A detailed review of wave energy resource assessment and the state-of-the-art of deployed wave energy converters (WECs) in real environmental conditions in the Mediterranean Sea have been analysed in this study. The installed power of the several deployed WECs in the Mediterranean Sea varies between 3−2500 kW. Ten project cases of deployed WECs in the basin are presented, with their analysis of the essential features. Five different types of WEC have already been tested under real environmental conditions in Italy, Greece, Israel and Gibraltar, with Italy being the Mediterranean country with the most deployed WECs. The main questions of the relevant studies were the ongoing trends, the examination of WECs in combination with other renewable sources, the utilising of WECs for desalination, and the prospects of wave energy in the Mediterranean islands and ports. This paper is the first comprehensive study that overviews the recent significant developments in the wave energy sector in the... [more]

The aim of our study was to analyze whether the increase in the use of renewable energy can help GDP growth. The research carried out shows that renewable energy has the ability to decrease or neutralize the negative impact of greenhouse gases (GHG), but also to maintain economic growth. We focused our analysis on the EU-28 as we know that the EU Commission’s aim, in the near future, is to join forces to reduce the GHG used and move to renewable sources. We used a panel analysis with data between 2000 and 2019 from all Member States, and our results showed that their economic growth is influenced positively by the production of renewable energy, the GHG per capita, and the GHG intensity per GDP.

Buildings, energy, and the environment are key issues facing construction around the world. The energy efficiency of buildings is a key topic when it comes to reducing the world’s energy consumption, releasing harmful gases, and global climate change, as they consume about 40% of the world’s energy supplies. Heat losses in buildings reduce the energy performance of buildings and are basically important to them. In the paper, the authors focus on the main problems related to heat losses generated by chimney systems, which are inseparable equipment of building structures, resulting in lower energy efficiency and, at the same time, technical efficiency and durability of the building partitions themselves. Authors present thermal imaging with its contribution to the detection of heat losses, thermal bridges, insulation problems, and other performance disturbances, and then verifications using appropriate simulation models. The mathematical apparatus of artificial neural networks was implem... [more]

Costs to permit Marine Energy projects are poorly understood. In this paper we examine environmental compliance and permitting costs for 19 projects in the U.S., covering the last 2 decades. Guided discussions were conducted with developers over a 3-year period to obtain historical and ongoing project cost data relative to environmental studies (e.g., baseline or pre-project site characterization as well as post-installation effects monitoring), stakeholder outreach, and mitigation, as well as qualitative experience of the permitting process. Data are organized in categories of technology type, permitted capacity, pre- and post-installation, geographic location, and funding types. We also compare our findings with earlier logic models created for the Department of Energy (i.e., Reference Models). Environmental studies most commonly performed were for Fish and Fisheries, Noise, Marine Habitat/Benthic Studies and Marine Mammals. Studies for tidal projects were more expensive than those p... [more]

The solid scramjet has become one of the most promising engine types. In this paper, we report the first direct-connect test of a solid scramjet with symmetrical structure, carried out using boron-based fuel-rich solid propellant as fuel. During the test, which simulated a flight environment at Mach 5.6 and 25 km, the performance of the solid scramjet was obtained by measuring the pressure, thrust, and mass flow. The results show that, due to the change in the combustion area of the propellant and the deposition of the throat in the gas generator during the test, the equivalence ratio gradually increased from 0.54 to 0.63. In a solid scramjet, it is possible to obtain a symmetrical distribution of the flow field within the combustor. Moreover, in a multi-cavity combustor, the combustion state expands from the cavity to the center of the flow channel. The performance of the solid scramjet increased during the test, reaching a combustion efficiency of about 42%, a total pressure recovery... [more]

Battery storages are an essential element of the emerging smart grid. Compared to other distributed intelligent energy resources, batteries have the advantage of being able to rapidly react to events such as renewable generation fluctuations or grid disturbances. There is a lack of research on ways to profitably exploit this ability. Any solution needs to consider rapid electrical phenomena as well as the much slower dynamics of relevant electricity markets. Reinforcement learning is a branch of artificial intelligence that has shown promise in optimizing complex problems involving uncertainty. This article applies reinforcement learning to the problem of trading batteries. The problem involves two timescales, both of which are important for profitability. Firstly, trading the battery capacity must occur on the timescale of the chosen electricity markets. Secondly, the real-time operation of the battery must ensure that no financial penalties are incurred from failing to meet the techn... [more]

Condensation trails and contrail cirrus are currently responsible for the largest contribution to radiative forcing in the aviation sector, yet they have lifetimes of only a few hours. Their much shorter lifetimes when compared to long-lived greenhouse gases makes them ideal for the implementation of short-term mitigation measures. The use of Sustainable Aviation Fuel (SAF) instead of regular jet fuel has been associated to a reduction in soot particle emissions, leading to a decrease in initial ice crystal numbers in contrails, but also to a possible increase in contrail frequency and contrail ice mass due to higher water vapor emissions. A computational model was used to explore the influence of the variations of soot and water vapor emissions when using SAF and SAF blends in the formation of contrails, their ensuing optical depth, and their lifespan. An increase in frequency of contrails was found in cases where regular jet fuel emissions were close to threshold conditions. Reductio... [more]

Battery energy storage systems (BESS) are an essential component of renewable electricity infrastructure to resolve the intermittency in the availability of renewable resources. To keep the global temperature rise below 1.5 °C, renewable electricity and electrification of the majority of the sectors are a key proposition of the national and international policies and strategies. Thus, the role of BESS in achieving the climate impact mitigation target is significant. There is an unmet need for a detailed life cycle assessment (LCA) of BESS with lithium-ion batteries being the most promising one. This study conducts a rigorous and comprehensive LCA of lithium-ion batteries to demonstrate the life cycle environmental impact hotspots and ways to improve the hotspots for the sustainable development of BESS and thus, renewable electricity infrastructure. The whole system LCA of lithium-ion batteries shows a global warming potential (GWP) of 1.7, 6.7 and 8.1 kg CO2 eq kg−1 in change-oriented... [more]

Limiting CO2 emissions has been adopted as a contemporary challenge and introduced into numerous global and regional policies. The measures taken to reduce greenhouse gas emissions largely relate to the decarbonization of the economy. Changes in the Polish energy sector are a huge challenge because the energy mix is dominated by the energy derived from coal combustion. Decarbonizing the energy sector will require significant financial resources. Therefore, several questions arise: What is the social attitude to the planned changes? How do residents treat the issue of greenhouse gases? Do they perceive the relationship between energy production and the quality of the natural environment? What are their expectations regarding the transformation of the energy sector? The aim of this study was to identify the opinion of the inhabitants of southeastern Poland on changes in the energy sector and its impact on the quality of the natural environment. The study was conducted at the turn of 2020... [more]

Circular economy and renewable energy infrastructure such as offshore wind farms are often assumed to be developed in synergy as part of sustainable transitions. Offshore wind is among the preferred technologies for low-carbon energy. Deployment is forecast to accelerate over ten times faster than onshore wind between 2021 and 2025, while the first generation of offshore wind turbines is about to be decommissioned. However, the growing scale of offshore wind brings new sustainability challenges. Many of the challenges are circular economy-related, such as increasing resource exploitation and competition and underdeveloped end-of-use solutions for decommissioned components and materials. However, circular economy is not yet commonly and systematically applied to offshore wind. Circular economy is a whole system approach aiming to make better use of products, components and materials throughout their consecutive lifecycles. The purpose of this study is to enable the integration of a sust... [more]

In recent years, there have been several types of energy storage technologies adopted in many different areas, such as peak shaving, frequency regulation, and renewable stabilization applications. Moreover, technologies of high energy and power density are useful for load leveling, power smoothing for renewable energy systems (RESs), and peak shaving for demand management. Under these circumstances, an estimation technique for assessing environmental issues applied to electrical energy storage (EES) systems is essential in order to promote commercialization of EES systems. Therefore, this paper proposes an estimation method for CO2 emission in cases where EES systems are introduced and not introduced. It is essential to evaluate environmental issues in EES systems at operation stages of their life cycle and make an effective contribution to environmental improvement and reduce potential adverse environmental impacts. Thus, this paper deals with an evaluation method for CO2 emission bas... [more]

This study assesses the potential environmental impacts related to the energy valorization of agro-food industry waste thought the Life Cycle Assessment methodology (ISO 14040). The system examined consists of a real anaerobic digester coupled with a combined anaerobic digester and heat and power plant (AD-CHP) operating in Sicily. The analysis accounts for all the impacts occurring from the delivery of the biomass to the AD-CHP plant up to the electricity generation in the CHP. The main outcomes of the study include the eco-profile of the energy system providing electricity and the assessment of the contribution of each life cycle phase aimed at identifying the potential improvement area. The obtained results highlight that the direct emissions associated with the biogas combustion process in the CHP account for 66% of the impact on climate change, and feedstock transport contributes 64% to the impact on mineral, fossil fuels, and renewable depletion. The contribution to the impacts c... [more]

There are four main waste products produced during the harvesting and milling process of sugarcane: cane trash, molasses, bagasse and mill mud−boiler ash mixture. This study investigates the value proposition of different techniques currently not being adopted by the industry in the utilisation of these wastes. The study addresses the technical challenges and the environmental impact associated with these wastes and comes up with some recommendations based on the recent findings in the literature. All the biomass wastes such as bagasse, trash (tops) and trash (leaves) have shown great potential in generating higher revenue by converting them to renewable energy than burning them (wet or dry). However, the energy content in the products from all the utilisation methods is less than the energy content of the raw product. This study has found that the most profitable and challenging choice is producing ethanol or ethanol/biogas from these wastes. The authors recommend conducting more rese... [more]

Food choices are complex and highly variable, even over short periods, as they are influenced by numerous psychological, social, and cultural factors, in addition to biological and economic ones. Consumer choices are increasingly complex because of the growing quantity and variety of available food products, which also affects individuals’ environments. This paper is part of a larger study on health-related food choices, and it discusses how food choices affect the environment. To achieve the research goal, classes of respondents that are homogeneous in their food choices were identified. The authors used an algorithm to build classification trees and found that health status is determined by respondents’ age and food consumption habits. The paper demonstrates that understanding individual nutritional choices is a prerequisite for changing consumption habits and shaping healthy behavior, which is in line with the principle of sustainable development through sustainable consumption. The... [more]

Production of energy and chemicals from biomass resources has been regarded as one promising method to address the challenge of global warming. In this research, production of acrylic acid from fumaric acid, one of the biomass-derived building blocks, is proposed. CuO was employed as a solid oxidant, which showed excellent activity and selectivity for the production of acrylic acid, and water played an essential role in acting as not only a solvent but also a catalyst in this process. An optimum acrylic acid yield of 76.4% was successfully obtained after the reaction of fumaric acid with CuO at 300 °C for only 60 s.This research provides a green and highly efficient way to produce value-added chemicals from biomass-derived building blocks, and thus is promising for practical application.

Safety is a critical feature for all passenger vehicles, making fail−safe operation of the traction drive system highly important. Increasing demands for traction drives that can operate in challenging environments over wide constant power speed ranges expose permanent magnet (PM) machines to conditions that can cause irreversible demagnetization of rotor magnets. In this paper, a comprehensive analysis of the demagnetization vulnerability in PM machines for an electric vehicle (EV) application is presented. The first half of the paper presents rotor demagnetization characteristics of several different PM machines to investigate the impact of different design configurations on demagnetization and to identify promising machine geometries that have higher demagnetization resistance. Experimental verification results of rotor demagnetization in an interior PM (IPM) machine are presented in the latter half of the paper. The experimental tests were carried out on a specially designed locked... [more]

The paper evaluates the rural development (RD) contribution of local economic activities (LEAs), whether generated or affected by the proximity of renewable energy plants (REPs). The study also informs about LEAs’ role as co-players in the fight against climate change. Semi-structured research interviews have been applied to identify LEAs’ BM (business model) in Andalusia, Murcia, and Catalonia, autonomous communities of Spain. Most LEAs present a BM based on the RE plant, and others do not, but they still contribute to RD, rural communities’ well-being and global sustainability. Results show, first, that certain LEAs, due to their inter-connection with large REPs, can innovate and create a significant number of stable jobs. Second, land leasing to REPs allows for temporary farms’ diversification, which is conditioned to its bargaining power. Third, advice on integration RE projects in RD strategies should be provided. Conclusions suggest the need for new governance to favor energy tra... [more]

Industrial human activity has led to the release of substantial amounts of heavy metals into the environment. Contamination of water with heavy metals such as lead, cadmium, copper, zinc, chromium, or nickel represents a serious problem. As part of the circular economy, it is appropriate to use biowaste from agriculture, fisheries, and the timber industry as biosorbents. In this literature review, the potential of using these biowaste groups as biosorbents for metal removal is presented. This biowaste is characterized by the presence of carboxyl, hydroxyl, carbonyl, amide, amine, sulfydryl, and other groups on their surface, which form complexes and chelates with metals present in water. Biosorption seems to be a potential alternative to conventional technologies for removing or recovering heavy metals from water or wastewater, which are uneconomical and generate additional waste. The paper demonstrates that harnessing the potential of biowaste to remove metals is beneficial to the env... [more]

The objective of this study was to investigate the factors that influence the consumer adoption of renewable energy in Thailand. The study adopted an extended theory of planned behavior (TPB) by including three additional variables. The study applied a quantitative study methodology, with primary data collected using a survey of consumers in five major cities in Thailand. The data were analyzed using structural equation modeling (SEM). The findings of the study indicated that perception of self-effectiveness, environmental concern, renewable energy awareness, and beliefs about renewable energy benefits have a significant and positive effect on consumers’ intention to adopt renewable energy. The cost of renewable was found to have a negative but non-significant influence on consumers’ adoption of renewable energy, while risk/trust perception was found to have a positive but non-significant influence on consumers’ adoption of renewable energy. The study concluded that stakeholders should... [more]

A number of empirical correlations have been achieved between the hydraulic properties measured through geoelectrical methods and water well data of Arak Aquifer located in Markazi province, Iran. The geoelectrical method of Vertical Electrical Sounding (VES) technique was used to calculate the hydraulic properties of the aquifer. Through the VES technique, the pivotal hydraulic properties such as porosity, hydraulic conductivity, and specific yield of the layers were calculated. The results of VES technique were compared with the data obtained from seven observation water wells that were already drilled as exploratory coring boreholes in the region. The results demonstrate that as the porosity and hydraulic conductivity of the water-bearing layer increase, the results of VES technique appear much identical to the water well records. Furthermore, the specific yield was calculated as 4.6% that was very close to the value of 3.5% measured through the previous pumping tests. Moreover, VES... [more]

During the last decade, the application of pretreatment has been investigated to enhance methane production from lignocellulosic biomass such as wheat straw (WS). Nonetheless, most of these studies were conducted in laboratory batch tests, potentially hiding instability problems or inhibition, which may fail in truly predicting full-scale reactor performance. For this purpose, the effect of an alkaline pretreatment on process performance and methane yields from WS (0.10 g NaOH g−1 WS at 90 °C for 1 h) co-digested with fresh wastewater sludge was evaluated in a pilot-scale reactor (20 L). Results showed that alkaline pretreatment resulted in better delignification (44%) and hemicellulose solubilization (62%) compared to untreated WS. Pilot-scale study showed that the alkaline pretreatment improved the methane production (261 ± 3 Nm3 CH4 t−1 VS) compared to untreated WS (201 ± 6 Nm3 CH4 t−1 VS). Stable process without any inhibition was observed and a high alkalinity was maintained in th... [more]

The built environment is the global sector with the greatest energy use and greenhouse gas emissions. As a result, building energy savings can make a major contribution to tackling the current energy and climate change crises. Fluid dynamics models have long supported the understanding and optimization of building energy systems and have been responsible for many important technological breakthroughs. As Covid-19 is continuing to spread around the world, fluid dynamics models are proving to be more essential than ever for exploring airborne transmission of the coronavirus indoors in order to develop energy-efficient and healthy ventilation actions against Covid-19 risks. The purpose of this paper is to review the most important and influential fluid dynamics models that have contributed to improving building energy efficiency. A detailed, yet understandable description of each model’s background, physical setup, and equations is provided. The main ingredients, theoretical interpretatio... [more]

In this study, a collaborative simulation method is proposed to predict dynamic variations of the thermal environment in an air-conditioned room. The room thermal environment was predicted and analyzed by varying the structural and control parameters of the air conditioner considering the dynamic coupling effect. Connections and regularities were established between the applicable parameters and evaluation indices of the thermal environment. The simulation results demonstrated the interactions among the system structural parameters, control parameters, and the thermal environment. Within a certain parameter range, the evaporator structure exhibited a significant effect on temperature uniformity and vertical air temperature difference, followed by predicted mean vote (PMV) and draught rate (DR). The associated evaluation indices were sensitive to fin spacing, tube spacing, and tube outer diameter, in the same order, which were structural parameters of the evaporator. The effect of the a... [more]

Crop-based biogas energy production, in combination with electricity generation under subsidy schemes, is no longer considered a favourable business model for biogas plants. Switching to low-cost or gate fee feedstocks and utilising biogas via alternative pathways could contribute to making existing plants fit for future operations and could open up new space for further expansion of the biogas sector. The aim of this study was to combine a holistic and interdisciplinary approach for both the biogas production side and the utilisation side to evaluate the impact of integrating the biogas sector with waste management systems and energy systems operating with a high share of renewable energy sources. The geospatial availability of residue materials from agriculture, industry and municipalities was assessed using QGIS software for the case of Northern Croatia with the goal of replacing maize silage in the operation of existing biogas plants. Furthermore, the analysis included positioning... [more]

Modernisation of municipal and industrial wastewater treatment plants (WWTPs) should be carried out, taking into account its impact on global warming, e.g., through carbon footprint (CF) analysis. An important industrial sector in Poland is the dairy industry. In dairy WWTPs, the aerobic sewage sludge stabilisation applied thus far is being replaced by the anaerobic process. This change is positive due to the possibility of energy production, but it is unclear how it affects greenhouse gases (GHG) emissions. The aim of the research was to perform CF analysis for two scenarios of dairy WWTP operation. The analysis was based on the real operating data of the current system (current scenario) and project of its modernisation (alternative scenario). The current scenario consists of mechanical and dissolved air flotation (DAF) treatment, biological treatment in sequence batch reactors (SBRs), aerobic sewage sludge stabilisation and its final farmland usage. The alternative scenario assumes... [more]