Abstract

Renewable energy communities occupy a critical position in catalysing the energy transition within urban areas, while simultaneously making substantial contributions towards the realization of the Sustainable Development Goals outlined in the 2030 Agenda for Sustainable Development, adopted by all United Nations Member States in 2015. Positive Energy Districts are also gaining momentum, emerging as a concept of growing interest among researchers and urban planners. Renewable energy communities and positive energy districts are both expressions of sustainable urban energy forms, still there is the need to evaluate if a renewable energy community could be considered a positive energy district and under which conditions this transition will occur. To this scope, a holistic framework examining the transition from existing renewable energy communities to positive energy districts is proposed and characterized by focused and indicators, serving as critical instruments to conduct a tailored evaluation and characterization. Results demonstrate that the transition can be achieved by increasing by 20 % the renewable energy installations in the area.

Abstract

This study examines the utilization of process optimization as a viable strategy for addressing the issue of global warming through the conversion of carbon dioxide into methanol. In the realm of computational chemistry, the response surface methodology approach has evolved as an alternative for optimizing the reaction parameters through the utilization of statistical models. In the present study, promoted copper/zinc oxide/alumina catalyst was used for carbon dioxide conversion to methanol. The primary objective of the study was to enhance the overall methanol yield by optimizing the various factors in the methanol synthesis. This was accomplished by employing a combination of response surface methodology and one factor at a time techniques. The creation of statistical models was used to optimize the essential factors, and subsequently, one factor at a time. This helps in determining the optimum pressure, temperature, and hydrogen/carbon dioxide molar ratio. Impregnation technique was employed for the synthesis of promoted copper/zinc oxide/alumina catalyst. The analysis of variance results suggested the reduced quadratic model for carbon dioxide conversion, methanol selectivity and methanol yield as responses. The optimum process operating conditions were found to be the hydrogen/carbon dioxide ratio of 10, temperature of 300°C, pressure of 31 bar and gas hourly space velocity of 2160 mL/g.h, in which 28.6% carbon dioxide conversion, 59.2% methanol selectivity and 16.4% methanol yield were achieved. The catalytic performance was then investigated for high pressure range of 40 – 80 bar with other conditions were fixed at optimal value. The carbon dioxide conversion and methanol selectivity were found to increase with increasing pressure. The highest catalytic performance was achieved at 80 bar with carbon dioxide conversion of 68.35%, methanol selectivity of 93%, and methanol yield of 63.57%.

Abstract

Addressing the potential health benefits of climate change mitigation action, this study uses the Carbon Reduction Benefits on Health tool and the MARket ALlocation model to evaluate the health co-benefits of the proposed energy sector policies and measures in North Macedonia’s enhanced nationally determined contribution. The study hypothesises that implementing these policies and measures will significantly reduce morbidity and mortality due to air pollution by 2030. The results indicate 629 prevented bronchitis cases, 2,788 fewer asthma symptom days among children, and 143 preventable deaths, leading to considerable welfare improvements and economic savings. The findings underscore the importance of considering health outcomes in climate policy decisions, emphasising the substantial public health benefits alongside climate gains, as an incentive for emissions reduction. Sharing these findings with other countries will enhance efforts to limit the global temperature rise well below 2˚C by the century’s end.

Abstract

The long-term evolution of wind resources under climate change is investigated and discussed in the two largest markets of the Western world: Europe and North America. Wind speed projections from the Coupled Model Intercomparison Project 6 are employed considering the Shared Socioeconomic Pathways, the most up-to-date and elaborate climate scenarios proposed by the Intergovernmental Panel on Climate Change – specifically, a middle-of-the-road scenario and an augmented emissions scenario. In Europe, projections indicate a widespread, substantial decline in wind resources (~15% in wind power density). Whereas an overall decrease in wind energy is also anticipated in North America, this appears to be highly concentrated in different foci. Additionally, the evolution of wind resources in this continent is projected to be notably season-dependent, with strong increases of over 60% and decreases of up to 50%. Conversely, the evolution in Europe shows changes of lesser magnitude but more constant throughout the year. 

Abstract

Following evolving electricity markets, Transmission System Operators face challenges in processes of Net Transfer Capacity calculations. Increasing uncertainties stemming from growing electricity trade exchanges, make traditional monthly calculations obsolete. To enhance system stability, the paper proposes an implementation of a fast capacity calculation method aligned with day-ahead market principles. The study discusses capacity calculation regions aligning with European Legislation, particularly examining the Albanian Power System as a case study and introduces an improved approach to net transfer capacity calculations. The paper proposes and implements a Python algorithm to automate the net transfer capacity calculation process, obtaining improved efficiency in the calculation process. The paper emphasizes the importance of in ensuring power system security, promoting cross-border trade, and easing market developments, offering a practical solution to the problem of net transfer capacity calculation.

Abstract

Shared stand-up e-scooters have been used in Sweden since 2018. Both models in use and policies applied in different cities have evolved rapidly. The objective of this study was to examine the environmental impacts of shared stand-up e-scooters in use in Sweden; and to identify the key factors that impact the resource and energy efficiency of these e-scooters. The findings can help e-scooter providers and cities reduce the environmental impacts of shared e-scooter services. A comparative life cycle assessment was conducted on two main cases: Case 1 corresponds to first-generation shared e-scooter models that dominated the Swedish market from 2018 to 2020, while Case 2 corresponds to a significantly heavier e-scooter model that was introduced in Sweden from 2020 onwards. The results show that the production of e-scooters is the part of the life cycle with the largest contribution to the environmental impacts for both e-scooter models.

Abstract

Different effects of extreme hydrological events are evident in the physical and chemical water characteristics. Such events can cause water supply interruptions in rural areas, as is the case in Vlasotince, south-eastern Serbia. Therefore, this paper examines the values of selected parameters such as ammonia, nitrates, nitrites, turbidity, chemical oxygen demand calculated from the amount of potassium permanganate, iron, manganese, temperature, pH value, colour, and aluminium at the measuring point of Vlasotince to identify changes in raw water quality parameters during extreme hydrological events. Over a five-year period, fluctuations in water flow in the Vlasina River basin are considered. The interdependence between water flow and raw water quality parameters is assessed using a one-way analysis of variance and a post hoc Tukey Honestly Significant Difference test. Results reveal substantial differences in turbidity, chemical oxygen demand, nitrates, temperature, iron, colour, and manganese. Ammonia, nitrites, pH value, and aluminium exhibit no significant differences based on water flow intensity. The identification and quantification of risk factors affecting water supply during extreme hydrological events allow for a more appropriate response to given challenges and the organization of work in rural water supply systems. 

Abstract

The transition to renewable energy is hindered by the level of acceptance in society. The role of education in schools is crucial, and while numerous studies have been conducted, there is still a lack of exploration into the depth of the materials. This research was carried out to assess the readability level of material on renewable energy from geothermal resources in Vocational High School textbooks. The descriptive quantitative method was used, conducted in 19 Vocational High School with a study program in Technology and Engineering in Surakarta. The sample size was 340 respondents. Data were collected from textbooks and questionnaire results. The Gunning Fog Index scores indicated the material had low readability level with scores of 20, 18, and 21 for texts 1, 2, and 3. Text 1 is taken from book titled 'Energy Conversion Machines', Text 2 from 'Sustainable Energy Saving through Building', and Text 3 from 'Basic Knowledge of Mechanical Engineering. Additionally, the responses of readers indicated that more than 50% of respondents could easily comprehend the content in texts 2 and 3. Resulting, for text 1, over 50% of respondents reported understanding the content with some difficulty. These three books are also commonly used, making this research a valuable recommendation for stakeholders in curriculum design and educational planning.

Abstract

Multirotors have proven their significance in fields like aerial imaging, surveying, and inspection. However, their effectiveness is hindered by limited flight autonomy due to the low energy density of standard lithium polymer batteries and high power demand. This necessitates frequent recharging, limiting prolonged operational capabilities. In response, our study introduces a methodology to assess the feasibility of a hybrid internal combustion engine and electric generator set as an alternative power source for multirotors. We investigate three theoretical multirotor designs tailored for mid-to-heavy load capacities (15 – 35 kg max take-off mass) and evaluate both pure battery and hybrid power as vehicle energy sources. Our findings indicate that hybrid power significantly enhances endurance, enabling extended flight times and wider range coverage. This extended aerial presence achieved with the hybrid system's superior endurance over traditional batteries significantly enhances multirotor capabilities, enabling innovative applications and expanded use cases.

Abstract

Owing to the effect of temperature on the maximum power point of photovoltaic modules, the anticipated benefits of maximum power point tracking (MPPT) charge controller are also greatly affected under high-temperature environments. This paper presents experimental study results based on the investigations of the effect of high cell temperatures on the performance of MPPT charge controllers. The study was carried out over three months at Kenyatta University in Nairobi, Kenya under moderate and high temperature conditions. The experiments are carried out using two market-ready MPPT charge controllers and a normal pulse-width modulation (PWM) charge controller as the reference. The study establishes that below 50 °C, the MPPT charge controller exhibits significant advantages over its counterpart with about 24% - 29%, additional energy gain. However, at high cell temperatures, the MPPT charge controller loses its added advantage over the PWM charge controller and its performance benefits drop from an average of 28% to 0.2%. This demonstrates that an ordinary PWM charge controller would achieve the same yields under high-temperature conditions and at an even lower premium.

Abstract

Grasslands are characterized by native non-forest vegetation, occupying a large land area worldwide. The study was conducted in the Andean National Sanctuary of Ampay, Peru, 3,500-4,500 masl. The purpose has been to evaluate the relationship between biomass, forage productive potential, degree of soil erosion, presence of valuable species for grazing. The three-step (Parker) method was used for natural pastures and the linear intercept for vegetation. From thirteen zones, distributed in three study areas (Yanacocha, Uspacocha, Faccha), herbaceous vegetation frequency results were obtained. The grazing carrying capacity was 1.2 animal units/ha/year. The most productive area with species desirable for livestock was Uspacocha, which had better soil conditions without overgrazing, while the least productive was Yanacocha. The predominant families in herbaceous plant associations were Rosaceae, Poaceae, Asteraceae; the study area was in regular conservation condition with few eroded areas. At present, the inhabitants of the communities surrounding the study area use many of the plant species for feeding, medicinal, fuel, fodder, and manufacturing purposes; being necessary to promote self-sustainable development by strengthening production units.

Abstract

In contemporary urban contexts, addressing challenges like urban sprawl, pollution, and heat islands is imperative. Understanding urban mechanisms and prioritizing proximity and sustainable mobility are crucial for meeting citizens' needs. This study presents a quantitative model with 21 composite indicators, aligning with the 15-minute city theory's dimensions (EDU, HSW, L&C, SUP), to measure resource accessibility. Focused on Valencia, the analysis of its 70 neighborhoods reveals significant disparities in indicators, mainly due to geographical distribution. Peripheries consistently score lower, while city centers and high-status neighborhoods demonstrate higher values. This underscores the importance of targeted interventions to promote equitable access to resources across urban areas.

Abstract

Submetering with mobile measurement technology offers substantial benefits for energy system analysis in small and medium-sized enterprises. However, the effective and systematic analysis of submetering datasets is challenging due to the lack of a standardized concept and the limited measurement period. Based on empirically collected submetering data from selected case studies, this study investigates which data analyses are relevant for a systematic data analysis approach. In addition, key indicators and limitations of these analyses are examined and discussed. The results indicate that the use of standardized data analyses contributes to a more efficient and targeted energy system analysis. By applying various disaggregation analyses (e.g. base load disaggregation) and load profile characterization to the datasets, relevant electrical consumers and inefficiencies can be identified. The developed standardized data analyses address the initial step of analysis, which is “detection”. Limitations of standardized data analyses point to the need for individual detailed analyses that cover “diagnosis” and “optimization” as further steps of analysis. In conclusion, the results provide a first approach towards a standardized data analysis for short-term measurements.

Abstract

Implementing Circular Economy principles in the built environment is of utmost importance to reduce raw material extraction and generated waste. A transition is essential, especially as it is responsible for about 40% - 60% of global raw material extraction and 33% of total waste in the European Union. This paper shows the methodological approach to generate a digital Building model to enable Circular Economy in the early design stage, by coupling Generative Design methods, enabling automated variant generation of Digital building models, to Building Information Modelling-objects, and assessment-algorithms to evaluate the environmental impact and circularity. By visualizing the assessments of the generated variants of (so-called) Circular Twins in a Virtual Reality environment, including user interaction with a voice-controlled virtual Agent, the digital Circular Twin ecosystem enables the early implementation of the goals of the circular economy and sustainability in Architecture, Engineering and Construction.

Abstract

The term Industry 4.0 has been coined in Germany in 2011 and since then, it has officially started the so-called fourth industrial revolution. In the herein presented review, the industrial digitalization process of Italy is explored and cross-compared to the German one, in order to unearth and analyze the intrinsic systemic key-elements, which are responsible for the differentiated digital industrial development among the examined countries. As evidenced by the analytical study, which also entails the results of a survey conducted over 238 companies in Italy, the main responsible factor for the industrial digital gap among the countries seems to be represented by a digital holistic-based approach across the entire value chain of the product. This finding, besides being reflected into the very different nature of the two Industry 4.0 policy frameworks, is also supported by survey data, since the majority of the investigated performed interventions can mainly be applied to the production process, rather than to other crucial steps of the value chain. In this regard, the survey analysis suggests also that a lack of perception of the beneficial potential effect of the change of “digital paradigm” from the production process to the product itself is yet lacking within the Italian industrial mindset. Finally, the survey results support the widely discussed synergistic beneficial effect among ecology and digitalization. Indeed, the majority of the interviewed companies have reported that many of the carried-out digitalization measures have positively affected the energetic and sustainability-related dimensions.

Abstract

The use of renewable energy-generated hydrogen can be an effective solution to reduce the impact of carbon emissions on global climate change. Water electrolysis is a crucial technology for producing green hydrogen due to its scalability, which can help balance the gap between energy demand and supply. This study evaluates the technical feasibility of integrating an additional electrolysis component into a stand-alone community wind energy system. The wind power generated by the system charges a battery bank used for community business activities. The results showed significant excess energy that can be used to produce hydrogen. By integrating a 7 kW electrolyser, annual hydrogen production of up to 235 kg can be achieved without compromising the electrical load demand. Hydrogen can be used as a clean fuel to meet the usual unmet loads in off-grid systems like cooking, without requiring system upsizing.

Abstract

This paper presents an innovative, original approach to co-design retention ponds and floating photo voltaic solar plants as a water-energy nexus approach to reduce flooding and energy burden for one location. Case-study analysis was conducted in Waimanalo, Hawai’i. A flood model—from a previous study—was used provide a potential location for a retention pond and floating solar photovoltaic panels. This study found the co-design of retention ponds and floating PV solar can not only reduce future stormwater runoff by up to 50% but provide a total of 50% of onsite solar energy at a neighbourhood scale, demonstrating how clean energy and green infrastructure can help advance environmental and social justice. Several takeaways from this study were taken into account and things to consider for a follow-up paper. One of the major challenges was finding a potential suitable location. Overcoming this challenge required using Google Maps and the flood model to pinpoint high flood accumulation and searching for a large green space that is in close vicinity to a developed neighbourhood. 

Abstract

Hydrogen will be a very important energy carrier in the near future. Nowadays, well over 95% of hydrogen is “grey”, i.e. obtained from fossil fuels with accompanying high CO₂ emissions. The objective should be to produce hydrogen in a sustainable way, without emitting additional CO₂ into the atmosphere. For a vast amount of required hydrogen, the technology openness is very important in order to produce “green” hydrogen as fast as possible in large quantities at low cost. Consequently, biomass has to be considered as a very important source of such hydrogen.

A very effective process for hydrogen generation based on allotherm steam reforming using energy from biomass is developed and tested in a pilot facility. Excess chemical energy from the process is used to generate steam and superheat it up to 1,200°C or even higher. Steam is the gasification and oxidation agent, energy carrier for the process and supplier of hydrogen molecules, as it reacts with biochar at the bottom of the reactor. Produced synthesis gas has up to 60% of H₂, as it comes not only from biomass but mainly from steam. The handling of tars is much easier than in other systems, due to presence of excess steam. Heavier tar fraction is separated in a cyclone and introduced back in the hottest zone of the reactor. The synthesis gas with light tar fractions is introduced into a high-temperature cracker, where tars and methane are cracked in presence of steam in lower hydrocarbons and H₂. The removal of other impurities is done in a cryocooler, active-coal and ZnO-filter. It has been proved that combination of high temperature steam with updraft reactor, tar cyclone, and new developed components like thermal cracker and cryocooler is the most effective combination for getting clean gas.

By scaling up the pilot facility, a demonstration facility has been designed. As in the pilot facility, the input biomass is waste material or low-quality wood chips, which cannot be used in other technologies (no tank-plate competition). The advantages are: a) achieved energy efficiency up to 70%, b) electricity consumption lower than 5 kWh/kg H₂, c) production costs considerably lower when compared to the electrolysis based processes for renewable electricity, d) CO₂-emission are under 1 kgCO₂/kgH₂ and e) several useful by-products like biogenic CO₂ or benzenes are obtained.

Abstract

Bioeconomy is becoming a more interesting field for investments in the Republic of Croatia, especially in its small regions and local administrative units. Vukovar-Srijem county is one such unit in eastern Croatia with noticeable potential for development in a circular, carbon-neutral, and sustainable bioeconomy. Due to the nature potential represented by one of the largest forest reservoirs in Europe-Spačva basin, forestry is one of the most important county branches. Aiming to provide more inputs on the wood biomass management, the study on the biomass flow of Vukovar-Srijem county was conducted in 2020 by collecting data from local stakeholders and official reports. The study results have shown that Vukovar-Srijem county has the potential to increase the efficiency level of biomass use, but specific actions on the value-chain strengthening, finalisation of wood products, and innovative ecosystem establishment are still needed. The results highlight the predominant use of sawdust for heating purposes in the VSC region, suggesting potential for optimizing its utilization towards a circular, carbon-neutral, and sustainable bioeconomy, thus offering novel insights for future research and initiatives aiming to maximize economic and environmental benefits from wood biomass residues.

Abstract

Oil-produced waters are the most abundant wastewater stream in oil exploration and production, and their treatment is one of the most expensive processes in the petroleum industry. Since one of the peculiar characteristics of oil-produced waters is the presence of high salinity, developing an effective phytoremediation system for this type of wastewater first requires the selection of salt-tolerant plants. In this contribution, Halocnemum strobilaceum (Pallas) M. Bieb. and Suaeda fruticosa (L.) Forsk. were tested in experiments with mesocosms trials at different saline concentrations and hydrocarbons to study the plants tolerance and the hydrocarbon degradation capacity. The experimental campaign showed species-specific results: Halocnemum showed better tolerance to salt and hydrocarbons, and Suaeda showed better performance as hydrocarbon degradation.

The metagenomic analysis carried out on the roots of the plants at the end of the test highlighted a significant speciation of the microbial communities, especially evident at the family level. The differences detected were found both in the comparison between the different treatments and between the two plant species. In general, the Pseudomonadaceae family was predominant in mesocosms with Suaeda, whereas the Halomonadaceae family was dominant in those with Halocnemum.

In parallel, some strains showing good potential for promoting plant growth were isolated. In conclusion, the experimentation allowed to identify the operating conditions for which the technology could be exploited as a sustainable alternative to consolidated technologies.