Greece

International standards related to cryogenic hydrogen transferring technologies for mobile applications (filling of trucks ships stationary tanks) are missing and there is lack of experience. The European project ELVHYS (Enhancing safety of liquid and vaporized hydrogen transfer technologies in public areas for mobile applications) aims to provide indications on inherently safer and efficient cryogenic hydrogen technologies and protocols in mobile applicati Read More

Hydrogen has received increased attention in the last decades as a green energy carrier and a promising future fuel. The integration of hydrogen as well as the development of cogeneration plants makes the energy sector more eco-friendly and sustainable. The aim of this paper is the investigation of a solar-fed cogeneration system that can produce power and compressed green hydrogen. The examined unit contains a parabolic trough collector solar fiel Read More

The regional parliament of Tyrol in Austria adopted the climate energy and resources strategy “Tyrol 2050 energy autonomous” in 2014 with the aim to become climate neutral and energy autonomous. “Use of own resources before others do or have to do” is the main principle within this long-term strategic approach in which the “power on demand” process is a main building block and the “power-to-hydrogen” process covers the intrinsic lack of a lon Read More

Hydrogen supplementation in diesel Compression Ignition (CI) engines is gaining more attention since it is considered as a feasible solution to tackle the challenges that are related to the emission regulations that will be applied in the forthcoming years. Such a solution is very attractive because it requires only limited modifications to the existing technology of internal combustion CI engines. To this end numerous work on the investigation of an engine’s p Read More

Hydrogen as fuel has been a promising technology toward climate change mitigation efforts. To this end in this paper we analyze the contribution of hydrogen technology to our future environmental goals. It is assumed that hydrogen is being produced in higher efficiency across time and this is simulated on Global Change Assessment Model (GCAM). The environmental restrictions applied are the expected emissions representative concentration pathways (RC Read More

The impact of ship emission reductions can be maximised by considering climate health and environmental effects simultaneously and using solutions fitting into existing marine engines and infrastructure. Several options available enable selecting optimum solutions for different ships routes and regions. Carbon-neutral fuels including low-carbon and carbon-negative fuels from biogenic or non-biogenic origin (biomass waste renewable hydrogen) could rese Read More

The establishment of near-autonomous micro-grids in commercial or public building complexes is gaining increasing popularity. Short-term storage capacity is provided by means of large battery installations or more often by the employees’ increasing use of electric vehicle batteries which are allowed to operate in bi-directional charging mode. In addition to the above short-term storage means a long-term storage medium is considered essential to the opti Read More

Hydrogen sensors especially those operating at high temperatures are essential tools for the emerging hydrogen economy. Monitoring hydrogen under process conditions to control the reactions for detecting confined species is crucial to the safe widespread use and public acceptance of hydrogen as fuel. Hydrogen sensors must have a sensitivity ranging from traces of hydrogen (parts per million (ppm)) up to levels near the lower explosive limit (LEL Read More

Insular networks constitute ideal fields for investment in renewables and storage due to their excellent wind and solar potential as well the high generation cost of thermal generators in such networks. Nevertheless in order to ensure the stability of insular networks network operators impose strict restrictions on the expansion of renewables. Storage systems render ideal solutions for overcoming the aforementioned restrictions unlocking additional renewa Read More

Nowadays with the need for clean and sustainable energy at its historical peak new equipment strategies and methods have to be developed to reduce environmental pollution. Drastic steps and measures have already been taken on a global scale. Renewable energy sources (RESs) are being installed with a growing rhythm in the power grids. Such installations and operations in power systems must also be economically viable over time to attract more Read More

The maritime transportation sector is a large and growing contributor of greenhouse gas and other emissions. Therefore stringent measures have been taken by the International Maritime Organization to mitigate the environmental impact of the international shipping. These lead to the adoption of new technical solutions involving clean fuels such as hydrogen and high efficiency propulsion technologies that is fuel cells. In this framework this paper Read More

Industrial applications of hydrogen are key to the transition towards a sustainable lowcarbon economy. Hydrogen has the potential to decarbonize industrial sectors that currently rely heavily on fossil fuels. Hydrogen with its unique and versatile properties has several in-industrial applications that are fundamental for sustainability and energy efficiency such as the following: (i) chemical industry; (ii) metallurgical sector; (iii) transport; (iv) energy sector; and (v Read More

The necessity for transitioning to renewable energy sources and the intermittent nature of the natural variables lead to the integration of storage units into these projects. In this research paper wind turbines and solar modules are combined with pumped hydro storage batteries and green hydrogen. Energy management strategies are described for five different scenarios of hybrid renewable energy systems based on single or hybrid storage technolo Read More

The depletion of fossil fuel reserves has resulted from their application in the industrial and energy sectors. As a result substantial efforts have been dedicated to fostering the shift from fossil fuels to renewable energy sources via technological advancements in industrial processes. Microalgae can be used to produce biofuels such as biodiesel hydrogen and bioethanol. Microalgae are particularly suitable for hydrogen production due to their rapid gro Read More

Integrated steelworks off-gases are generally exploited to produce heat and electricity. However further valorization can be achieved by using them as feedstock for the synthesis of valuable products such as methane and methanol with the addition of renewable hydrogen. This was the aim of the recently concluded project entitled “Intelligent and integrated upgrade of carbon sources in steel industries through hydrogen intensified synthesis process Read More

The use of liquid hydrogen in maritime applications is expected to grow in the coming years in order to meet the decarbonisation goals that EU countries and countries worldwide have set for 2050. In this context The Norwegian Public Roads Administration commissioned large-scale LH2 dispersion and explosion experiments both indoors and outdoors which were conducted by DNG GL in 2019 to better understand safety aspects of LH2 in the maritime sect Read More

In the present work we present the results of numerical simulations involving the dispersion and combustion of a hydrogen cloud released in an empty tunnel. The simulations were conducted with the use of ADREA-HF CFD code and the results are compared with measurements from experiments conducted by HSE in a tunnel with the exact same geometry. The length of the tunnel is equal to 70 m and the maximum height from the floor is equal to 3.25 m. Hy Read More

Hydrogen valleys are encompassed within a defined geographical region with various technologies across the entire hydrogen value chain. The scope of this study is to analyze and assess the different hydrogen technologies for their application within the hydrogen valley context. Emphasizing on the coupling of renewable energy sources with electrolyzers to produce green hydrogen this study is focused on the most prominent electrolysis technologies incl Read More

This paper presents an innovative approach to fast frequency control in electric grids by leveraging parked fuel cell electric vehicles (FCEVs) especially heavy-duty vehicles such as trucks. Equipped with hydrogen storage tanks and fuel cells these vehicles can be repurposed as dynamic grid-support assets while parked in designated areas. Using an external cable and inverter system FCEVs inject power into the grid by converting DC from fuel cells into AC t Read More

Future liquid hydrogen-powered aircraft requires the design and optimization of a large number of systems and subsystems with cryogenic tanks being one of the largest and most critical. Considering previous space applications these tanks are usually stiffened by internal members such as stringers frames and stiffeners resulting in a complex geometry that leads to an eventual reduction in weight. Cryogenic tanks experience a variety of mechanical and t Read More

The escalating urgency to address climate change has sparked unprecedented interest in green hydrogen as a clean energy carrier. The intermittent nature of Renewable Energy Sources (RES) like wind and solar can introduce unpredictability into the energy supply potentially causing mismatches in the power grid. To this end green hydrogen production can provide a solution by enhancing system flexibility thereby accommodating the fluctuations and st Read More

This study explores the feasibility parameters of a potential investment plan for injecting “green” hydrogen into the existing natural gas supply network in Greece. To this end a preliminary profitability optimization analysis was conducted through key performance indicators such as the cost of hydrogen and the socio-environmental benefit of carbon savings followed by break-even and sensitivity analyses. The identification of the major impact drivers of th Read More

Eco-design is an innovative design methodology that focuses on minimizing the environmental footprint of industries including aviation right from the conceptual and development stages. However rising industrial demand calls for a more comprehensive strategy wherein beyond environmental considerations competitiveness becomes a critical factor supported by additional pillars of sustainability such as economic viability circularity and Read More

The decarbonization of the maritime sector represents a priority in the energy policy agendas of the majority of Countries worldwide and the International Maritime Organization (IMO) has recently revised its strategy aiming for an ambitious zero-emissions scenario by 2050. In these regards there is a broad consensus on hydrogen as one of the most promising clean energy vectors for maritime transport and a key towards that goal. However to date a Read More