Publications

The growing share of renewables in power grids increases the need for backup generators able to compensate production profiles whenever needed. Hydrogen internal combustion engines (H2 ICEs) offer a promising solution in terms of flexibility reduced capital cost and looser requirements on hydrogen purity. These systems are however still not well characterized. This study introduces a zero-dimensional (0D) model for a 100 % hydrogen engine calibrated using experimental data under varying loads and air-fuel ratios. Unlike existing models it proposes validated electrical efficiency data across multiple operating points. Efficiency curves are provided in quadratic and linear forms allowing integration into diverse energy system simulations including linear programming. The model performance is evaluated in a peak-shaving case study using real data from a remote site with limited grid supply. Three engine-generators are used to match single-minute resolution load demand. Compared to typical models that lack validation and ignore part-load efficiency losses the proposed model highlights differences in hydrogen consumption estimation up to 13.4 % thus offering improved accuracy for techno-economic analyses of hydrogen-based systems.

At present transportation energy comes primarily from fossil fuels. In order to mitigate the effects of greenhouse gas emissions it is necessary to transition to low-carbon transportation technologies. These technologies can include battery electric vehicles fuel cell vehicles and biofuel vehicles. This transition includes not only the development and production of suitable vehicles but also the development of appropriate infrastructure. For example in the case of battery electric vehicles this infrastructure would include additional grid capacity for battery charging. For fuel cell vehicles infrastructure could include facilities for the production of suitable electrofuels which again would require additional grid capacity. In the present paper we look at some specific examples of infrastructure requirements for battery electric vehicles and vehicles using hydrogen and other electrofuels in either internal combustion engines or fuel cells. Analysis includes the necessary additional grid capacity energy storage requirements and land area associated with renewable energy generation by solar photovoltaics and wind. The present analysis shows that the best-case scenario corresponds to the use of battery electric vehicles powered by electricity from solar photovoltaics. This situation corresponds to a 47% increase in grid electricity generation and the utilization of 1.7% of current crop land.

In the context of energy interconnection and low-carbon power the power-to-gas (P2G) carbon trading mechanism is integrated into the integrated energy system (IES) model of multi-energy coupling units to achieve lowcarbon economic dispatch considering both the economic and environmental benefits of system operation. First the characteristics of each unit in the system are comprehensively considered and a joint dispatch structure for a regionally integrated energy system is developed including P2G equipment energy source equipment storage equipment and conversion equipment. The working mechanism of P2G is analyzed and its carbon trading model is established. Next a comprehensive energy system optimization model is formulated with the goal of maximizing system operating profit while accounting for carbon transaction costs. Finally Cplex and Yalmip software are used to perform simulation analysis in MATLAB to verify the effectiveness of the proposed model in reducing system carbon emissions through participation in the carbon trading market ensuring system economy and reducing the dependence of the integrated energy system on the external market.

Excessive reliance on traditional energy sources such as coal petroleum and gas leads to a decrease in natural resources and contributes to global warming. Consequently the adoption of renewable energy sources in power systems is experiencing swift expansion worldwide especially in offshore areas. Floating solar photovoltaic (FPV) technology is gaining recognition as an innovative renewable energy option presenting benefits like minimized land requirements improved cooling effects and possible collaborations with hydropower. This study aims to assess the levelized cost of electricity (LCOE) associated with floating solar initiatives in offshore and onshore environments. Furthermore the LCOE is assessed for initiatives that utilize floating solar PV modules within aquaculture farms as well as for the integration of various renewable energy sources including wind wave and hydropower. The LCOE for FPV technology exhibits considerable variation ranging from 28.47 EUR/MWh to 1737 EUR/MWh depending on the technologies utilized within the farm as well as its geographical setting. The implementation of FPV technology in aquaculture farms revealed a notable increase in the LCOE ranging from 138.74 EUR/MWh to 2306 EUR/MWh. Implementation involving additional renewable energy sources results in a reduction in the LCOE ranging from 3.6 EUR/MWh to 315.33 EUR/MWh. The integration of floating photovoltaic (FPV) systems into green hydrogen production represents an emerging direction that is relatively little explored but has high potential in reducing costs. The conversion of this energy into hydrogen involves high final costs with the LCOH ranging from 1.06 EUR/kg to over 26.79 EUR/kg depending on the complexity of the system.

The global need for energy has risen sharply recently. A global shift to clean energy is urgently needed to avoid catastrophic climate impacts. Hydrogen (H2) has emerged as a potential alternative energy source with near-net-zero emissions. In the African continent for sustainable access to clean energy and the transition away from fossil fuels this paper presents a new approach through which waste energy can produce green hydrogen from biomass. Bio-based hydrogen employing organic waste and biomass is recommended using biological (anaerobic digestion and fermentation) processes for scalable cheaper and low-carbon hydrogen. By reviewing all methods for producing green hydrogen dark fermentation can be applied in developed and developing countries without putting pressure on natural resources such as freshwater and rare metals the primary feedstocks used in producing green hydrogen by electrolysis. It can be expanded to produce medium- and long-term green hydrogen without relying heavily on energy sources or building expensive infrastructure. Implementing the dark fermentation process can support poor communities in producing green hydrogen as an energy source regardless of political and tribal conflicts unlike other methods that require political stability. In addition this approach does not require the approval of new legislation. Such processes can ensure the minimization of waste and greenhouse gases. To achieve cost reduction in hydrogen production by 2030 governments should develop a strategy to expand the use of dark fermentation reactors and utilize hot water from various industrial processes (waste energy recovery from hot wastewater).

Integration of polymer electrolyte membrane water electrolyzers (PEMWEs) for clean hydrogen generation requires a robust understanding of the impact cell designs and conditioning protocols have on operation and stability. Here catalyst-coated electrode and catalyst-coated membrane cells employing Pt/C cathode catalyst layer an IrO2 anode catalyst layer with a platinized titanium mesh or a carbon paper with a microporous layer as the porous transport layer were developed. The impact of cell conditioning above and below 0.25 A cm− 2 was investigated using advanced electrochemical impedance spectroscopy analyses and microscopic imaging with the electrochemical response related to physicochemical processes. Operation below 0.25 A cm− 2 prior to operation above 0.25 A cm− 2 resulted in anode corrosion and titanium cation contamination increasing the cell voltage at 1 A cm− 2 by 200 mV compared to uncontaminated cells. Conditioning above 0.25 A cm− 2 led to nonnegligible hydrogen transport resistances due to cathode flooding that resulted in a ca. 50 mV contribution at 1 A cm− 2 and convoluted with the anode impedance response. The presence of a microporous layer increased catalyst utilization but increased the cell voltage by 300 mV at 1 A cm− 2 due to increased anodic mass transport resistances. These results yield critical insights into the impact of PEMWE cell design and operation on corresponding cell performance and stability while highlighting the need for application dependent standardized operating protocols and operational windows.

To reduce hydrogen consumption by hydrogen fuel cell vehicles (HFCVs) an adaptive power-following control strategy based on gated recurrent unit (GRU) neural network operating condition recognition was proposed. The future vehicle speed was predicted based on a GRU neural network and a driving cycle condition recognition model was established based on k-means cluster analysis. By predicting the speed over a specific time horizon feature parameters were extracted and compared with those of typical operating conditions to determine the categories of the parameters thus the adjustment of the power-following control strategy was realized. The simulation results indicate that the proposed control strategy reduces hydrogen consumption by hydrogen fuel cell vehicles (HFCVs) by 16.6% with the CLTC-P driving cycle and by 4.7% with the NEDC driving cycle compared to the conventional power-following control strategy. Additionally the proposed strategy effectively stabilizes the battery’s state of charge (SOC).

This report investigates the status and trend of Renewable Fuels of Non-Biological Origin (RFNBO) except hydrogen which are needed to cover part of the EU’s demand for low carbon renewable fuels in the coming years. The report is an update of the CETO 2023 report. Most of the conversion technologies investigated have been already demonstrated at small-scale and the current EU legislative framework under the recast of the Renewable Energy Directive (EU) 2018/2001 (Directive EU 2023/2413) sets specific targets for their use. As a pre-requisite well-established solid hydrogen supply chains are needed together with carbon capture technologies to provide carbon dioxide as Carbon Capture and Use (CCU). Fuels that may be produced starting from H2 and CO2 or N2 are hydrocarbons alcohols and ammonia. RFNBO may play a crucial role in the energytransition towards decarbonisation especially in hard-to-abate sectors where direct electrification is not possible. In addition most RFNBO can use existing infrastructure. The growing interest in these fuels is witnessed by the many funding programmes which are today available. Moreover EU leads the sector in terms of patents companies and demonstration activities. Finally the report considers the major challenges and the opportunities for a rapid market uptake of such fuels.

The supplement to the standard IGEM/TD/1 gives the additional requirements and qualifications for pipelines transporting hydrogen and hydrogen/natural gas blends (NG/H blends) at pressures at MOP exceeding 7 barg.<br/>Where there is no numbered section in the supplement corresponding to a section in the main document the requirements of the main document apply in full. Where there is a corresponding numbered section in the main document the numbered section in the supplement is either in addition to or replaces the section in the main document.<br/>Repurposing in accordance with the recommendations of this supplement should only be considered for pipelines which have been operated in accordance with the recommendations of the main document for at least 5 years and which have been audited in accordance with the recommendations of clause 12.4.2.1. This requirement is specified so that compliance with the operational and maintenance requirements specified in the main standard is confirmed through records. With respect to pipelines this includes the requirements for MOP affirmation. This requirement is more onerous than the requirement is ASME B31.12 Clause GR-5.2.1[1] which requires that assessment for conversion to hydrogen service shall be assessed at the time of conversion and reassessment of integrity shall be done within 5 years of conversion.<br/>NG/H blends containing more than 10% mol hydrogen are considered to be equivalent to 100 mol.% hydrogen with respect to limits on design stresses and the potential effect on the material properties and damage and defect categories and acceptance levels unless an additional technical evaluation is carried out to qualify the materials (see clause S5.8). It is noted that there is no evidence to confirm that blends containing up to 10 mol.% hydrogen do not cause material degradation but it is considered that the risk is low.<br/>With respect to industry experience with towns gas this product contained 10-20 % carbon monoxide which has been identified as inhibiting the effect of hydrogen on fracture toughness and fatigue crack growth. Therefore the historical experience with town gas is not relevant.

The continuous increase of energy demand with the subsequent huge fossil fuel consumption is provoking dramatic environmental consequences. The main challenge of this century is to develop and promote alternative more eco-friendly energy production routes. In this framework Solid Oxide Cells (SOCs) are a quite attractive technology which could satisfy the users’ energy request working in reversible operation. Two operating modes are alternated: from “Gas to Power” when SOCs work as fuel cells fed with hydrogen-rich mixture to provide both electricity and heat to “Power to Gas” when SOCs work as electrolysers and energy is supplied to produce hydrogen. If solid oxide fuel cells are an already mature technology with several stationary and mobile applications the use of solid oxide electrolyser cells and even more reversible cells are still under investigation due to their insufficient lifetime. Aiming at providing a better understanding of this new technological approach the study presents a detailed description of cell operation in terms of electrochemical behaviour and possible degradation highlighting which are the most commonly used performance indicators. A thermodynamic analysis of system efficiency is proposed followed by a comparison with other available electrochemical devices in order to underline specific solid oxide cell advantages and limitations.