Production & Supply Chain

Rural mini-grids in Ghana often experience substantial midday solar PV generation surpluses due to mismatches between peak production and local demand with excess energy (redundant energy) frequently curtailed once batteries are fully charged. This underutilisation limits the socio-economic benefits of renewable electrification and highlights the need for alternative long-duration storage solutions. This study investigated the technoeconomic feasibility of converting excess PV energy from a 54 kWp mini-grid in Aglakope Ghana into hydrogen via electrolysis storing it and reconverting it to electricity using fuel cells. Redundant energy generation was quantified using measured PV output and load consumption and validated using statistical error metrics (R2 = 0.955). Hydrogen production and recovery potential were modelled for different electrolyser technologies and system performance was evaluated using round-trip efficiency (RTE) levelized cost of hydrogen (LCOH) and levelized cost of storage (LCOS) with comparative analysis against additional battery capacity. The results yielded an average monthly excess energy of about 2250 kWh convertible into 43–53 kg per month of hydrogen depending on electrolyser type. The proposed hydrogen-fuel cell pathway yielded a RTE of 44.4 % LCOH of $4.97/kg and LCOS of $0.249/kWh which is about 13 % higher than lithium-ion storage benchmarks. The study findings demonstrate that hydrogen storage can complement batteries offer seasonal and multi-day storage capability and reduce renewable curtailment. Therefore wider adoption could be supported by cost reductions efficiency improvements and enabling policies positioning hydrogen-based storage as a viable pathway for resilient low-carbon rural electrification in off-grid contexts.

Hydrogen produced from renewable sources is crucial for decarbonizing hard-to-abate sectors and achieving netzero targets. This study examines hydrogen production through the novel thermo-catalytic reforming (TCR) process using agricultural and forestry residues. The research aims to develop and optimize regression models that integrate feedstock properties (ash hydrogen-to-carbon molar ratio and lignin) and process parameters (reactor and reformer temperatures) to predict yields of hydrogen (H2) syngas methane (CH4) and carbon dioxide (CO2). Three biomass feedstocks – softwood pellets (SWPs) hardwood pellets (HWPs) and wheat straw pellets (WSPs) – were analyzed at reactor temperatures of 400–550 ◦C and reformer temperatures of 500–700 ◦C. Predictive models for H2 (R2 = 0.9642 RMSE = 1.0639) and syngas (R2 = 0.9894 RMSE = 0.0140) yields show strong agreement and accuracy between the predicted and experimental values. In contrast the models for CH4 and CO2 yields show higher variability in the predictions. Reformer temperature was the most significant parameter influencing the yields of H2 and syngas. The optimal H2 yields predicted for the model were obtained for HWPs at 550/700 ◦C (26.67 g H2/kg dry biomass) followed by SWPs at 550/700 ◦C (24.11 g H2/kg dry biomass) and WSPs at 550/685.2 ◦C (18.78 g H2/kg dry biomass). The volumetric syngas yields were highest for HWPs at 550/700 ◦C (0.831 Nm3 /kg dry biomass) followed by SWPs (0.777 Nm3 /kg dry biomass) and WSPs (0.634 Nm3 /kg dry biomass). This study demonstrates that regression modelling accurately predicts H2 and syngas yields which would help to expand the applicability of TCR technology for large-scale hydrogen production contributing to the decarbonization of the energy sector.

Sunlight-driven water splitting allows renewable hydrogen to be produced from abundant and environmentally benign water. Large-scale societal implementation of this green fuel production technology within energy generation systems is essential for the establishment of sustainable future societies. Among various technologies photocatalytic water splitting using particulate semiconductors has attracted increasing attention as a method to produce large amounts of green fuels at low cost. The key to making this technology practical is the development of photocatalysts capable of splitting water with high solar-to-fuel energy conversion efficiency. Furthermore advances that enable the deployment of water-splitting photocatalysts over large areas are necessary as is the ability to recover hydrogen safely and efficiently from the produced oxyhydrogen gas. This lead article describes the key discoveries and recent research trends in photosynthesis using particulate semiconductors and photocatalyst sheets for overall water splitting via one-step excitation and two-step excitation (Z-scheme reactions) as well as for direct conversion of carbon dioxide into renewable fuels using water as an electron donor. We describe the latest advances in solar watersplitting and carbon dioxide reduction systems and pathways to improve their future performance together with challenges and solutions in their practical application and scalability including the fixation of particulate photocatalysts hydrogen recovery safety design of reactor systems and approaches to separately generate hydrogen and oxygen from water.

This study engineered seabed sediment with microwave-assisted Ni2+ -substitution to enhance its composition and properties. The catalytic activity of microwave-assisted Ni2+ - substituted seabed sediment (Mwx%Ni-SB) was investigated in the two-stage pyrolysis of plastic waste for hydrogen production. The characterization reveals microwave irradiation synergistically modifies the physical properties (increasing functional groups reducing crystallinity) and electronic properties (modulating bandgap energy increasing electron density) of the Mwx%Ni-SB thereby improving methane reforming performance. Microwave treatment compresses and rearranges Ni2+ ions within the sediment lattice resulting in increased order and density and creating defects that enhance catalytic activity. GC-TCD analysis demonstrates that the use of catalysts in the first and second stages more than doubled hydrogen production (109.74%) compared to not using catalysts. Therefore increased Ni2+ substitution significantly reduced methane production by 49.04% while simultaneously boosting hydrogen production by 23.00%.

Microbial electrolysis cells (MECs) have garnered significant attention as a promising solution for industrial wastewater treatment enabling the simultaneous degradation of organic compounds and biohydrogen production. Developing efficient and cost-effective cathodes to drive the hydrogen evolution reaction is central to the success of MECs as a sustainable technology. While numerous lab-scale experiments have been conducted to investigate different cathode materials the transition to pilot-scale applications remains limited leaving the actual performance of these scaled-up cathodes largely unknown. In this study nickel-foam and stainless-steel wool cathodes were employed as catalysts to critically assess hydrogen production in a 150 L MEC pilot plant treating sugar-based industrial wastewater. Continuous hydrogen production was achieved in the reactor for more than 80 days with a maximum COD removal efficiency of 40 %. Nickel-foam cathodes significantly enhanced hydrogen production and energy efficiency at non-limiting substrate concentration yielding the maximum hydrogen production ever reported at pilot-scale (19.07 ± 0.46 L H2 m− 2 d− 1 and 0.21 ± 0.01 m3 m− 3 d− 1 ). This is a 3.0-fold improve in hydrogen production compared to the previous stainless-steel wool cathode. On the other hand the higher price of Ni-foam compared to stainless-steel should also be considered which may constrain its use in real applications. By carefully analysing the energy balance of the system this study demonstrates that MECs have the potential to be net energy producers in addition to effectively oxidize organic matter in wastewater. While higher applied potentials led to increased energy requirements they also resulted in enhanced hydrogen production. For our system a conservative applied potential range from 0.9 to 1.0 V was found to be optimal. Finally the microbial community established on the anode was found to be a syntrophic consortium of exoelectrogenic and fermentative bacteria predominantly Geobacter and Bacteroides which appeared to be well-suited to transform complex organic matter into hydrogen.

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.

This study presents a scientometric analysis of renewable energy applications in low-temperature regions focusing on green hydrogen production carbon storage and emerging trends. Using bibliometric tools such as RStudio and VOSviewer the research evaluates publication trends from 1988 to 2024 revealing an exponential growth in renewable energy studies post-2021 driven by global policies promoting carbon neutrality. Life cycle assessment (LCA) plays a crucial role in evaluating the environmental impact of energy systems underscoring the need to integrate renewable sources for emission reduction. Hydrogen production via electrolysis has emerged as a key solution in decarbonizing hardto-abate sectors while carbon storage technologies such as bioenergy with carbon capture and storage (BECCS) are gaining traction. Government policies including carbon taxes fossil fuel phase-out strategies and renewable energy subsidies significantly shape the energy transition in cold regions by incentivizing low-carbon alternatives. Multi-objective optimization techniques leveraging artificial intelligence (AI) and machine learning are expected to enhance decision-making processes optimizing energy efficiency reliability and economic feasibility in renewable energy systems. Future research must address three critical challenges: (1) strengthening policy frameworks and financial incentives for largescale renewable energy deployment (2) advancing energy storage hydrogen production and hybrid energy systems and (3) integrating multi-objective optimization approaches to enhance cost-effectiveness and resilience in extreme climates. It is expected that the research will contribute to the field of knowledge regarding renewable energy applications in low-temperature regions.

In the introduction to this article a brief overview of the generated energy and the power produced by the photovoltaic systems with a peak power of 3 MWp and different tilt and orientation of the photovoltaic panels is given. The characteristics of the latest systems generating energy by wind turbines with a capacity of 3.45 MW are also presented. In the subsequent stages of the research the necessity of balancing the energy in power networks powered by a mix of renewable energy sources is demonstrated. Then a calculation algorithm is presented in the area of balancing the energy system powered by a photovoltaic–wind energy mix and feeding the low-emission hydrogen production process. It is analytically and graphically demonstrated that the process of balancing the entire system can be influenced by structural changes in the installation of the photovoltaic panels. It is proven that the tilt angle and orientation of the panels have a significant impact on the level of power generated by the photovoltaic system and thus on the energy mix in individual hourly intervals. Research has demonstrated that the implementation of planned design changes in the assembly of panels in a photovoltaic system allows for a reduction in the size of the energy storage system by more than 2 MWh. The authors apply actual measurement data from a specific geographical context i.e. from the Lublin region in Poland. The calculations use both traditional statistical methods and probabilistic analysis. Balancing the generated power and the energy produced for the entire month considered in hourly intervals throughout the day is the essence of the calculations made by the authors.

A pivotal ambition to aid global decarbonisation efforts is green electrolytic hydrogen produced with renewable energy. Prolonged operation of water electrolysers induces cell degradation decreasing production efficiency and gas yield over the lifespan of the electrolyser stack. Considerations for degradation modelling is seen to a varying extent in previous literature. This work shows the effects of including degradation modelling within existing system scenarios and new ones to demonstrate the impact of inclusion on key techno-economic parameters. A fundamental Anion Exchange Membrane electrolyser model is constructed validated and utilised into a broader hydrogen and oxygen co-production system powered by solar-PV. A second scenario tests the compatibility of the no-degradation trend with reference material and then investigates the effects of including degradation modelling showing only a 1.47% increase in levelised cost of hydrogen (LCOH). Subsequent scenarios include determining that byproduct oxygen utilisation becomes beneficial for a scenario with rated electrolyser power of above 35 MW and the observations related to stack replacement strategies are discussed. Under hypothetically higher degradation rates detriment to gas yield and LCOH is around 5% for average operational degradation rates of 15–20 μV/hr and around 10% for 30–40 μV/hr compared to around 2% for the model baseline average rate of 5.23–5.26 μV/hr.

The main aim of this study deals with the potential evaluation of a fluidized bed membrane reactor (FBMR) for hydrogen production as a clean fuel carrier via methanol steam reforming reaction comparing its performance with other reactors including packed bed membrane reactors (PBMR) fluidized bed reactors (FBR) and packed bed reactors (PBR). For this purpose a two-dimensional axisymmetric numerical model was developed using computational fluid dynamics (CFD) to simulate the reactor performances. Model accuracy was validated by comparing the simulation results for PBMR and PB with experimental data showing an accurate agreement within them. The model was then employed to examine the effects of key operating parameters including reaction temperature pressure steam-to-methanol molar ratio and gas volumetric space velocity on reactor performance in terms of methanol conversion hydrogen yield hydrogen recovery and selectivity. At 573 K 1 bar a feed molar ratio of 3/1 and a space velocity of 9000 h−1 the PBMR reached the best results in terms of methanol conversion hydrogen yield hydrogen recovery and hydrogen selectivity such as 67.6% 69.5% 14.9% and 97.1% respectively. On the other hand the FBMR demonstrated superior performance with respect to the latter reaching a methanol conversion of 98.3% hydrogen yield of 95.8% hydrogen recovery of 74.5% and hydrogen selectivity of 97.4%. These findings indicate that the FBMR offers significantly better performance than the other reactor types studied in this work making it a highly efficient method for hydrogen production through methanol steam reforming and a promising pathway for clean energy generation.