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Renewable energy has become more popular since it is cost-effective and more efficient than conventional energy sources. Biomass-based renewable energy is primarily used in emerging economies to ensure environmental sustainability. This study examines the asymmetric correlation between biomass energy consumption and CO2 emissions in the top-10 biomass energy consumer countries (Brazil, Canada, Thailand, China, Italy, India, Germany, USA, UK, and Japan). A new approach "Quantile-onQuantile (QQ)" is employed by utilizing the data from 1991 to 2018. Biomass energy consumption, with the exception of Thailand, significantly mitigates CO2 emissions at various quantiles in selected countries. As a robustness check, we used the quantile regression test, whose findings are consistent with the outcomes from the quantile-on-quantile method. However, the degree of asymmetry in the biomass energy-CO2 nexus varies by country, necessitating extra attention and government vigilance when developing biomass energy and environmental policies.

© 2021 Elsevier LtdDespite extensive research to address the impact of environmental reforms under the Paris Climate Agreement, current literature has failed to provide sufficient insights into Regional Comprehensive Economic Partnership (RCEP) countries. To this end, the current study attempts to address the impact of the economic complexity on environmental quality in the presence of renewable energy consumption, financial development, urbanization and energy innovation in RCEP countries from 1990 to 2019. Our empirical estimates confirm a significant association between environmental quality, economic complexity index, renewable energy consumption, financial development, urbanization and energy innovation in the short-run and long run. Based on extensive econometric analysis (CS-ARDL, AMG, PMG, FMOLS, and DOLS), we conclude that economic complexity, renewable energy, and energy innovation effectively mitigate environmental degradation. At the same time, financial development and urbanization have an adverse impact on the environment. These findings have extensive policy implications for policymakers and environmental stakeholders, who are aiming to achieve sustainable energy policy and economic growth to meet the environmental commitments under Paris Climate Agreement.

Abstract Hydrothermal liquefaction (HTL) of biomass into biocrude is attractive but the biocrude themselves are poor fuels, which need to be upgraded for further utilization. Compared with the traditional catalytic upgradation process, a non-catalytic method for biocrude upgrading in the aqueous waste (HTL-AW) derived from HTL of cornstalk was proposed. Optimal reaction conditions of upgradation process were obtained at 356 °C (temperature), 37 min (reaction time) and 19 mL/g (HTL-AW/biocrude) based on the response surface methodology. The biocrude was effectively upgraded in the HTL-AW and a high hydrogen to carbon effective (H/Ceff) ratio of 1.07 with a higher heating value of 36.94 MJ/kg was observed. The energy recovery of ∼80% from biocrude to upgraded biocrude was feasible. GC–MS analysis showed that the contents of phenols and ketones were decreased from 65.61% to 48.38% and 22.39%–16.78%, respectively, while the contents of nitrogen-containing compounds n-hexadecanoic acid were increased from 2.25% to 10.15% and 9.56%–22.23%, respectively. The high H/Ceff was attributed to the promoted deoxygenation by alkali and alkaline earth metals as well as H+ enriched in the HTL-AW. This study demonstrates the feasibility of improving the H/Ceff of biocrude in the HTL-AW under a relatively mild reaction condition.

Abstract The sale of value-added byproducts from hydrogen-generating reactions is a strategic approach to lower the costs of hydrogen fuel in order to realize a truly sustainable hydrogen economy. Metal hydrolysis is a chemical process that produces hydrogen together with a metal hydroxide species; however, this reaction is rarely observed without chemical additives or extreme reaction conditions. Previously, we demonstrated that hierarchical nanoporous aluminum can create hydrogen at standard conditions for temperature and pressure via hydrolysis without any additives. The advantage of this method is the co-production of pure aluminum hydroxide (Al(OH)3). Here we explore the transformation of this Al(OH)3 hydrolysis byproduct into valuable materials to elucidate strategies in reducing the overall cost of hydrogen generated. In particular, we demonstrate in this work that (i) the synthesis of hierarchical nanoporous aluminum is scalable to meet the needs of large-scale production for a hydrogen economy, and (ii) the Al(OH)3 hydrolysis byproduct can be transformed to create high surface-area “activated alumina” (Al2O3) as a commercially viable product.

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 Anaerobic digestion of sludge is one of the most widely used processes for biogas and energy production. Conventionally, anaerobic digesters are operated at 35 °C to overcome the hydrolysis rate-limiting step. However, the energy expenditure for heating anaerobic digesters may be significant. The feasibility of operating anaerobic digesters at low mesophilic temperature (20 °C) by combining sludge ozonation was studied. Operation of three anaerobic reactors for 350 days showed that integrating solids ozonation and anaerobic digestion at 20 °C led to a higher volatile suspended solids (VSS) destruction of 60% than anaerobic digestion at 35 °C with raw sludge. Methane production in the reactor at 20 °C with sludge ozonation was enhanced from 62.6 mL CH 4 /g VSS in to 71.3 mL CH 4 /g VSS in for the 35 °C digester without sludge ozonation. Energy analysis showed that the 20 °C-ozonated digester produced 35% more energy than the 35 °C digester, with a net energy balance of +174 GJ/d and +129 GJ/d, respectively. The 20 °C-ozonated digester had a higher Energy Sustainability Index (ESI) (2.88) than the 35 °C digester (2.33) suggesting a more energetically sustainable option.

Abstract An active regenerative solar still with an area of 1.03 m 2 , enabling one to reuse the latent heat of condensation and sensible heat of brine, is constructed and tested indoors, using a solar simulator for irradiation. In this still, a considerable fraction of the latent and sensible heat is successfully recycled and utilized for preheating the feedstock and recycling air via a falling film evaporator–condenser. The forced thin layer evaporation and film condensation, which are the efficient enhanced processes for heat transfer, are applied in this unit. As a result, the performance ratio of the unit is about two to three times greater than that of a conventional basin-type solar still (single-effect).

Abstract A Cu/Ni composite electrode is proposed for increasing the anodic coulombic efficiency and electrode operation time in thermally regenerative ammonia batteries (TRABs) used for converting low-grade waste heat into electrical power. The performance of a TRAB employing a Cu/Ni composite electrode (TRAB-Cu/Ni) is comparably studied, and the effects of the electroplating conditions are investigated. In comparison to the TRAB-Cu system, TRAB-Cu/Ni achieves similar maximum power (6.5 mW), but increased anodic coulombic efficiency (94%) and a significantly extended electrode operation time (>55 h). During electroplating, the structure of the composite electrode is influenced by the electroplating time and the concentrations of HEDP and Cu2+ in the electroplating baths. Optimal electroplating conditions for achieving maximum power (electroplating time of 60 min, HEDP concentration of 0.48 M, and Cu2+ concentration of 0.06 M) are also identified.

Today, the use of renewable energies in buildings represents one of the main ways to reach a sustainable world. Whilst present buildings are still often energivorous systems, in the near future they will have to be converted to (or replaced by) zero energy buildings, also capable to export green energy (produced on-site by renewables) towards other buildings and/or users. This review article focuses on a selection of research papers, presented at the 16th International Conference on Building Simulation (BS 2019), regarding renewable energy applications, energy saving and comfort techniques for buildings. BS 2019 conference was organized in collaboration with the International Building Performance Simulation Association (IBPSA) and it was held at the Angelicum Congress Centre (San Tommaso d’Aquino Pontifex University) in Rome, Italy, during September 2-4, 2019. The conference was attended by 912 researchers and experts, with 660 presented research papers. The above-mentioned selection of papers is included in a dedicated Special Issue of the Renewable Energy - An International Journal (RENE), titled “Renewable energies: simulation tools and applications”. Reported studies are mostly dedicated to models, simulations, and optimization procedures of renewable energy devices. Specifically, photovoltaic systems, building integrated photovoltaic collectors, hybrid photovoltaic/thermal systems, solar thermal collectors as well as other energy efficiency tools are analysed through different simulation approaches and suitable optimization procedures. Attention is also paid to specific case studies related to innovative combinations of renewable energy devices and innovative envelope materials in different building typologies and weather zones. In some papers, solar energy is exploited for space heating and cooling purposes, while in other articles renewables or other energy tools are studied to achieve comfort targets, low grid dependencies, smart building/communities, and mainly the zero energy building goal.