Publications

Russia’s invasion of Ukraine has reaffirmed the importance of scaling up renewable energy to decarbonise Europe’s economy while rapidly reducing its exposure to foreign fossil fuel suppliers. Therefore the question of sources of flexibility to support a fully decarbonised European energy system is becoming even more critical in light of a renewable-dominated energy system. We developed and used a Pan-European energy system model to systematically assess and quantify sources of flexibility to meet deep decarbonisation targets. The electricity supply sector and electricity-based end-use technologies are crucial in achieving deep decarbonisation. Other low-carbon energy sources like biomethane hydrogen synthetic e-fuels and bioenergy with carbon capture and storage will also play a role. To support a fully decarbonised European energy system by 2050 both temporal and spatial flexibility will be needed. Spatial flexibility achieved through investments in national electricity networks and cross-border interconnections is crucial to support the aggressive roll-out of variable renewable energy sources. Cross-border trade in electricity is expected to increase and in deep decarbonisation scenarios the electricity transmission capacity will be larger than that of natural gas. Hydrogen storage and green hydrogen production will play a key role in providing traditional inter-seasonal flexibility and intraday flexibility will be provided by a combination of electrical energy storage hydrogen-based storage solutions (e.g. liquid H2 and pressurised storage) and hybrid heat pumps. Hydrogen networks and storage will become more critical as we move towards the highest decarbonisation scenario. Still the need for natural gas networks and storage will decrease substantially.

The large-scale deployment of technologies that enable energy from renewables is essential for a successful transition to a carbon-neutral future. While photovoltaic panels are one of the main technologies commonly used for harvesting energy from the Sun storage of renewable solar energy still presents some challenges and often requires integration with additional devices. It is believed that hydrogen – being a perfect energy carrier – can become one of the broadly utilised storage alternatives that would effectively mitigate the energy supply and demand issues associated with the intermittent nature of renewable energy sources. Current pathways in the development of green technologies indicate the need for more sustainable material utilisation and more efficient device operation. To address this requirement integration of various technologies for renewable energy harvesting conversion and storage in a single device appears as an advantageous option. From the hydrogen economy perspective systems driven by green solar electricity that allow for (photo)electrochemical water splitting would generate hydrogen with the minimal CO2 footprint. If at the same time one of the device electrodes could store the generated gas and release it on demand the utilisation of critical and often costly elements would be reduced with possible gain in more effective device operation. Although conceptually attractive this cross-disciplinary concept has not gained yet enough attention and only limited number of experimental setups have been designed tested and reported. This review presents the first exhaustive overview and critical examination of various laboratory-scale prototype setups that attempt to combine both the hydrogen production and storage processes in a single unit via integration of a metal hydride-based electrode into a photoelectrochemical cell. The architectures of presented configurations enables direct solar energy to hydrogen conversion and its subsequent storage in a single device which – in some cases – can also release the stored (hydrogen) energy on demand. In addition this work explores perspectives and challenges related with the potential upscaling of reviewed solar-to-hydrogen storage systems trying to map and indicate the main future directions of their technological development and optimization. Finally the review also combines information and expertise scattered among various research fields with the aim of stimulating much-needed exchange of knowledge to accelerate the progress in the development and deployment of optimum green hydrogen-based solutions.

Climate change and the pressure to decarbonize as well as energy security concerns have drawn the attention of policymakers and the industry to hydrogen energy. To advance the hydrogen economy at a global scale research and innovation progress is of significant importance among others. However previous studies have provided only limited quantitative evidence of the effects of research and innovation on the formation of a global hydrogen market. Instead they postulate rather than empirically support this relationship. Therefore this study analyzes the effects of research and innovation measured by scientific publications patents and standards on bilateral hydrogen trade flows for 32 countries between 1995 and 2019 in a gravity model of trade using regression analyses and Poisson Pseudo Maximum Likelihood (PPML) estimation. The main results of the PPML estimation show that research and innovation progress is indeed associated with increased trade especially with patenting and (international) standardization enhancing hydrogen export volumes. As policy implications we derive that increased public R&D funding can help increase the competitiveness of hydrogen energy and boost market growth along with infrastructure support and harmonized standards and regulations.

Hydrogen is experiencing a resurgence in energy transition debates. Before representing a solution however the existing hydrogen economy is still a climate change headache: over 99 % of production depends on fossil fuels oil refining accounts for 42 % of demand and its transportation is intertwined with fossil infrastructure like natural gas pipelines. This article investigates the path-dependent dynamics shaping the hydrogen economy and its interconnections with the oil and gas industry. It draws on the global production networks (GPN) approach and political economy research to provide a comprehensive review of current and prospective enduses of hydrogen modes of transport networks of industrial actors and state strategies along the major production facilities and holders of intellectual property rights. The results presented in this article suggest that the superimposition of private agendas may jeopardise the viability of future energy systems and requires counterbalancing forces to override the negative consequences of path-dependent energy transitions.

With the adjustment of energy structure the utilization of hydrogen energy has been widely attended. China’s carbon neutrality targets make it urgent to change traditional coal-fired power generation. The paper investigates the combustion of pulverized coal blended with hydrogen to reduce carbon emissions. In terms of calorific value the pulverized coal combustion with hydrogen at 1% 5% and 10% blending ratios is investigated. The results show that there is a significant reduction in CO2 concentration after hydrogen blending. The CO2 concentration (mole fraction) decreased from 15.6% to 13.6% for the 10% hydrogen blending condition compared to the non-hydrogen blending condition. The rapid combustion of hydrogen produces large amounts of heat in a short period which helps the ignition of pulverized coal. However as the proportion of hydrogen blending increases the production of large amounts of H2O gives an overall lower temperature. On the other hand the temperature distribution is more uniform. The concentrations of O2 and CO in the upper part of the furnace increased. The current air distribution pattern cannot satisfy the adequate combustion of the fuel after hydrogen blending.

The core of carbon neutrality is the energy structure adjustment and economic structure transformation. Hydrogen energy as a kind of clean energy with great potential has provided important support for the implementation of the carbon peaking and carbon neutrality goals of China. How to achieve the large-range safe and reliable transportation of hydrogen energy with good economic benefits remains the key to limiting the development of hydrogen energy. Using the existing natural gas pipeline network can save many infrastructure construction costs to transport hydrogen-blended natural gas. However due to great differences in the physical and chemical properties of hydrogen and natural gas the transportation of hydrogen-blended natural gas will bring safety risks to the pipeline network operation to a certain extent. In this paper the influences of pipeline transportation of hydrogen-blended natural gas on existing pipelines and parts along the pipelines are analyzed from two aspects of pipe compatibility and hydrogen blending ratio and the safety of pipeline transportation of hydrogen-blended natural gas is summarized from two aspects of leakage and accumulation as well as combustion and explosion. In addition the integrity management of hydrogen-blended natural gas pipelines and the existing relevant standards and specifications are reviewed. This paper points out the shortcomings of current hydrogen-blended natural gas pipeline transportation and gives some relevant suggestions. Hopefully this work can provide a useful reference for developing a hydrogen-blended natural gas pipeline transportation system.

The ecological transition in the transport sector is a major challenge to tackle environmental pollution and European legislation will mandate zero-emission new cars from 2035. To reduce the impact of petrol and diesel vehicles much emphasis is being placed on the potential use of synthetic fuels including electrofuels (e-fuels). This research aims to examine a levelised cost (LCO) analysis of e-fuel production where the energy source is renewable. The energy used in the process is expected to come from a photovoltaic plant and the other steps required to produce e-fuel: direct air capture electrolysis and Fischer-Tropsch process. The results showed that the LCOe-fuel in the baseline scenario is around 3.1 €/l and this value is mainly influenced by the energy production component followed by the hydrogen one. Sensitivity scenario and risk analyses are also conducted to evaluate alternative scenarios and it emerges that in 84% of the cases LCOe-fuel ranges between 2.8 €/l and 3.4 €/l. The findings show that the current cost is not competitive with fossil fuels yet the development of e-fuels supports environmental protection. The concept of pragmatic sustainability incentive policies technology development industrial symbiosis economies of scale and learning economies can reduce this cost by supporting the decarbonisation of the transport sector.

At present most fuel cell engines are single-stack systems and high-power single-stack systems have bottlenecks in meeting the power requirements of heavy-duty trucks mainly because the increase in the single active area and the excessive number of cells will lead to poor distribution uniformity of water gas and heat in the stack which will cause local attenuation and reduce the performance of the stack. This paper introduces the design concept of internal combustion engine takes three-stack fuel cell engine as an example designs multi-stack fuel cell system scheme and serialized high-voltage scheme. Through Intelligent control technology of independent hydrogen injection based on multi-stack coupling the hydrogen injection inflow of each stack is controlled online according to the real-time anode pressure to achieve accurate fuel injection of a single stack and ensure the consistency between multiple stacks. proves the performance advantage of multi-stack fuel cell engine through theoretical designintelligent control and test verification and focuses on analyzing the key technical problems that may exist in multi-stack consistency. The research results provide a reference for the design of multi-stack fuel cell engines and have important reference value for the powertrain design of long-distance heavy-duty and high-power fuel cell trucks.

Green hydrogen has recently gained importance as a key element in the transition to a low-carbon energy future sparking a boom in possible production regions. This article aims at situating incipient hydrogen production in the Argentine province of Río Negro within a global production network (GPN). The early configuration of the hydrogen-GPN includes several stakeholders and is contested in many ways. To explore the possible materialization of the hydrogen economy in Argentina this article links GPN literature to the concept of sociotechnical imaginaries. In so doing this study finds three energy imaginaries linked to hydrogen development: First advocates of green hydrogen (GH2) project a sociotechnical imaginary in which GH2 is expected to promote scientific and technological progress. Second proponents of blue hydrogen point to Vaca Muerta and the role of natural gas for energy autonomy. Third opponents of the GH2 project question the underlying growth and export model emphasizing conservation and domestic energy sovereignty. The competition between different capital fractions i.e. green and fossil currently poses the risk of pro-fossil path decisions and lock-in effects. Current power constellations have led to the replacement of green with low-emission resulting in the promotion of multi-colored hydrogen. This is particularly evident in the draft for the new national hydrogen law and the actors involved in defining the national hydrogen strategy. The conceptual combination of actors and their interests their current power relations and the sociotechnical imaginaries they deploy illustrates how Argentina's energy future is already being shaped today.

Trains have been a crucial part of modern transport and their high energy efficiency and low greenhouse gas emissions make them ideal candidates for the future transport system. Transitioning from diesel trains to hydrogen fuel cell electric trains is a promising way to decarbonize rail transport. That’s because the fuel cell electric trains have several advantages over other electric trains such as lower life-cycle emissions and shorter refueling time than battery ones and less requirements for wayside infrastructure than the ones with overhead electric wires. However hydrogen fuel technology still needs to be advanced in areas including hydrogen production storage refueling and on-board energy management. Currently there are several pilot projects of hydrogen fuel cell electric trains across the globe especially in developed countries including one commercialized and permanent route in Germany. The experiences from the pilot projects will promote the technological and economic feasibility of hydrogen fuel in rail transport.