Publications

Current safety codes and technical standards related to Japanese hydrogen refueling stations (HRSs) have been established based on qualitative risk assessment and quantitative effectiveness validation of safety measures for more than ten years. In the last decade there has been significant development in the technologies and significant increment in operational experience related to HRSs. We performed a quantitative risk assessment (QRA) of the HRS model representing Japanese HRSs with the latest information in the previous study. The QRA results were obtained by summing risk contours derived from each process unit. They showed that the risk contours of 10-3 and 10-4 per year were confined within the HRS boundaries whereas those of 10-5 and 10-6 per year are still present outside the HRS boundaries. Therefore we analyzed the summation of risk contours derived from each unit and identified the largest risk scenarios outside the station. The HRS model in the previous study did not consider fire and blast protection walls which could reduce the risks outside the station. Therefore we conducted a detailed risk analysis of the identified scenarios using 3D structure modeling. The heat radiation and temperature rise of jet fire scenarios that pose the greatest risk to the physical surroundings in the HRS model were estimated in detail based on computational fluid dynamics with 3D structures including fire protection walls. Results show that the risks spreading outside the north- west- and east-side station boundaries are expected to be acceptable by incorporating the fire protection wall into the Japanese HRS model.

An energy transition is in progress around the globe notably led by an increase in the deployment of renewable energy and a shift toward less emissions-intense options notably in the transportation sector. This research investigates the potential role that new transportation options namely flying vehicles may play toward progressing the energy transition. As flying vehicles are a relatively new technology yet to penetrate the market it is also prudent to consider the ethical legal and social issues (ELSI) associated with their implementation alongside the potential energy and environmental impacts. Through a review of ELSI and energy and environmental literature we identify research gaps and identify how flying vehicles may impact upon the energy transition over time. Our research identifies several critical aspects of both ELSI and energy and environmental academia relevant to the future deployment of flying vehicles and describes a deployment timeline and the resultant societal outcomes. We find that flying vehicles could drive the energy transition and the hydrogen economy and that their widespread adoption could engender shared socio-environmental benefits. Our findings are relevant to transportation and environmental policymakers and identify critical considerations for the planned introduction of new shared transportation options to the market conducive to a sustainable energy transition.

The fuel cell game is not new and for many it is has been a long time coming. Few know this better than Ballard Power Systems the third ever founded Fuel Cell company that has operated since the 1970s. On the show we ask Nicolas Pocard about Ballards history and why this time the market is different for fuel cell companies.

The podcast can be found on their website

The deployment of low-carbon hydrogen in gas grids comes with strategic benefits in terms of energy system integration and decarbonization. However hydrogen thermophysical properties substantially differ from natural gas and pose concerns of technical and regulatory nature. The present study investigates the blending of hydrogen into distribution gas networks focusing on the steady-state fluid dynamic response of the grids and gas quality compliance issues at increasing hydrogen admixture levels. Two blending strategies are analyzed the first of which involves the supply of NG–H2 blends at the city gate while the latter addresses the injection of pure hydrogen in internal grid locations. In contrast with traditional case-specific analyses results are derived from simulations executed over a large number (i.e. one thousand) of synthetic models of gas networks. The responses of the grids are therefore analyzed in a statistical fashion. The results highlight that lower probabilities of violating fluid dynamic and quality restrictions are obtained when hydrogen injection occurs close to or in correspondence with the system city gate. When pure hydrogen is injected in internal grid locations even very low volumes (1% vol of the total) may determine gas quality violations while fluid dynamic issues arise only in rare cases of significant hydrogen injection volumes (30% vol of the total).

To meet ambitious targets for greenhouse gas emissions reduction in the 2035-2050 timeframe hydrogen has been identified as a clean “green” fuel of interest. In comparison to fossil fuel use the burning of hydrogen results in zero CO2 emissions and it can be obtained from renewable energy sources. In addition to zero CO2 emissions hydrogen has several other attractive properties such as higher gravimetric energy content and wider flammability limits than most fossil fuels. However there are practical limitations to its widespread use at present which include low volumetric energy density in the gaseous state and high well-to-wheel costs when compared to fossil fuel production and distribution. In this paper a review is undertaken to identify the current state of development of key areas of the hydrogen network such as production distribution storage and power conversion technology. At present high technology costs still are a barrier to widespread hydrogen adoption but it is envisioned that as scale of production increases then costs are likely to fall. Technical barriers to a hydrogen economy adoption are not as significant as one might think as key technologies in the hydrogen network are already mature with working prototypes already developed for technologies such as liquid hydrogen composite cryotanks and proton exchange membrane fuel cells. It is envisioned that with continuous investment to achieve requisite scale that a hydrogen economy could be realised sooner rather than later with novel concepts such as turboelectric distributed propulsion enabled by a shift to hydrogen-powered network.

The hydrogen storage pressure in fuel cell vehicles has been increased from 35 MPa to 70 MPa in order to accommodate longer driving range. On the downside such pressure increase results in significant temperature rise inside the hydrogen tank during fast filling at a fueling station which may pose safety issues. Installation of a chiller often mitigates this concern because it cools the hydrogen gas before its deposition into the tank. To address both the energy efficiency improvement and safety concerns this paper proposed an on-board cold thermal energy storage (CTES) system cooled by expanded hydrogen. During the driving cycle the proposed system uses an expander instead of a pressure regulator to generate additional power and cold hydrogen gas. Moreover CTES is equipped with phase change materials (PCM) to recover the cold energy of the expanded hydrogen gas which is later used in the next filling to cool the high-pressure hydrogen gas from the fueling station.

In order to improve the energy efficiency of the internal combustion engine and replace fossil fuel with alternative fuels a concept of the methanol-syngas engine was proposed and the prototype was developed. Gasoline and dissociated methanol gas (GDM) were used as dual fuels and the engine performance was investigated by simulation and experiments. Dissociated methanol gas is produced by recycling the exhaust heat. The performance and combustion process was studied and compared with the gasoline engine counterpart. There is 1.9% energy efficiency improvement and 5.5% fuel consumption reduction under 2000r/min 100 N · m working condition with methanol substitution ratio of 10%. In addition the engine efficiency further improves with an increase of dissociated methanol gas substitution ratio because of the increased heating value of the fuel and effects of hydrogen. The peak pressure in the cylinder and the peak heat release rate of the GDM engine are higher than that of the original gasoline engine with a phase closer to the top dead center (TDC). Therefore blending hydrogen-rich gas in the spark-ignition engine can recycle the exhaust heat and improve the thermal efficiency of the engine.

About 25 years ago Bogdanovic and Schwickardi (B. Bogdanovic M. Schwickardi: J. Alloys Compd. 1–9 253 (1997) discovered the catalyzed release of hydrogen from NaAlH4 . This discovery stimulated a vast research effort on light hydrides as hydrogen storage materials in particular boron hydrogen compounds. Mg(BH4 )2 with a hydrogen content of 14.9 wt % has been extensively studied and recent results shed new light on intermediate species formed during dehydrogenation. The chemistry of B3H8 − which is an important intermediate between BH4 − and B12H12 2− is presented in detail. The discovery of high ionic conductivity in the high-temperature phases of LiBH4 and Na2B12H12 opened a new research direction. The high chemical and electrochemical stability of closo-hydroborates has stimulated new research for their applications in batteries. Very recently an all-solid-state 4 V Na battery prototype using a Na4 (CB11H12)2 (B12H12) solid electrolyte has been demonstrated. In this review we present the current knowledge of possible reaction pathways involved in the successive hydrogen release reactions from BH4 − to B12H12 2− and a discussion of relevant necessary properties for high-ionic-conduction materials.

Mass-produced off-the-shelf automotive air compressors cannot be directly used for boosting a fuel cell vehicle (FCV) application in the same way that they are used in internal combustion engines since the requirements are different. These include a high pressure ratio a low mass flow rate a high efficiency requirement and a compact size. From the established fuel cell types the most promising for application in passenger cars or light commercial vehicle applications is the proton exchange membrane fuel cell (PEMFC) operating at around 80 ◦C. In this case an electric-assisted turbocharger (E-turbocharger) and electric supercharger (single or two-stage) are more suitable than screw and scroll compressors. In order to determine which type of these boosting options is the most suitable for FCV application and assess their individual merits a co-simulation of FCV powertrains between GT-SUITE and MATLAB/SIMULINK is realised to compare vehicle performance on the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) driving cycle. The results showed that the vehicle equipped with an E-turbocharger had higher performance than the vehicle equipped with a two-stage compressor in the aspects of electric system efficiency (+1.6%) and driving range (+3.7%); however for the same maximal output power the vehicle’s stack was 12.5% heavier and larger. Then due to the existence of the turbine the E-turbocharger led to higher performance than the single-stage compressor for the same stack size. The solid oxide fuel cell is also promising for transportation application especially for a use as range extender. The results show that a 24-kWh electric vehicle can increase its driving range by 252% due to a 5 kW solid oxide fuel cell (SOFC) stack and a gas turbine recovery system. The WLTP driving range depends on the charge cycle but with a pure hydrogen tank of 6.2 kg the vehicle can reach more than 600 km.

A “combined world” of fuel cell electric vehicles (FCEVs) and battery electric vehicles (BEVs) will create a greener transportation sector faster and cheaper than one of the solutions alone. Hydrogen Council with analytical support from McKinsey and Company published a report that highlights the complementary roles of FCEVs and BEVs in a decarbonised transportation sector.

The analysis found that each solution has comparable systemic efficiencies and similar CO2 life cycle intensity. From the vehicle user perspective FCEVs and BEVs will provide the flexibility and convenience to meet their specific context of use and geographic location. Additionally the costs of two supporting infrastructure for FCEVs and BEVs is cheaper than one infrastructure network primarily due to the reduced peak loads and avoidance of costly upgrades on the electricity grid. The report’s messages were developed in dialogue with the Observatory Group which consisted of representatives of government agencies and academia as well as associations and companies active in sectors like regenerative electricity generation electricity grid equipment manufacturing electric vehicle charging fleet management.

The paper can be found on their website.