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This study aims to measure the relationship between technological progress, renewable energy, and green economic growth (GEG). This study uses a data envelopment analysis (DEA) estimation method to evaluate the association between government expenditure on research and development (R&D), renewable energy deployment, and GEG in the Economic Community of West African States (ECOWAS) between 1990 and 2018. The estimates revealed an inconsistent GEG indicator in the analysis, suggesting the lesser impact disposition of public policy. In addition, the energy efficiency ratio of ECOWAS subregion is under 0.50, implying energy poverty in the sub-region. Many people do not have sufficient energy to heat and cool their homes to enough temperature and meet their basic needs and energy security concerns. This research discovered that a percentage growth increase in renewable energy deployment results in a 3.2% increase in growth in sustainable performance. Alongside an essential effect of one percentage point growth in R&D expenditure boosts economic system sustainable performance to 4.4% combined with a supported effect of one percent. This research reveals that the ECOWAS government expenditure on human resources and R&D of sustainable energy resources would result in a low carbon growth via an advanced technological production process; nevertheless, the impacts are varied in the various countries in ECOWAS. (c) 2022 Elsevier Ltd. All rights reserved.

Abstract Electrocatalytic CO2 reduction (ECO2R) is an environment-friendly way to convert CO2 into profitable products. Amine solution recently has been employed as an electrolyte in ECO2R but suffers from low efficiency. Herein, aqueous solutions containing different amine-based deep eutectic solvents (DESs) were used as electrolytes for CO2 reduction. The effect of different DESs on the CO2 reduction was investigated at Ag, Cu, and Zn metal electrodes. Tafel and electrochemical impedance spectroscopy (EIS) were applied to understand the CO2 reduction. DES in aqueous solution facilitates the CO2 reduction to CO with higher faradaic efficiency of CO (FECO) than amine solutions and a mixture of hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). Both HBD and HBA have an influence on CO2 reduction. [Monoethanolamine hydrochloride] [methyldiethanolamine] ([MEAHCl][MDEA]) gives high FECO, 71% FECO at −1.1 V vs RHE at Ag electrode, 33% higher than [MEAHCl][MEA]. Experimental results and EIS analysis reveal that the facilitation of CO2 reduction to CO probably stems from a synergistic effect of nano-size agglomerate dispersion on Ag-surface, bicarbonate formation, exchange current density, and Cl− ions present in DESs. These findings present a feasible method to employ the aqueous MDEA-based DES solution as an electrolyte for CO2 reduction.

Due to the growing proportion of wind energy in Great Britain’s energy mix, prolonged periods of low wind power generation have become a significant challenge for decarbonising the electricity system. As such, characterising drought severity and duration is important for ensuring the reliability of the electricity system. Employing concepts derived from hydrology, an extreme value analysis was carried out on wind drought events in Great Britain based on 72 years of ERA5 reanalysis data. The application of pooling procedures was found to be beneficial in robustly identifying wind droughts in cases where the capacity factor is not constantly below an arbitrary threshold. The sequent peak algorithm pooling was found to have particular relevance for electricity systems where energy storage technologies are used to compensate for low wind power generation. The Pearson-III distribution was identified as a suitable model to represent extreme wind droughts, while the Lognormal and Generalised Pareto distributions are also viable alternatives. Sustained periods of low wind power generation with a duration of 14 days were estimated to have a return period of five years and the longest event on record of approximately 26 days is expected to occur once every 100 years. The investigation of these wind droughts from a hydrological perspective has thus shown that they may not be particularly rare occurrences.

Polycrystalline CuWO4 film is an emerging photoanode material for photoelectrochemical (PEC) water splitting with a small bandgap to absorb visible light and excellent stability in a neutral electrolyte. However, its PEC performance is quite low mainly due to its poor charge transfer characteristics. To enhance the performance of the CuWO4 photoanode, two modification strategies are employed; SnO2 as an electron transfer layer to improve the bulk charge separation efficiency of CuWO4 and cobalt phosphate as a co-catalyst to augment the surface charge separation efficiency at the interface of CuWO4||electrolyte. The two modifications enhance the PEC activity two times to 0.13 mA/cm2 @ 1.23 VRHE for water oxidation and 0.24 mA/cm2 @ 1.23 VRHE for hole scavenger oxidation, and exhibit an excellent stability in a neutral electrolyte. Although the performance is still very low compared to well-developed metal oxide photoanodes, this work shows possibility of further improvement with further developments of synthesis method as well as applying other elaborate modification strategies.

The catalytic steam reforming of the major biomass tar component, toluene, was studied over two commercial Ni-based catalysts and two prepared Ru–Mn-promoted Ni-base catalysts, in the temperatures range 673–1073 K. Generally, the conversion of toluene and the H2 content in the product gas increased with temperature. A H2-rich gas was generated by the steam reforming of toluene, and the CO and CO2 contents in the product gas were reduced by the reverse Boudouard reaction. A naphtha-reforming catalyst (46-5Q) exhibited better performance in the steam reforming of toluene at temperatures over 873 K than a methane-reforming catalyst (Reformax 330). Ni/Ru–Mn/Al2O3 catalysts showed high toluene reforming performance at temperatures over 873 K. The results indicate that the observed high stability and coking resistance may be attributed to the promotional effects of Mn on the Ni/Ru–Mn/Al2O3 catalyst.

Although design of offshore wind turbines has many similarities to that of onshore turbines, a lot of considerations should be made for the additional substructure imposed on hydrodynamic loads. The additional substructure prolongs the total tower length, increasing the tower bending moment and lowering the natural bending frequencies of the tower. Accordingly, system dynamic analyses associated with hydrodynamic load should be performed in the frequency domain in order to avoid bending modes of tower from the operation frequency ranges. In this paper, a method to generate hydrodynamic load for a finite element analysis is introduced, considering the characteristics of sea conditions for a candidate site of demonstration offshore wind farm in the west sea of Korea. In addition, a wind energy conversion system with a monopile foundation is fully modeled using the finite element method to simulate the various conditions based on IEC standard. Based on the FEM analyses of tower bending modes, optimal dimensions of the monopile for the candidate site are proposed.

Abstract A photovoltaic (PV) power conditioning system (PCS) must have high conversion efficiency and low cost. Generally, a PV PCS uses either a single string converter or a multilevel module integrated converter (MIC). Each of these approaches has both advantages and disadvantages. For a high conversion efficiency and low cost PV module, a series connection of a module integrated DC–DC converter output with a photovoltaic panel was proposed. The output voltage of the PV panel is connected to the output capacitor of the fly-back converter. Thus, the converter output voltage is added to the output voltage of the PV panel. The isolated DC–DC converter generates only the difference voltage between the PV panel voltage and the required total output voltage. This method reduces the power level of the DC–DC converter and enhances energy conversion efficiency compared with a conventional DC–DC converter.

Abstract This study was designed to investigate the role of political stability in the nexus between financial development, renewable energy, total reserves, agriculture value addition, and economic growth from 1995 to 2017 in 100 countries. The long-run causality was confirmed for GDP in politically free countries, which implies that political stability is beneficial for the economy. The GDP had bi-directional causality with financial development and total reserves. The increase in GDP was 0.199% (free countries), 0.097% (partly free countries), and 0.055% (not free countries) for 1% rise in financial development. The renewable energy-led growth hypothesis was confirmed in politically free and partly free countries. The impact of total reserves and renewable energy on GDP was insignificant in politically not free countries. The increase in GDP was 0.024% (free countries) and 0.106% (partly free countries) for 1% rise in total reserves. The economic advantage of agriculture value addition was more in politically not free countries (0.461%) followed by partly free and free countries. The agriculture value addition is required to stimulate the economy and ensure food availability.