reported hydrogen knowledge. Half of the participants obtained hydrogen information from televised media. Strong support was observed for renewable hydrogen, while coal (26%) and natural gas (41%) versions had less backing. Participants sought more safety-related information (41% expressed concern). Most felt uncertain about influencing hydrogen decisions and did not necessarily recognise they had agency beyond their front fence. Exploring the link between political identity and agency in energy decision-making is needed, with energy democracy a potentially productive direction. • Hydrogen's strongest appeal to Australians is its benefit for climate change mitigation. • Although widely accepted, there is limited knowledge about hydrogen in terms of how it is produced or used. • The more people know about hydrogen, the more willing they are to participate in the decision-making process. [ABSTRACT FROM AUTHOR]

The pressure on reducing greenhouse gas emissions has increased since the focus on climate change mitigation has grown. As the human development index is directly related to per capita energy consumption, sustainable energy production with reduced carbon footprint is the essential pathway for cleaner environment. Over numerous existing biological processes, hydrogen production via photo fermentation and photolysis of water is considered a more sustainable and economical method of hydrogen production. While both biological modes suffer from certain limitations, such as low yields and low production rates, practical implementation is still a long way off due to these limitations. The unique properties of nanomaterials (NMs) can help increase the efficiency of the biomass to biohydrogen process in significant ways. Applications of organic and inorganic nanoparticles in photocatalytic and photo fermentative hydrogen production is discussed in this paper. This review reports a wide range of applications of nanomaterials including the details of photo fermentative microorganisms and their mechanism of action. The maximum photo fermentative bio-H 2 production was reported in the presence of SiC–Fe 3 O 4 (3.02 mol H 2 /mol acetate), Ni (41 mol H 2 /mol sugar), graphite-C 3 N 4 (64.2 mol H 2 /mol sugar) whereas photocatalytic bio-H 2 yield was highest when Pd–Ni/CdS (54 mmol/g.h), Ni-MO/g-C 3 N 4 (1785 mmol/g.h) and CuO/TiO 2 (20.3 mmol/g.h) nanoparticles were employed. To design photocatalytic systems for practical and scalable use, the future research should be focused on deeper theoretical knowledge of mechanisms of light harvesting, ± charge separation and transport, surface biochemical reactions, semiconductor–liquid interactions, and reactor dynamics. [Display omitted] • Recent developments for improving water photolysis and photo-fermentation are reviewed. • Applications of organic and inorganic nanoparticles in hydrogen production are discussed. • The working principle and mechanism of hydrogen production are discussed. • The influence of key operating factors are presented. • Scope for future research was presented. [ABSTRACT FROM AUTHOR]

Fuel cell vehicles using green hydrogen as fuel can contribute to the mitigation of climate change. The increasing utilization of those vehicles creates the need for cost efficient hydrogen refueling stations. This study investigates how to build the most cost efficient refueling stations to fuel small fleet sizes of 2, 4, 8, 16 and 32 fuel cell busses. A detailed physical model of a hydrogen refueling station was built to determine the necessary hydrogen storage size as well as energy demand for compression and precooling of hydrogen. These results are used to determine the refueling costs for different station configurations that vary the number of storage banks, their volume and compressor capacity. It was found that increasing the number of storage banks will decrease the necessary total station storage volume as well as energy demand for compression and precooling. However, the benefit of adding storage banks decreases with each additional bank. Hence the cost for piping and instrumentation to add banks starts to outweigh the benefits when too many banks are used. Investigating the influence of the compressor mass flow found that when fueling fleets of 2 or 4 busses the lowest cost can be reached by using a compressor with the minimal mass flow necessary to refill all storage banks within 24 h. For fleets of 8, 16 and 32 busses, using the compressor with the maximum investigated mass flow of 54 kg/h leads to the lowest costs. • Designing the most cost efficient refueling stations to fuel small bus fleets. • New approach to minimize hydrogen fueling costs using a thermodynamic refueling model. • It is cost efficient to use a minimum of 4 cascade storage banks when fueling busses. • A high mass flow compressor is cost efficient for fleet sizes above 4 busses. • Energy demand for compression makes up a significant share of refueling costs. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study is to examine how the options for producing electricity, fuels, and heat in a carbon-constrained world affect the cost-effectiveness of a range of fuels and propulsion technologies in the transportation sector. GET 7.0, a global energy system model with five end-use sectors, is used for the analysis. We find that an energy system dominated either by solar or by nuclear tends to make biofuels in plug-in hybrids cost-effective. If coal with carbon capture and storage (CCS) dominates the energy system, hydrogen cars, rather than plug-in hybrids tend to become cost-effective. Performing a Monte Carlo simulation, we then show that the general features of our results hold for a wide range of assumptions for the costs of vehicle propulsion technologies (e.g., batteries and fuel cells). However, sufficiently large changes in say the battery costs may overturn the impact of changes in the energy supply system, so that plug-in hybrid vehicles become cost-effective even if coal with CCS dominate the energy supply. We conclude that analyses of future energy carriers and propulsion technologies need to consider developments in the energy supply system. [Copyright &y& Elsevier]