Authors: P. Chen, Y. Zhang, S. Harati, S. Walker, K. Dearn
Abstract:
Wave and tidal energy are promising renewable resources for offshore electricity generation, with hydrogen serving as a storable and transportable energy carrier. This study presents an integrated offshore hydrogen production system combining full-scale hybrid wave-tidal energy converters (HWTEC), hybrid supercapacitor-battery energy storage system, proton exchange membrane (PEM) electrolyzers, and subsea underground hydrogen storage (UHS). A system-level co-simulation framework is developed to capture the coupled dynamics of energy conversion, storage, and hydrogen production under stochastic marine conditions. UHS significantly reduces platform space requirements for hydrogen storage, enabling higher on-platform hydrogen capacity. A case study using 2024 UK wave and tidal data evaluates a conceptual platform with six HWTECs and PEM electrolyzers with combined average output of 64.8 kW. Results indicate a representative hydrogen production rate of 1.4 kg/h and an estimated annual yield of 12.4 t, with specific energy consumption of 46.8–55.7 kWh/kgH2 and exergy efficiency of 21.4–25.3%. The system demonstrates enhanced power continuity, efficient conversion of intermittent offshore energy, and feasibility for grid-independent operation. The proposed framework advances beyond previous device-level studies by integrating multiple subsystems with real marine inputs, providing a scalable and practical tool for design, optimization, and performance assessment of offshore hybrid renewable hydrogen platforms.
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Authors: Danny Pudjianto, Hossein Ameli, Spyros Giannelos
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Departing from silo approaches, this paper presents a holistic methodology for assessing the benefits of integrating optimally selected electrolysers within a Net Zero Energy system. The optimisation addresses large-scale multi-energy system planning, considering the interactions among low-carbon generation technologies, such as renewables, energy storage, and smart demand response, while accounting for the spatial and temporal dynamics of energy sources and demand. The value of electrolysers is evaluated through a comparison of system capacity portfolios and operational costs between scenarios with and without electrolysers. The analysis focuses on future energy scenarios in Great Britain, exploring various assumptions to identify the value drivers and needs for electrolysers and their optimal distribution in the system. Results highlight the role of electrolysers in enhancing system balancing and energy storage capabilities, promoting sector coupling between electricity and hydrogen systems. This synergy enables low-cost hydrogen storage and generation, which is essential for providing ancillary services and ensuring energy system resilience. The paper also explores insights from sensitivity studies regarding the impacts of varying costs for low-carbon technologies, gas prices, and the flexibility provided by end-use customers and distributed storage.
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Authors: Alma Ademovic Tahirovic, Hossein Ameli, Goran Strbac
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Environmental pressures have long driven the shift toward non-fossil fuel alternatives in energy systems. However, the impact of climate change on reliability of renewable sources has received limited attention. Brazil’s energy system, dominated by hydropower (71%), faces increasing strain from prolonged dry conditions and growing peak demand. Only half of this hydro capacity is reservoir-type dispatchable, increasing reliability concerns. While expansions in wind, solar, and natural gas have been pursued, they introduce volatility and logistical complexity, with imposed constraints of domestic reserves and imports. Biomass emerges as a flexible and viable alternative, particularly in decentralized applications. It offers emission reductions and cost savings when derived from locally sourced agricultural residues, in form of biogas and biomethane energy streams. This paper applies the extended Combined Gas and Electricity Network model to assess infrastructure interdependencies and diversification strategies under Brazil’s energy transition. Results show that small-scale biomass, paired with energy efficiency and demand management, enhances resilience. Energy efficiency, despite higher upfront costs, provides long-term savings and emission reductions. The findings highlight the need for diversified, low-emission strategies with energy conservation as the foundation of sustainable development.
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Authors: Alma Ademovic Tahirovic, Predrag Djapic, Hossein Ameli, Goran Strbac
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The energy transition is expanding beyond electricity to address high-emission sectors such as heat and transport. While electrification is key to decarbonisation, it risks overloading infrastructure and increasing costs for end-users. Flexibility remains a critical barrier to integrating low-carbon technologies at scale. This paper explores the role of cross-vector flexibility, the coordinated use of electricity, heat, and transport systems, in reducing infrastructure strain and supporting decarbonisation. Using the REMeDY district energy business model, applied to Southend-on-Sea, the study evaluates distribution network impacts. Results show that cross-vector flexibility delivers greater value than decentralised approaches, offering reduced reinforcement needs, enhanced system flexibility, and lower investment costs. Stand-alone applications provide limited benefits, whereas integrated, whole-systems deployment achieves significantly higher value. The findings highlight the importance of strategic local planning and holistic energy management. Follow-up analyses further confirm the potential of cross-vector flexibility to reduce system costs and support efficient, scalable decarbonisation.
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Authors:
Abstract:
Deriving accurate cost projections associated with producing hydrogen within the context of an energy-export paradigm is a challenging feat due to non-deterministic nature of weather systems. Many research efforts employ deterministic models to estimate costs, which could be biased by the innate ability of these models to see the future. To this end we present the findings of a multistage stochastic model of hydrogen production for energy export (using liquid hydrogen or ammonia as energy vectors), the findings of which are compared to that of a deterministic programme. Our modelling found that the deterministic model consistently underestimated the price relative to the non-deterministic approach by $ 0.08, 0.10 kg-1(H2) (when exposed to the exact same amount of weather data) and saw a standard deviation 40% higher when modelling the same time horizon. In addition to comparing modelling paradigms, different grid-operating strategies were explored in their ability to mitigate three critical co-sensitive factors of the production facility: high-cost hydrogen storage, uncertainty in weather forecasting and sluggish production processes. We found that a grid-wheeling strategy substantially reduces the production cost for a solar system (by 16% and 21% for LH2 and NH3, respectively) due to its ability to guarantee the return of energy borrowed overnight during the day, but was not effective for the wind system, due to the non-periodic nature of aeolian weather patterns.
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Authors: M. Li., K. Zhu., Y. Lu., Q. Zhao., K. Yin
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Rising global demand for sustainable, low-carbon energy has driven growing interest in integrating diverse renewable and clean energy sources into building systems. This study proposes a innovative multi-energy hybrid system that integrates combined cooling, heating, and power technology with absorption refrigeration and ground source heat pumps, powered by a combination of solar, wind, geothermal, hydrogen, and natural gas. A coupled TRNSYS-DeST dynamic simulation is developed to capture hourly dynamic interactions between multiple energy inputs and HVAC subsystems over a full year. A comprehensive 4E (energy, exergy, economic, and environmental) lifecycle assessment is conducted, considering seasonal load profiles and evaluating the system’s performance over its entire lifecycle. Furthermore, a multi-objective optimization using response surface methodology is carried out to identify optimal system configurations, aiming to balance efficiency, cost, and emissions. The optimized system achieves an energy efficiency of 84.2 %, a primary energy saving rate of 72.2 %, a power self-sufficiency rate of 125 %, a levelized cost of product of 0.022 $/kWh, a net present value of 341,221.58 a sustainability index of 7.88, and a pollutant emission reduction rate of 33.32 %. These results demonstrate the feasibility and substantial potential of multi-energy complementary systems in delivering low-carbon, cost-effective, and sustainable energy solutions for buildings.
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Authors: , , , , , Yiji Lu
Abstract:
Rising global demand for sustainable, low-carbon energy has driven growing interest in integrating diverse renewable and clean energy sources into building systems. This study proposes a innovative multi-energy hybrid system that integrates combined cooling, heating, and power technology with absorption refrigeration and ground source heat pumps, powered by a combination of solar, wind, geothermal, hydrogen, and natural gas. A coupled TRNSYS-DeST dynamic simulation is developed to capture hourly dynamic interactions between multiple energy inputs and HVAC subsystems over a full year. A comprehensive 4E (energy, exergy, economic, and environmental) lifecycle assessment is conducted, considering seasonal load profiles and evaluating the system’s performance over its entire lifecycle. Furthermore, a multi-objective optimization using response surface methodology is carried out to identify optimal system configurations, aiming to balance efficiency, cost, and emissions. The optimized system achieves an energy efficiency of 84.2 %, a primary energy saving rate of 72.2 %, a power self-sufficiency rate of 125 %, a levelized cost of product of 0.022 $/kWh, a net present value of 341,221.58 a sustainability index of 7.88, and a pollutant emission reduction rate of 33.32 %. These results demonstrate the feasibility and substantial potential of multi-energy complementary systems in delivering low-carbon, cost-effective, and sustainable energy solutions for buildings.
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Authors: , , , , , ,
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The growing accumulation of municipal solid waste and the urgent need for low-carbon liquid fuels present significant challenges and opportunities for sustainable thermal energy systems. This study addresses the problem of efficiently converting municipal solid waste into green methanol while maximizing energy utilization and minimizing environmental impacts. An integrated waste-to-methanol system is evaluated by the thermodynamic analysis, combining municipal solid waste incineration, carbon dioxide capture, renewable electricity-driven water electrolysis for hydrogen production, methanol synthesis, and multi-level waste heat recovery using dual organic Rankine cycle systems. Comprehensive thermodynamic, economic, and environmental analyses are conducted to assess system performance and identify key influencing parameters. The system processes 1000 kg/h of municipal solid waste and produces 11.24 tons/day of high-purity methanol with a mass fraction of 99.76%, while simultaneously generating 419.1 kW of net electricity. The overall energy efficiency and exergy efficiency reach 30.63% and 29.32%, respectively. The carbon emission intensity is 0.1204 kg CO2/kg MeOH, and the levelized methanol production cost is estimated at 701.49 $/ton. Sensitivity analysis reveals that turbine inlet conditions, carbon dioxide liquefaction temperature, and methanol extraction ratio are the dominant parameters influencing system efficiency and economic performance. The results demonstrate that integrating municipal solid waste utilization with renewable hydrogen production and waste heat recovery provides a promising pathway for efficient and low-carbon methanol production compared with conventional methanol production, offering both environmental and techno-economic quantitative evidence of performance improvements.
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Authors: Si Chen, Benoit Couraud, Sonam Norbu, Merlinda Andoni, Zafar Iqbal, Sasa Djokic, Desen Kirli,
Satria Putra Kanugrahan, Paolo Cherubini, Susan Krumdieck, Valentin Robu, David Flynn
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The integration of renewable energy sources (RES) and the convergence of transport electrification, creates a significant challenge for distribution network management e.g. voltage and frequency violations, particularly in rural and remote areas. This paper investigates how smart charging of electric vehicles (EVs) can help reduce renewable energy curtailment and alleviate stress on local distribution networks. We implement a customised AC Optimal Power Flow (AC OPF) formulation which integrates into the optimisation an indicator reflecting the social impact of flexibility from EV users, based on the analysis of historical EV charging behaviours. The contribution of EV owners to reducing wind curtailment is optimised to enhance the acceptability of flexibility procurement, as the method targets EV users whose charging habits are most likely to align with flexibility requirements. Our method integrates social, technological, and economic perspectives with optimal flexibility coordination, and utilises clustering of EVs through a k-means algorithm. To ensure scalability, we introduce a polar coordinate-based dimension reduction technique. The flexibility optimisation approach is demonstrated on the Orkney grid model, incorporating demand and wind farm generation data, as well as multi-year charging data from 106 EVs. Results indicate that, by building upon the existing habits of EV users, curtailment can be reduced by 99.5% during a typical summer week—the period when curtailment is most prevalent. This research demonstrates a foundational and transferable approach which is cognisant of social-techno-economic factors towards accelerating decarbonisation and tackling the stochastic challenges of new demand and generation patterns on local distribution networks.
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Authors: Benoit Couraud, Valentin Robu, Sonam Norbu, Merlinda Andoni, Yann Rozier, Si Chen, Erwin Franquet,
Pierre-Jean Barre, Satria Putra Kanugrahan, Benjamin Berthou, David Flynn
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In several European countries, regulatory frameworks now allow households to form energy communities and trade energy locally via local energy markets (LEMs). While multiple mechanisms exist to allocate locally produced energy among members, their fairness remains insufficiently understood—despite energy justice being a key concern for communities. This paper first provides a thorough description of the collective self-consumption (CSC) process in France, offering a real-world framework for researchers. We then review the main types of fairness relevant to LEMs and identify appropriate indicators for each, including a new scalable indicator to evaluate meritocratic fairness. Using simulations across 250 randomly generated residential communities of 20 households, we assess and compare fairness across different LEM distribution mechanisms. Results show that average financial savings reach 12% with 40% PV uptake. Among the four widely used LEM mechanisms assessed, glass-filling with prioritization yields the highest egalitarian and min-max fairness. Double auction and pro rata schemes promote meritocracy, while standard glass-filling offers a strong balance across fairness objectives.
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