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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.

Abstract In recent years, many countries have been endeavoring to exploit the offshore wind energy in terms of overcoming the limitations of on-land wind energy. Considering that mountains cover 70 percent of the Korean Peninsula and arable plains for wind energy are negligibly small, Korean government aggressively drives the offshore wind development of the Korean Peninsula. In this context, KEPCO-RI (Korea Electric Power Corporation-Research Institute) has been performing a feasibility study for construction of the first offshore wind farm in Korea, including wind resource assessments around the Korean Peninsula. This paper provides a summary of the offshore wind resources of the Korean Peninsula, by analyzing marine buoy datasets measured at 5 positions over the period of 12 years, the QuikSCAT satellite data measured over 9 years, and a numerical wind map based on meteorological data measured for 4 years. Based on these datasets, wind resources are assessed, and economical efficiency is evaluated by means of the expected capacity factor. The analyzing results will be utilized to decide location of the first offshore wind farm in Korea.

This paper presents the cooling performance of a water-to-refrigerant type ground heat source heat pump system (GSHP) installed in a school building in Korea. The evaluation of the cooling performance has been conducted under the actual operation of GSHP system in the summer of year 2007. Ten heat pump units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. To analyze the cooling performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the cooling capacity and the input power were evaluated to determine the cooling performance of the GSHP system. The average cooling coefficient of performance (COP) and overall COP of the GSHP system were found to be ∼8.3 and ∼5.9 at 65% partial load condition, respectively. While the air source heat pump (ASHP) system, which has the same capacity with the GSHP system, was found to have the average COP of ∼3.9 and overall COP of ∼3.4, implying that the GSHP system is more efficient than the ASHP system due to its lower temperature of condenser.

© 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.

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 Renewable energy resource inventories show that ocean waves are one of the most energy dense untapped resources in the world, and present an opportunity to generate significant quantities of electricity. To accurately assess the levels of usable energy over long periods, a parametric representation of the raw wave resource is required. This study investigates the variability across four wave energy assessment methods, and two input data sources, to quantify the uncertainties in WEC power production assessments. Two conventional methods were tested: a time-series method and a standard spectral method with a generic spectral shape. Two higher fidelity techniques were additionally studied; an aggregate spectral and a partitioned spectral method. Annual WEC energy production assessments varied between 472 MWh and 543 MWh, a difference of 15%. The partitioned spectral method is shown to minimize prediction uncertainties, yet results in a 14% reduction in annual WEC energy production and increasing power variability. Spectral shape has limited impact on power estimates and energy production assessments, while the numerical wave model data can underestimate annual energy estimates by up to 13%. These uncertainties significantly impact the feasibility of wave energy developments and need to be accounted for as the industry matures.

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.