Spain

Biogas and hydrogen (H2 ) are breaking through as alternative energy sources in road transport specifically for heavy-duty vehicles. Until a public network of service stations is deployed for such vehicles the owners of large fleets will need to build and manage their own refueling facilities. Fleet refueling management and remote monitoring at these sites will become key business needs. This article describes the construction of a prototype system capable of solving those needs. During the design and development process of the prototype the standard industry protocols involved in these installations have been considered and the latest expertise in information technology systems has been applied. This prototype has been essential to determine the Strengths Challenges Opportunities and Risks (SCOR) of such a system which is the first step of a more ambitious project. A second stage will involve setting up a pilot study and developing a commercial system that can be widely installed to provide a real solution for the industry.

Urban population and the trend towards online commerce leads to an increase in delivery solution in cities. The growth of the transport sector is very harmful to the environment being responsible for approximately 40% of greenhouse gas emissions in the European Union. The problem is aggravated when transporting perishable foodstuffs as the vehicle propulsion engine (VPE) must power not only the vehicle but also the refrigeration unit. This means that the VPE must be running continuously both on the road and stationary (during delivery) as the cold chain must be preserved. The result is costly (high fuel consumption) and harmful to the environment. At present refrigerated transport does not support full-electric solutions due to the high energy consumption required which motivates the work presented in this article. It presents a turnkey solution of a hydrogen-powered refrigeration system (HPRS) to be integrated into standard light trucks and vans for short-distance food transport and delivery. The proposed solution combines an air-cooled polymer electrolyte membrane fuel cell (PEMFC) a lithium-ion battery and low-weight pressurised hydrogen cylinders to minimise cost and increase autonomy and energy density. In addition for its implementation and integration all the acquisition power and control electronics necessary for its correct management have been developed. Similarly an energy management system (EMS) has been developed to ensure continuity and safety in the operation of the electrical system during the working day while maximizing both the available output power and lifetime of the PEMFC. Experimental results on a real refrigerated light truck provide more than 4 h of autonomy in intensive intercity driving profiles which can be increased if necessary by simply increasing the pressure of the stored hydrogen from the current 200 bar to whatever is required. The correct operation of the entire HPRS has been experimentally validated in terms of functionality autonomy and safety; with fuel savings of more than 10% and more than 3650 kg of CO2/ year avoided.

The need to drastically reduce greenhouse gas emissions is driving the development of existing and new technologies to produce and use hydrogen. Anion exchange membrane electrolysis is one of these rapidly developing technologies and presents promising characteristics for efficient hydrogen production. However the environmental performance and the material criticality of anion exchange membrane electrolysis must be assessed. In this work prospective life cycle assessment and criticality assessment are applied first to identify environmental and material criticality hotspots within the production of anion exchange membrane electrolysis units and second to benchmark hydrogen production against proton exchange membrane electrolysis. From an environmental point of view the catalyst spraying process heavily dominates the ozone depletion impact category while the production of the membrane represents a hotspot in terms of the photochemical ozone formation potential. For the other categories the environmental impacts are distributed across different components. The comparison of hydrogen production via anion exchange membrane electrolysis and proton exchange membrane electrolysis shows that both technologies involve a similar life-cycle environmental profile due to similar efficiencies and the leading role of electricity generation for the operation of electrolysis. Despite the fact that for proton exchange membrane electrolysis much less material is required due to a higher lifetime anion exchange membrane electrolysis shows significantly lower raw material criticality since it does not rely on platinum-group metals. Overall a promising environmental and material criticality performance of anion exchange membrane electrolysis for hydrogen production is concluded subject to the expected technical progress for this technology.

The chemical industry serves as a global economic backbone and it is an intensive consumer of conventional energy. Due to the depletion of fossil fuels and the emission of greenhouse gases it is necessary to analyze energy supply solutions based on renewable energy sources in this industrial sector. Unlike other sectors such as residential or service industries which have been thoroughly analyzed by the scientific community the use of renewable energies in the chemical industry remains comparatively less examined by the scientific community. This article studies the use of an energy supply system based on photovoltaic technology or a PEM fuel cell for a styrene production industry analyzing the integration of energy storage systems such as batteries as well as different uses for the surplus hydrogen produced by the facility. The most interesting conclusions of the article are: (1) the renewable microgrid considered is viable both technically and economically with a discounted payback period between 5.4 and 6.5 years using batteries as an energy storage system; and (2) the use of hydrogen as energy storage system for a styrene industry is not yet a viable option from an economic point of view.

Currently there is a growing interest in increasing the power range of air-cooled fuel cells (ACFCs) as they are cheaper easier to use and maintain than water-cooled fuel cells (WCFCs). However air-cooled stacks are only available up to medium power (<10 kW). Therefore a good solution may be the development of ACFCs consisting of several stacks until the required power output is reached. This is the concept of air-cooled multi-stack fuel cell (AC-MSFC). The objective of this work is to develop a turnkey solution for the integration of AC-MSFCs in renewable microgrids specifically those with high-voltage DC (HVDC) bus. This is challenging because the AC-MSFCs must operate in the microgrid as a single ACFC with adjustable power depending on the number of stacks in operation. To achieve this the necessary power converter (ACFCs operate at low voltages so high conversion rates are required) and control loops must be developed. Unlike most designs in the literature the proposed solution is compact forming a system (AC-MSFCS) with a single input (hydrogen) and a single output (high voltage regulated power or voltage) that can be easily integrated into any microgrid and easily scalable depending on the power required. The developed AC-MSFCS integrates stacks balance of plant data acquisition and instrumentation power converters and local controllers. In addition a virtual instrument (VI)has been developed which connected to the energy management system (EMS) of the microgrid allows monitoring of the entire AC-MSFCS (operating temperature purging cell voltage monitoring for degradation evaluation stacks operating point control and alarm and event management) as well as serving as a user interface. This allows the EMS to know the degradation of each stack and to carry out energy distribution strategies or specific maintenance actions which improves efficiency lifespan and of course saves costs. The experimental results have been excellent in terms of the correct operation of the developed AC-MSFCS. Likewise the accumulated degradation of the stacks was quantified showing cells with a degradation of >80%. The excellent electrical and thermal performance of the developed power converter was also validated which allowed the correct and efficient supply of regulated power (average efficiency above 90%) to the HVDC bus according to the power setpoint defined by the EMS of the microgrid.

Although alkaline water electrolysis (AWE) is the most widespread technology for hydrogen production by electrolysis its electrochemical and fluid dynamic optimization has rarely been addressed simultaneously using Computational Fluid Dynamics (CFD) simulation. In this regard a two-dimensional (2D) CFD model of an AWE cell has been developed using COMSOL® software and then experimentally validated. The model involves transport equations for both liquid and gas phases as well as equations for the electric current conservation. This multiphysics approach allows the model to simultaneously analyze the fluid dynamic and electrochemical phenomena involved in an electrolysis cell. The electrical response was evaluated in terms of polarization curve (voltage vs. current density) at different operating conditions: temperature electrolyte conductivity and electrode-diaphragm distance. For all cases the model fits very well with the experimental data with an error of less than 1% for the polarization curves. Moreover the model successfully simulates the changes on gas profiles along the cell according to current density electrolyte flow rate and electrode-diaphragm distance. The combination of electrochemical and fluid dynamics studies provides comprehensive information and makes the model a promising tool for electrolysis cell design.

The current political scenario and the concerns for global warming have pushed very harsh regulations on conventional propulsion systems based on the use of fossil fuels. New technologies are being promoted but their current technological status needs further research and development for them to become a competitive substitute for the ever-present internal combustion engine. Hydrogen-fueled internal combustion engines have demonstrated the potential of being a fast way to reach full decarbonization of the transport sector but they still have to face some limitations in terms of the operating range of the engine. For this reason the present work evaluates the potential of reaching full load operation on a conventional diesel engine assuming the minimum modifications required to make it work under H2 combustion. This study shows the methodology through which the combustion model was developed and then used to evaluate a multi-cylinder engine representative of the medium to high duty transport sector. The evaluation included different strategies of dilution to control the combustion performance and the results show that the utilization of EGR brings different benefits to engine operation in terms of efficiency improvement and emissions reduction. Nonetheless the requisites defined for the needed turbocharging system are harsher than expected and result in a potential non-conventional technical solution.

The hydrogen sector is envisaged as one of the key enablers of the energy transition that the European Union is facing to accomplish its decarbonization targets. However regarding the technologies that enable the deployment of a hydrogen economy a growing concern exists about potential burden-shifting across sustainability dimensions. In this sense social life cycle assessment arises as a promising methodology to evaluate the social implications of hydrogen technologies along their supply chains. In the context of the European projects eGHOST and SH2E this study seeks to advance on key methodological aspects of social life cycle assessment when it comes to guiding the ecodesign of two relevant hydrogen-related products: a 5 kW solid oxide electrolysis cell stack for hydrogen production and a 48 kW proton-exchange membrane fuel cell stack for mobility applications. Based on the social life cycle assessment results for both case studies under alternative approaches the definition of a product-specific supply chain making use of appropriate cut-off criteria was found to be the preferable choice when addressing system boundaries definition. Moreover performing calculations according to the activity variable approach was found to provide valuable results in terms of social hotspots identification to support subsequent decision-making processes on ecodesign while the direct calculation approach is foreseen as a complement to ease the interpretation of social scores. It is concluded that advancements in the formalization of such suitable practices could foster the integration of social metrics into the sustainable-by-design framework of hydrogen-related products.

The production of biohydrogen with negative CO2 emissions through the steam methane reforming of biomethane coupled with carbon capture and storage represents a promising technology particularly for industries that are difficult to electrify. In spite of the maturity of this technology which is currently employed in the production of grey and blue hydrogen a detailed cost model that considers the entire supply chain is lacking in the literature. This study addresses this gap by applying correlations derived from actual facilities producing grey and blue hydrogen to calculate the CAPEX while exploring various feedstock combinations for biogas generation to assess the OPEX. The analysis also includes logistic aspects such as decentralised biogas production and the transportation and storage of CO2 . The levelized cost of golden hydrogen is estimated to range from EUR 1.84 to 2.88/kg compared to EUR 1.47/kg for grey hydrogen and EUR 1.93/kg for blue hydrogen assuming a natural gas cost of EUR 25/MWh and excluding the CO2 tax. This range increases to between 3.84 and 2.92 with a natural gas cost of EUR 40/MWh with the inclusion of the CO2 tax. A comparison with conventional green hydrogen is performed highlighting both prices and potential thereby offering valuable information for decision-making.

Energy Intensive Industries (EII) are high users of energy and some of these facilities are extremely dependent on Natural Gas for processing heat production. In European countries where Natural Gas is mostly imported from external producers the increase in international Natural Gas prices is making it difficult for some industries to deliver the required financial results. Therefore they are facing complex challenges that could cause their delocalization in regions with lower energy costs. European countries lack on-site Natural Gas resources and the plans to reduce greenhouse gas emissions in the industrial sector make it necessary to find an alternative. Many different processes cannot be electrified and in these cases synthetic methane is one of the solutions and also represents an opportunity to reduce external energy supply dependency. This study analyzes the current development of power-to-gas technological solutions that could be implemented in large industrial consumers to produce Synthetic Methane using Green Hydrogen as a raw source and using Renewable Energy electricity mainly produced with photovoltaic or wind energy. The study also reviews the triple bottom line impact and the current development status and associated costs for each key component of a power-to-gas plant and the requirements to be fulfilled in the coming years to develop a cost-competitive solution available for commercial use.