Applications & Pathways

Today electricity & heat generation transportation and industrial sectors together produce more than 80% of energy-related CO₂ emissions. Hydrogen may be used as an energy carrier and an alternative fuel in the industrial residential and transportation sectors for either heating energy production from fuel cells or direct fueling of vehicles. In particular the use of hydrogen fuel cell vehicles (HFCVs) has the potential to virtually eliminate CO₂ emissions from tailpipes and considerably reduce overall emissions from the transportation sector. Although steam methane reforming (SMR) is the dominant industrial process for hydrogen production environmental concerns associated with CO₂ emissions along with the process intensification and energy optimization are areas that still require improvement. Metallic membrane reactors (MRs) have the potential to address both challenges. MRs operate at significantly lower pressures and temperatures compared with the conventional reactors. Hence the capital and operating expenses could be considerably lower compared with the conventional reactors. Moreover metallic membranes specifically Pd and its alloys inherently allow for only hydrogen permeation making it possible to produce a stream of up to 99.999+% purity.

For smaller and emerging hydrogen markets such as the semiconductor and fuel cell industries Pd-based membranes may be an appropriate technology based on the scales and purity requirements. In particular at lower hydrogen production rates in small-scale plants MRs with CCUS could be competitive compared to centralized H₂ production. On-site hydrogen production would also provide a self-sufficient supply and further circumvent delivery delays as well as issues with storage safety. In addition hydrogen-producing MRs are a potential avenue to alleviate carbon emissions. However material availability Pd cost and scale-up potential on the order of 1.5 million m3/day may be limiting factors preventing wider application of Pd-based membranes.

Regarding the economic production of hydrogen the benchmark by the year 2020 has been determined and set in place by the U.S. DOE at less than $2.00 per kg of produced hydrogen. While the established SMR process can easily meet the set limit by DOE other carbon-free processes such as water electrolysis electron beam radiolysis and gliding arc technologies do not presently meet this requirement. In particular it is expected that the cost of hydrogen produced from natural gas without CCUS will remain the lowest among all of the technologies while the hydrogen cost produced from an SMR plant with solvent-based carbon capture could be twice as expensive as the conventional SMR without carbon capture. Pd-based MRs have the potential to produce hydrogen at competitive prices with SMR plants equipped with carbon capture.

Despite the significant improvements in the electrolysis technologies the cost of hydrogen produced by electrolysis may remain significantly higher in most geographical locations compared with the hydrogen produced from fossil fuels. The cost of hydrogen via electrolysis may vary up to a factor of ten depending on the location and the electricity source. Nevertheless due to its modular nature the electrolysis process will likely play a significant role in the hydrogen economy when implemented in suitable geographical locations and powered by renewable electricity.

This review provides a critical overview of the opportunities and challenges associated with the use of the MRs to produce high-purity hydrogen with low carbon emissions. Moreover a technoeconomic review of the potential methods for hydrogen production is provided and the drawbacks and advantages of each method are presented and discussed.

In Norway where nearly 100% of the power is hydroelectric it is natural to consider water electrolysis as the main production method of hydrogen for zero-emission transport. In a start-up market with low demand for hydrogen one may find that small-scale WE-based hydrogen production is more cost-efficient than large-scale production because of the potential to reach a high number of operating hours at rated capacity and high overall system utilization rate. Two case studies addressing the levelized costs of hydrogen in local supply systems have been evaluated in the present work: (1) Hydrogen production at a small-scale hydroelectric power plant (with and without on-site refuelling) and (2) Small hydrogen refuelling station for trucks (with and without on-site hydrogen production). The techno-economic calculations of the two case studies show that the levelized hydrogen refuelling cost at the small-scale hydroelectric power plant (with a local station) will be 141 NOK/kg while a fleet of 5 fuel cell trucks will be able to refuel hydrogen at a cost of 58 NOK/kg at a station with on-site production or 71 NOK/kg at a station based on delivered hydrogen. The study shows that there is a relatively good business case for local water electrolysis and supply of hydrogen to captive fleets of trucks in Norway particularly if the size of the fleet is sufficiently large to justify the installation of a relatively large water electrolyzer system (economies of scale). The ideal concept would be a large fleet of heavy-duty vehicles (with a high total hydrogen demand) and a refuelling station with nearly 100% utilization of the installed hydrogen production capacity.

The 30 integrated steel plants operating in the European Union (EU) are among the largest single-point CO₂ emitters in the region. The deployment of bioenergy with carbon capture and storage (bio-CCS) could significantly reduce their emission intensities. In detail the results demonstrate that CO₂ emission reduction targets of up to 20% can be met entirely by biomass deployment. A slow CCS technology introduction on top of biomass deployment is expected as the requirement for emission reduction increases further. Bio-CCS could then be a key technology particularly in terms of meeting targets above 50% with CO₂ avoidance costs ranging between €60 and €100 tCO2−1 at full-scale deployment. The future of bio-CCS and its utilisation on a larger scale would therefore only be viable if such CO₂ avoidance cost were to become economically appealing. Small and medium plants in particular would economically benefit from sharing CO₂ pipeline networks. CO₂ transport however makes a relatively small contribution to the total CO₂ avoidance cost. In the future the role of bio-CCS in the European iron and steelmaking industry will also be influenced by non-economic conditions such as regulations public acceptance realistic CO₂ storage capacity and the progress of other mitigation technologies.

The work is dedicated to the possibility of using hydrogen-powered vehicles in urban transport systems. Due to the need to look for alternative solutions for vehicles with conventional drive in cities hydrogen-powered cars are one of the practical possibilities of realizing the sustainable transport assumptions and independence from oil imports - which is one of the main priorities of the European Union. This paper presents a literature analysis the analysis of the current state and development of use hydrogen-powered vehicles in the world.<br/>The article refers to the possibilities of use hydrogen-vehicles in different ways of mobility: individual vehicles taxis and shared mobility. In addition the author focused on showing the advantages and disadvantages of using hydrogen-powered vehicles in urban transport systems.

In 2016 for the first time a polymer electrolyte fuel cell free of Pt electrocatalysts was shown to deliver more than 0.5 W cm-2 of peak power density from H2 and air (CO2 free). This was achieved with a silver-based oxygen reduction (ORR) cathode and a Pd-CeO2 hydrogen oxidation reaction (HOR) anodic electrocatalyst. The poor kinetics of the HOR under alkaline conditions is a considerable challenge to Anion Exchange Membrane Fuel Cell (AEMFC) development as high Pt loadings are still required to achieve reasonable performance. Previously the ameliorative combination of Pd and CeO2 nanocomposites has been exploited mostly in heterogeneous catalysis where the positive interaction is well documented. Carbon supported PdCeO2 HOR catalysts have now been prepared by different synthetic techniques and employed in AEMFCs as alternative to Pt and PtRu standards. Important research has also been recently reported delving into the origin of the HOR enhancement on Pd-CeO2. Such work has highlighted the importance of the bifunctional mechanism of the HOR at high pHs. Carefully prepared nano-structures of Pd and CeO2 that promote the formation of the Pd-O-Ce interface provide optimal binding of both Had and OHad species aspects which are crucial for enhanced HOR kinetics. This review paper discusses the recent advances in Pd-CeO2 electrocatalysts for AEMFC anodes.

Biomass derived porous nanostructured nitrogen doped carbon (PNC) has been extensively investigated as the electrode material for electrochemical catalytic reactions and rechargeable batteries. Biomass with and without containing nitrogen could be designed and optimized to prepare PNC via hydrothermal carbonization pyrolysis and other methods. The presence of nitrogen in carbon can provide more active sites for ion absorption improve the electronic conductivity increase the bonding between carbon and sulfur and enhance the electrochemical catalytic reaction. The synthetic methods of natural biomass derived PNC heteroatomic co- or tri-doping into biomass derived carbon and the application of biomass derived PNC in rechargeable Li/Na batteries high energy density Li–S batteries supercapacitors metal-air batteries and electrochemical catalytic reaction (oxygen reduction and evolution reactions hydrogen evolution reaction) are summarized and discussed in this review. Biomass derived PNCs deliver high performance electrochemical storage properties for rechargeable batteries/supercapacitors and superior electrochemical catalytic performance toward hydrogen evolution oxygen reduction and evolution as promising electrodes for electrochemical devices including battery technologies fuel cell and electrolyzer.

Hydrogen evolution reaction (HER) plays a key role in generating clean and renewable energy. As the most effective HER electrocatalysts Pt group catalysts suffer from severe problems such as high price and scarcity. It is highly desirable to design and synthesize sustainable HER electrocatalysts to replace the Pt group catalysts. Due to their low cost high abundance and high activities cobalt-incorporated N-doped nanocarbon hybrids are promising candidate electrocatalysts for HER. In this report we demonstrated a robust and eco-friendly host-guest approach to fabricate metallic cobalt nanoparticles embedded in N-doped carbon fibers derived from natural silk fibers. Benefiting from the one-dimensional nanostructure the well-dispersed metallic cobalt nanoparticles and the N-doped thin graphitized carbon layer coating the best Co-based electrocatalyst manifests low overpotential (61 mV@10 mA/cm2) HER activity that is comparable with commercial 20% Pt/C and good stability in acid. Our findings provide a novel and unique route to explore high-performance noble-metal-free HER electrocatalysts.

Hydrogen is widely recognised as an important option for future road transportation but a widespread infrastructure must be developed if the potential for hydrogen is to be achieved. This paper and related appendices which can be downloaded as Supplementary material present a mixed-integer linear programming model (called SHIPMod) that optimises a hydrogen supply chains for scenarios of hydrogen fuel demand in the UK including the spatial arrangement of carbon capture and storage infrastructure. In addition to presenting a number of improvements on past practice in the literature the paper focuses attention on the importance of assumptions regarding hydrogen demand. The paper draws on socio-economic data to develop a spatially detailed scenario of possible hydrogen demand. The paper then shows that assumptions about the level and spatial dispersion of hydrogen demand have a significant impact on costs and on the choice of hydrogen production technologies and distribution mechanisms.

Presently the fulfilment of world’s energy demand highly relies on the fossil fuel i.e. coal oil and natural gas. Fossil fuels pose threat to environment and biological systems on the earth. Usage of these fuels leads to an increase in the CO2 content in the atmosphere that causes global warming and undesirable climatic changes. Additionally these are limited sources of energy those will eventually dwindle. There is huge urge of identifying and utilizing the renewable energy resources to replace these fossil fuels in the near future as it is expected to have no impact on environment and thus would enable one to provide energy security. Hydrogen is one of the most desirable fuel capable of replacing vanishing hydrocarbons. In this review we present the status of energy demands recent advances in renewable energy and the prospects of hydrogen as a future fuel are highlighted. It gives a broad overview of different energy systems and mainly focuses on different technologies and their reliability for the production of hydrogen in present and future.

This paper presents techno-economic modelling results of a nationwide hydrogen fuel supply chain (HFSC) that includes renewable hydrogen production transportation and dispensing systems for fuel cell electric buses (FCEBs) in Ireland. Hydrogen is generated by electrolysers located at each existing Irish wind farm using curtailed or available wind electricity. Additional electricity is supplied by on-site photovoltaic (PV) arrays and stored using lithium-ion batteries. At each wind farm sizing of the electrolyser PV array and battery is optimised system design to obtain the minimum levelised cost of hydrogen (LCOH). Results show the average electrolyser capacity factor is 64% after the integration of wind farm-based electrolysers with PV arrays and batteries. A location-allocation algorithm in a geographic information system (GIS) environment optimises the distributed hydrogen supply chain from each wind farm to a hypothetical hydrogen refuelling station in the nearest city. Results show that hydrogen produced transported and dispensed using this system can meet the entire current bus fuel demand for all the studied cities at a potential LCOH of 5–10 €/kg by using available wind electricity. At this LCOH the future operational cost of FCEBs in Belfast Cork and Dublin can be competitive with public buses fuelled by diesel especially under carbon taxes more reflective of the environmental impact of fossil fuels.