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Study region: The Godavari River basin (GRB), situated between the geographical coordinates of 73(degrees)21 ' E to 83(degrees)09 ' E and 16(degrees)07 ' N to 22(degrees)50 ' N, India. Study focus: We developed an integrated framework combining the variable infiltration capacity (VIC) model and geospatial tools to identify potential sites for run-of-river small hydropower plants (RoR-SHP) capable of meeting the GRB's energy demands during El Nino events. This study utilized long-term (1951-2020) daily streamflow data, simulated with the VIC model for design discharge computation at 30%, 75%, and 90% flow dependability and provided a thorough assessment of the potential of RoR-SHP in the GRB. New hydrological insights for the region: The analysis revealed the GRB's potential for RoR-SHP development, identifying 226 potential sites based on the head along the river, with a combined power and annual energy generation estimate of 92 MW and 0.4 TWh/yr, respectively, at 90% flow dependability. After meticulous screening, 11 potential sites based on the head and the power potential demonstrated a decline of 46.03%, 37.97%, and 17.77% in annual energy at 30%, 75%, and 90% flow dependability, respectively, leaving nine sites maintaining the firm power (90% flow dependability) even during El Nino years. Our findings underscore the increased risk of power shortages during El Nino years and emphasize the need to develop appropriate strategies to cope with the risks associated with El Nino events.

Flexibility has increasingly gained attention within the field of electrification and energy transition where a common objective is to reduce the electricity consumption peaks. However, flexibility can increase the risk of grid congestion depending on where and when and it is used, thus an overall system perspective needs to be considered to ensure an effective energy transition. This paper presents a framework to assess electricity users' contributions to grid load peaks by splitting electricity consumption data into subsets based on time and temperature. The data in each subset is separately correlated with the grid load using three correlation measures to assess how the user's consumption changes at the same time as typical grid peak loads occur. The framework is implemented on four different types of business activities at Uppsala municipality in Sweden, which is a large public entity, to explore their behaviors and assess their grid peak load contributions. The results of this study conclude that all four activities generally contribute to the grid peak loads, but that differences exist. These differences are not visible without splitting the data, and not doing so can lead to unrepresentative conclusions. The presented framework can identify activities that contribute the most to unfavorable grid peaks, providing a tool for decision-makers to enable an accelerated energy transition.

The COVID-19 pandemic has had drastic effects on the way we live. With the sudden shift to the home office, a shift in electricity consumption has also taken place between the residential, public, industrial and commercial sectors. Understanding these changes is crucial for a sustainable energy transition, as these changes affect the load and flexibility to adapt. In this study, we quantify the extent to which the COVID-19 pandemic has led to shifts in the electricity consumption patterns. Based on data from around 10,000 smart electricity meters in Stockholm, Sweden, we built a spatio-temporal multivariate regression model at postal code level to predict what the total electricity consumption during the pandemic would have looked like if there were no pandemic, allowing for quantification of the effect of the pandemic as the difference between the predicted and actual consumption, adjusted for differences in temperature. Results of 10-fold cross-validation showed good accuracy with a Mean Absolute Percentage Error (MAPE) of around 5%, with slight variations for season and consumer sectors. The prediction maps allow us to find clusters where electricity consumption changes are highest, showing where changes in the local electricity infrastructure may be needed in the future.

Semiconductor ionic materials (SIM) have recently gained broad attention due to their unique structural and chemical properties that enable efficient proton transport, making them promising materials for advanced fuel cell applications. This mini-review provides an overview of the proton transport phenomena in SIM and discusses their significance and future perspectives. We discuss the different types of SIMs, their proton transport mechanisms, and the factors that affect their performance. Furthermore, we emphasize the correlation between traditional perovskite oxides and SIMs and how this can be leveraged to improve the development of more advanced proton conductors for fuel cells. Also, we have highlighted the Proton-coupled electron transfer (PCET) mechanism in SIM. This mini-review provides a comprehensive overview of the current state of this emerging field, including its scientific foundations, future prospects, and applicable materials, technologies, devices, and basics for proton ceramic fuel cells (PCFCs)., QC 20240412

PV technologies are regarded as one of the most promising renewable options for the transition towards Net Zero. Despite the rapid development of PV systems in recent years, achieving the necessary goals requires more than a threefold increase in annual capacity deployment by 2030. However, current PV systems often fall short of optimal performance due to improper installation angles. In high-latitude cold regions, the actual PV generation capacity is frequently overestimated due to the omission of snow conditions. This study introduces a novel model designed for high-latitude regions to predict local optimal PV installation angle that maximizes PV power generation, utilizing historical weather big data, including snowfall and melting effects. A case study is presented within a Swedish context to demonstrate the implementation of these methods. The results highlight the crucial role snow conditions play in determining PV performance, resulting in an average reduction of 14.7% in annual PV power generation. Optimal installation angle could yield approximately a 4.8% improvement compared to common installation angles. The study also explores the application of snow removal agents, which could potentially increase PV generation by 0.1–2.3%. Additionally, the new PV installation angle successfully captures the impact of the local weather changes on PV power generation, potentially serving as a bridge between climate change adaptation and future PV power generation endeavors., QC 20240229

Design of a sustainable and economical composite structure is challenging due to the often contradicting design drivers such as energy consumption and cost. Therefore, predicting the environmental and economic impact in the early stages of product design results in the significant reduction of energy consumption and cost. Consequently, the impact of contrasting objectives on an optimized carbon fibre reinforced polymer (CFRP) demonstrator is evaluated in this study. This evaluation is performed by integrating a predictive life-cycle assessment and costing framework in a multi-objective optimization methodology. The varying design configurations include designs with and without stiffeners. Furthermore, the impact of end-of-life allocation on the optimized design is also evaluated in this study. The results show a marked difference between the energy consumption of the various optimized designs with energy optimization producing the most efficient solution. However, the mass of the demonstrator increases by 7–9 kg across the different design configurations when the closed loop allocation model is implemented. Consequently, the results show the importance of selecting an appropriate EOL allocation methodology in evaluating the energy consumption of a product. The results also show that the parameters driving the energy consumption (mass and material configuration) and cost (complexity and manufacturability) are varied and often contrasting. The differences in mass, cost, and energy optimized designs further reinforces the importance of coupling cost and energy evaluation in design of sustainable products. Finally, the study demonstrates the need for a holistic life-cycle based assessment in early stage sustainable product design., QC 20240130

Solar irradiance and temperature are two primary factors that affect the energy generation efficiency of solar photovoltaic (PV) systems, meaning that climate change may significantly impact the production of solar energy in the future. In this study, a two-way sensitivity analysis is carried out to determine the energy generation potential under future climate change conditions, and conditions of shadow covering are also considered. The simulation results indicate that the impact of solar irradiance causes the most variation in energy generation, and that shadow covering has a weak impact on the output. In the one-way sensitivity analysis, solar irradiance makes a +/- 18% difference in energy generation, whereas shadow covering represents about +/- 2%. In the future trend of climate change in the world and Taiwan, the energy generation potential can decrease up to 21% and increase 8%, respectively, mainly corresponded by solar irradiance. We suggest that compared with the issue of temperature, the efficiency of solar irradiance usage is more important, especially in view of the global trend toward solar irradiance loss. Taiwan also suffers the issue, but the different trend of climate change impact may make the challenge different.

To address the impacts of climate change, it is imperative to significantly decrease anthropogenic greenhouse gas emissions. Biomass-based chemicals and fuels will play a crucial role in substituting fossil-based feedstocks and reducing emissions. Gasification-based biomass conversion processes with catalytic synthesis producing chemicals and fuels (Biomass-to-X, BtX) are an innovative and well-proven process route. Since biomass is a scarce resource, its efficient utilization by maximizing product yield is key. In this review, the electrification of BtX processes is presented and discussed as a technological option to enhance chemical and fuel production from biomass. Electrified processes show many advantages compared to BtX and electricity-based processes (Power-to-X, PtX). Electrification options are classified into direct and indirect processes. While indirect electrification comprises mostly the addition of H2 from water electrolysis (Power-and-Biomass-to-X, PBtX), direct electrification refers to power integration into specific processing steps by converting electricity into the required form of energy such as heat, electrochemical energy or plasma used (eBtX). After the in-depth review of state-of-the-art technologies, all technologies are discussed in terms of process performance, maturity, feasibility, plant location, land requirement, and dynamic operation. H2 addition in PBtX processes has been widely investigated in the literature with process simulations showing significantly increased carbon efficiency and product yield. Similar studies on direct electrification (eBtX) are limited in the literature due to low technological maturity. Further research is required on both, equipment level technology development, as well as process and system level, to compare process options and evaluate performance, economics, environmental impact and future legislation., Validerad;2024;Nivå 2;2024-03-26 (hanlid);Funder: German Federal Ministry of Economic Affairs and Climate Action (03EE5044B); German Federal Ministry of Education and Research (01DD21005);Full text license: CC BY-NC 3.0

This study investigated self-heating and off-gassing of Scots pine (Pinus sylvestris) wood pellets made from sawdust generated from separated mature and juvenile wood. The pellets were produced at an industrial scale and stored in large piles of about 7.2 tonnes. The production process involved drying the sawdust using three different methods and to varying moisture contents. The results indicated significant influences of both raw material type (F(6) = 61.97, p < 0.05) and drying method (F(2) = 65.38, p < 0.05) on the self-heating of the pellets. The results from the multiple regression analysis further showed that both the raw material type and pellet moisture content significantly influenced the temperature increase, with strong correlations observed for pellets produced using low-temperature drying (F(3, 14) = 83.52, multiple R2 = 0.95, p < 0.05), and medium temperature drying (F(3, 13) = 62.05, multiple R2 = 0.93, p < 0.05). The pellets produced from fresh mature wood sawdust were found to be more prone to self-heating and off-gassing while steam drying the sawdust at high temperature and pressure led to a significant reduction in heat and gas generation across all materials. The heightened self-heating and off-gassing in mature wood pellet can be attributed to a higher proportion of sapwood in the raw material. The probable explanations to the observed differences are in line with biological mechanisms for self-heating and off-gassing, as well as the chemical oxidation of fatty and resin acids.

This study employs COMSOL software v 5.6 to investigate a novel approach to heat transfer via mixed convection in an open hollow structure with an unheated 90° baffle elbow. Two 20 W heat sources are strategically positioned on the cavity’s bottom and right-angled wall for this research. Notably, the orientation of the baffle perpendicular to the airflow is used to direct external, unrestricted flow into the square cavity. The research investigates a range of air velocities (0.1, 0.5, 1.0, and 1.5 m/s) and the intricate interaction between input air velocity, dual heated sources, and the presence of a right-angle baffle on critical thermodynamic variables, such as temperature distribution, isotherms, pressure variation, velocity profile, air density, and both local and mean Nusselt numbers. Validation of the applicable computational method is achieved by comparing it to two previous studies. Significant findings from numerical simulations indicate that the highest velocity profile is in the centre of the channel (2.3–2.68 m/s at an inflow velocity of 1.5 m/s), while the lowest profile is observed along the channel wall, with a notable disruption near the inlet caused by increased shear forces. The cavity neck temperature ranges from 380 to 640 K, with inflow air velocities varying from 0.1 to 1.5 m/s (Re is 812 to 12,182), respectively. In addition, the pressure fluctuates at the channel-cavity junction, decreasing steadily along the channel length and reaching a maximum at the intake, where the cavity neck pressure varies from 0.01 to 2.5 Pa with inflow air velocities changing from 0.1 to 1.5 m/s, respectively. The mean Nusselt number exhibits an upward trend as air velocity upon entry increases. The mean Nusselt number reaches up to 1500 when the entry air velocity reaches 1.5 m/s. Due to recirculation patterns, the presence of the 90° unheated baffle produces a remarkable cooling effect. The study establishes a direct correlation between input air velocity and in

This paper introduces a novel absorber design for a Solar Photovoltaic Thermal (PVT) collector, specifically addressing the persistent issue of cell cracking induced by thermal expansion. Despite considerable research efforts to advance PVT technology, cell cracking remains a critical challenge, contributing to decreased collector efficiency. In contrast to previous studies, this research adopts a unique approach. A novel PVT design is proposed, featuring an aluminium alloy structure with a distinctive 'H'-shaped pattern of expansion cavities positioned between Photovoltaic (PV) cells and the absorber. This innovative design is engineered to mitigate thermal expansion and optimize the overall performance of the collector. A 3-D Computational Fluid Dynamic model, simulated using ANSYS software, validates the proposed PVT design against experimental data from a reference collector. A parametric study explores various H-pattern cavity dimensions, revealing that the 2 mm H-pattern plate cavity design achieves the lowest directional expansion, minimizing the risk of breakage. Results show that the proposed design outperforms the reference collector by 10 %, 2 %, and 8 % in thermal, electrical, and overall efficiency, respectively. Furthermore, the H-pattern design reduces thermal expansion by 20 %, enhancing structural resilience and minimizing the likelihood of PV cell cracking. This study represents a significant advancement in PVT technology, providing a practical and easily implementable solution to the critical issue of cell cracking and presenting an optimal design for real-world applications.

The European Union (EU) has implemented several policies to enhance energy efficiency. Among these policies is the objective of achieving energy-efficient renovations in at least 3% of EU buildings annually. The primary aim of this study was to offer a precise environmental comparison among four similar district-heated multifamily buildings that have undergone identical energy efficiency measures. The key distinguishing factor among them lies in the HVAC systems installed. The chosen systems were as follows: (1) exhaust ventilation with air pressure control; (2) mechanical ventilation with heat recovery; (3) exhaust ventilation with an exhaust air heat pump; and (4) exhaust ventilation with an exhaust air heat pump with a Photovoltaic (PV) panel. This study involved a life cycle assessment that relied on actual material data from the housing company and energy consumption measurements. This study covered a period of 50 years for thorough analysis. A sensitivity analysis was also conducted to account for various future scenarios of energy production. The findings revealed that the building with an exhaust air heat pump exhibited the lowest greenhouse gas emissions and the shortest carbon payback period (GBPT), needing only around 7 years. In contrast, the building with exhaust ventilation without heat recovery showed the highest emissions and the longest carbon payback period (GBPT), requiring approximately 11 years. Notably, the results were significantly influenced by future scenarios of energy production, emphasizing the crucial role of emission factors in determining the environmental performance of distinct renovation scenarios.

Renewable energy sources (RES) and electric vehicles (EVs) are two promising technologies that are widely recognized as key components for achieving sustainable cities. However, intermittent RES generation and increased peak load due to EV charging can pose technical challenges for the power systems. Many studies have shown that improved load matching through energy system optimization can minimize these challenges. This paper assesses the optimal urban-scale energy matching potentials in a net-zero energy city powered by wind and solar energy, considering three EV charging scenarios: opportunistic charging, smart charging, and vehicle-to-grid (V2G). This paper takes a city on the west coast of Sweden as a case study. The smart charging and V2G schemes in this study aim to minimize the mismatch between generation and load and are formulated as quadratic programming problems. Results show that the optimal load matching performance is achieved in a net-zero energy city with the V2G scheme and a wind-PV electricity production share of 70:30. The load matching performance is increased from 68% in the opportunistic charging scenario to 73% in the smart charging scenario and to 84% in the V2G scenario. It is also shown that a 2.4 GWh EV battery participating in the V2G scheme equals 1.4 GWh stationary energy storage in improving urban-scale load matching performance. The findings in this paper indicate a high potential from EV flexibility in improving urban energy system performance., De två första författarna delar förstaförfattarskapet

Faults in photovoltaic (PV) modules may occur due to various environmental and physical factors. To prevent faults and minimize investment losses, fault diagnosis is crucial to ensure uninterrupted power production, extended operational lifespan, and a high level of safety in PV modules. Recent advancements in inspection techniques and instrumentation have significantly reduced the cost and time required for inspections. A novel stacking-based ensemble approach was performed in the present study for the accurate classification of PV module visible faults. The present study utilizes AlexNet (a pre-trained network) to extract image features from the aerial images of PV modules with the aid of MATLAB software. Furthermore, J48 algorithm was applied to perform the feature selection task to determine the most relevant features. The features derived as output from the J48 algorithm were passed onto train eight base classifiers namely, Naïve Bayes, logistic regression (LR), J48, random forest (RF), multilayer perceptron (MLP), logistic model tree (LMT), support vector machines (SVM) and k-nearest neighbors (kNN). The best performing five classifiers on the front run with higher classification accuracies were selected to formulate three categories of stacking ensemble groups as follows: (i) three-class ensemble (SVM, kNN, and LMT), (ii) four-class ensemble (SVM, kNN, LMT, and RF), and (iii) five-class ensemble (SVM, kNN, LMT, RF, and MLP). A comparison in the performance of the aforementioned stacked ensembles was evaluated with different meta classifiers. The obtained results infer that the four-class stacking ensemble model (SVM, kNN, LMT, and RF) with RF as the predictor achieved the highest possible classification accuracy of 99.04%., Validerad;2024;Nivå 2;2024-03-13 (hanlid);Full text license: CC BY-NC

A machine vision driven sensor for estimating the instantaneous feeding rate of pelletized fuels was developed and tested experimentally in combustion and gasification processes. The feeding rate was determined from images of the pellets sliding on a transfer chute into the reactor. From the images the apparent area and velocity of the pellets were extracted. Area was determined by a segmentation model created using a machine learning framework and velocities by image registration of two subsequent images. The measured weight of the pelletized fuel passed through the feeding system was in good agreement with the weight estimated by the sensor. The observed variations in the fuel feeding correlated with the variations in the gaseous species concentrations measured in the reactor core and in the exhaust. Since the developed sensor measures the ingoing fuel feeding rate prior to the reactor, its signal could therefore help improve process control., Validerad;2023;Nivå 2;2023-11-22 (joosat);CC BY 4.0 License

This study presents an in-depth analysis of 69 case studies focusing on the energy retrofit of historic buildings, uncovering challenges, best practices, and lessons learned to balance energy efficiency improvements with heritage preservation. The findings highlight several challenges encountered during renovations, such as complex heritage evaluations, restrictions on alterations, coordination issues with authorities, technical limitations, higher investment costs, and knowledge gaps. On the other hand, identifying factors promoting renovation, including demonstrating energy savings while respecting heritage, early collaboration between planners and authorities, and quantifying investments, could incentivize owners and authorities. The limitations of a still-limited sample size, occasional incomplete data, and potential sample bias call for cautious interpretation of the presented analysis. Despite these, the study provides valuable insights into successful projects, emphasizing the need for scalability, knowledge transfer from innovative policies, and targeted policy-making for successful replication. The study concludes with a call for further development of the HiBERatlas (Historic Building Energy Retrofit atlas), an extensive resource for historic building renovation, expanding its database, collaborating with agencies, and tailoring guidance for stakeholders to foster energy retrofits in heritage buildings.

The transition of energy systems requires policy frameworks and instruments to make both energy suppliers and consumers contribute to the common goal of emission reductions and to fairly allocate costs and benefits among market actors and the government. Assuming that market actors – suppliers and consumers adhering to their economic interests – would benefit from cooperating to mitigate emissions, this study applies a game theory-based approach to investigate the interaction between a local electricity supplier and a group of heating consumers not connected to district heating. Selected policy instruments are tested, and their consequences are analyzed in the context of a representative Nordic municipality. The results show that the auction-based Contract for Difference policy instrument is the most suitable one in the studied Nordic context to achieve significant levels of CO2 emissions reduction. It creates a higher level of strategic interaction between the actors, that would be lacking otherwise, under the form of transfer payments from consumers to supplier, and avoids costs to the general taxpayer. While this is sufficient to promote the investments in renewables by the supplier, additional subsidy policies are required to enable the heating consumers to invest in more capital-intensive energy efficiency measures or biomass heating., Validerad;2024;Nivå 2;2024-03-07 (hanlid);Full text license: CC BY

In order to determine the ideal degree of inclination that should be employed for constructing effective thermal energy storage systems, it is important to examine the impact of inclination angle on the melting behavior of phase change materials (PCMs) such as paraffin wax within a square cell. In consequence, this would guarantee the greatest capacity for energy release and storage. Additionally, analyzing this influence aids engineers in creating systems that enhance heat flow from external sources to the PCM and vice versa. To find out how the cell’s inclination angle affects the melting of PCM of paraffin wax (RT42) inside a square cell, a numerical analysis is carried out using the ANSYS/FLUENT 16 software. Specifically, the temperature and velocity distributions, together with the evolution of the melting process, will be shown for various inclination angles, and a thorough comparison will be made to assess the influence of inclination angle on the PCM melting process and its completion. The findings demonstrated that when the cell’s inclination angle increased from 0° to 15° and from 0° to 30° and 45°, respectively, the amount of time required to finish the melting process increased by 15%, 42%, and 71%, respectively. Additionally, after 210 min of operation, the PCM’s maximum temperature is 351.5 K with a 0° angle of inclination (horizontal) against 332.5 K with an angle of inclination of 45°.

Air pollution significantly threatens human health and natural ecosystems and requires urgent attention from decision makers. The fight against air pollution begins with the rigorous monitoring of its levels, followed by intelligent statistical analysis and the application of advanced machine learning algorithms. To effectively reduce air pollution, decision makers must focus on reducing primary sources such as industrial plants and obsolete vehicles, as well as policies that encourage the adoption of clean energy sources. In this study, data analysis was performed for the first time to evaluate air pollution based on the SPSS program. Correlation coefficients between meteorological parameters and particulate matter concentrations (PM1, PM2.5, PM10) were calculated in two urban regions of Romania (Craiova and Drobeta-Turnu Severin) and Turkey (Adana). This study establishes strong relationships between PM concentrations and meteorological parameters with correlation coefficients ranging from −0.617 (between temperature and relative humidity) to 0.998 (between PMs). It shows negative correlations between temperature and particulate matter (−0.241 in Romania and −0.173 in Turkey) and the effects of humidity ranging from moderately positive correlations with PMs (up to 0.360 in Turkey), highlighting the valuable insights offered by independent PM sensor networks in assessing and improving air quality.

Demand-side flexibility is often encouraged via demand response programs, where users are incentivized to adjust their electricity consumption based on price signals in tariffs. The design and implementation of these signals are vital, as they link conditions of the energy system with user behaviour. As a result of energy system separation into stages of generation, many users are required to simultaneously respond to two price signals. While existing research has mainly examined responses to a single signal, this study highlights the complexities when users must react to two signals simultaneously. It presents a case study using two distinct price signals: real-time pricing (RTP) and a demand charge, analysing the implications such dual price signals could have on users. The study reveals the empirical incompatibility of these signals, leading to conflicting user goals. Such interference complicates decision-making for demand flexibility, potentially eroding user trust in retailers and system operators. The study ends with proposing an alternative tariff, resolving the dual price situation, which facilitates user comprehension and decision-making, and thus enhances the potential for demand flexibility., De två första författarna delar förstaförfattarskapet

The large-scale penetration of electric vehicles (EV) in road transport brings a challenging task to ensure the balance between supply and demand from urban districts. EVs, being shiftable loads can provide system flexibility. This work investigates the potential role of smart charging of EVs in mitigating the impact of the integration of a mix of residential and public EV charging infrastructure on power networks. Furthermore, the impact of integrating solar photo-voltaic (PV) and battery energy storage systems (BESS) has been explored where BESS improves PV self-consumption and helps in peak shaving during peak load hours. Annual losses, transformer congestion, and cost of electricity import assessment are detailed by considering the power network of Stockholm as a case study. Smart charging with loss-optimal and cost-optimal charging strategies are compared to uncoordinated charging. The cost-optimal charging strategy is more favorable as compared to the loss-optimal charging strategy as it provides more incentives to the DSOs. The loss-optimal charging strategy reduces 35.5 % of losses in the network can be reduced while the cost-optimal solution provides a 4.3 % reduction in the electricity cost. The combined implementation of smart charging, PV, and BESS considerably improves energy and economic performance and is more effective than EV smart charging alone., QC 20240307

To evaluate the effects of different energy retrofit scenarios on the residential building sector, in this study, an urban building energy model (UBEM) was developed from open data, calibrated using energy performance certificates (EPCs), and validated against hourly electricity use measurement data. The calibrated and validated UBEM was used for implementing energy retrofit scenarios and improving the energy performance of the case study city of Varberg, Sweden. Additionally, possible consequences of the scenarios on the electricity grid were also evaluated in this study. The results showed that for a calibrated UBEM, the MAPE of the simulated versus delivered energy to the buildings was 26 %. Although the model was calibrated based on annual values from some of the buildings with EPCs, the validation ensured that it could produce reliable results for different spatial and temporal levels than calibrated for. Furthermore, the validation proved that the spatial aggregation over the city and temporal aggregation over the year could considerably improve the results. The implementation of the energy retrofit scenarios using the calibrated and validated UBEM resulted in a 43 % reduction of the energy use in residential buildings renovated based on the Passive House standard. If this was combined with the generation of on-site solar energy, except for the densely populated areas of the city, it was possible to reach near zero (and in some cases positive) energy districts. The results of grid simulation and power flow analysis for a chosen low-voltage distribution network indicated that energy retrofitting of buildings could lead to an increase in voltage by a maximum of 7 %. This particularly suggests that there is a possibility of occasional overvoltages when the generation and use of electricity are not in perfect balance.

QC 20240223

The iron and steel industry is a major emitter of carbon dioxide globally. To reduce their carbon footprint, the iron and steel industry pursue different decarbonization strategies, including deploying bio-based materials and energy carriers for reduction, carburisation and/or energy purposes along their value-chains. In this study two potential roles for biomass were analysed: (a) substituting for fossil fuels in iron-ore pellets induration and (b) carburisation of DRI (direct reduced iron) produced via fully hydrogen-based reduction. The purpose of the study was to analyse the regional demand-driven price and allocative effects of biomass assortments under different biomass demand scenarios for the Swedish iron and steel industry. Economic modelling was used in combination with spatial biomass supply assessments to predict the changes on relevant biomass markets. The results showed that the estimated demand increases for forest biomass will have significant regional price effects. Depending on scenario, the biomass demand will increase up to 25 percent, causing regional prices to more than doubling. In general, the magnitude of the price effects was driven by the volumes and types of biomasses needed in the different scenarios, with larger price effects for harvesting residues and industrial by-products compared to those of roundwood. A small price effect of roundwood means that the incentives for forest-owners to increase their harvests, and thus also the availability of harvest residues, are small. Flexibility in the feedstock sourcing (both regarding quality and geographic origin) will thus be important if forest biomass is to satisfy demands in iron and steel industry., Validerad;2024;Nivå 2;2024-04-08 (marisr);Full text license: CC BY 4.0

The demand for sustainable energy is increasingly urgent to mitigate global warming which has been exacerbated by the extensive use of fossil fuels. Solar energy has attracted global attention as a crucial renewable resource. This study conducted a bibliometric analysis based on publication metrics from the Web of Science database to gain insights into global solar power research. The results indicate a stable global increase in publications on solar power generation and a rise in citations, reflecting growing academic interest. Leading contributors include China, the USA, South Korea, Japan, and India, with the Chinese Academy of Sciences emerging as the most prolific institution. Multidisciplinary Materials Science, Applied Physics, Energy and Fuels, Physical Chemistry, and Nanoscience and Nanotechnology were the most used and promising subject categories. Current hot topics include the systematic analysis of photovoltaic systems, perovskite as a solar cell material, and focusing on stability and flexibility issues arising during photovoltaic-grid integration. This study facilitates a comprehensive understanding of the status and trends in solar power research for researchers, stakeholders, and policy-makers., QC 20240304

After the development of nuclear weapons, civil applications were seen as a way through which protagonists of Soviet modernity could embrace a new future, which Josephson called atomic-powered communism. Where hydro-powered communism had reached its boundaries, nuclear energy was to take over. Crucial parts of the Soviet nuclear industry were based on the use of water. The mantle of progressiveness, innovation, and status previously embodied by the hydropower industry was taken up by emerging nuclear technocrats. While scholars have readily engaged nuclear power as a topic, they have neglected its hydraulic roots and hydro-nuclear entanglements, especially for cooling and other technological purposes. An important but yet overlooked influence came from the creation of Soviet hydraulic-hydropower technological systems. This doctoral thesis fills a twofold gap in the existing literature. First, water is placed at the centre of an analysis of the Soviet nuclear programme. Pipes, valves, tanks, pumps, pressure mechanics and gravity approaches all use much older inventions and engineering mindsets, which are generally not considered in the existing historiography concerning nuclear energy. Aquatic systems, riverbeds, industrial improvements, watersheds, and fluid pathways of potential contamination have not sufficiently been linked to the rapid development of the nuclear industry, even though toxic radioisotopes were spread across the globe. Second, it analyses how technocratic culture influenced nuclear decision-making processes. Therefore, discourses of siting Soviet nuclear power plants in the period between 1954 and 1991 are analysed under a water and technocratic culture perspective to tap more accurately into the links between the nuclear industry, hydraulic engineering, economic imperatives, power and hierarchy, as well as state-communist ideology. The dominant culture present at the construction site of a nuclear power plant determines the circumstances, within w, Med historiska rötter i det sovjetiska atombombsprojektet sågs civila tillämpningar av atomtekniken som ett sätt för förespråkare av sovjetisk modernitet att omfamna en ny framtid, vilket Josephson har kallat “atomdriven kommunism”. Detta innebar att där den vattendrivna kommunismen hade nått sin kapacitet skulle kärnkraften ta över. En betydande del av den sovjetiska kärnkraftindustrin kom att baseras på användningen av vatten. Det nexus av progressivitet, innovation och status som tidigare hade förespråkats av vattenkraftindustrin, antogs även av kärnkraftteknokrater. Medan tidigare forskning har intresserat sig för kärnkraftshistoria i stort, har de hydrauliska och hydro-nukleära aspekterna, särskilt för kylning och andra tekniska ändamål, förbisetts. Skapandet av sovjetiska vatten- och vattenkraftsystem är väsentliga för en heltäckande förståelse av kärnkraftindustrin. Denna doktorsavhandling fyller en dubbel lucka i den befintliga litteraturen. För det första sätts vatten i centrum för en analys av det sovjetiska kärnkraftsprogrammet. Rör, ventiler, tankar, pumpar, tryckmekanik och gravitationsmetoder använder mycket äldre uppfinningar och tekniskt tänkande, som i allmänhet inte tas i beaktande i den befintliga historieskrivningen om kärnenergi. Vattensystem, flodbäddar, industriella förbättringar, vattendelare och vattnet som en väg till potentiell kontaminering har inte i tillräcklig utsträckning kopplats till den snabba utvecklingen av kärnkraftindustrin, även om giftiga radioisotoper kom att spridas över hela världen. För det andra analyserar avhandlingen hur den teknokratiska kulturen påverkade beslutsprocesser inom kärnkraftindustrin. Diskurser rörande placeringen av sovjetiska kärnkraftverk under perioden mellan 1954 och 1991 analyseras med fokus på vatten samt den teknokratiska kulturen för att beskriva kopplingarna mellan kärnkraftindustrin, vattentekniken, de ekonomiska imperativen, hierarkier, och den statskommunistiska ideologin. En utgångspunkt i a, Nach der Entwicklung der Atomwaffen wurden zivile Anwendungen der Kernkraft als legitime Wege gesehen, mit denen die Protagonisten einer sowjetischen Moderne in eine neue Zukunft starten konnten. Diese Zukunft nannte der Historiker Paul Josephson einen durch Atomkraft angetriebenen Kommunismus. Als die Expansionsmöglichkeiten der Wasserkraftindustrie ausgereizt worden waren, sollte die Kernkraft übernehmen. Der Nimbus der Fortschrittlichkeit und der Innovation, der vorher durch die Wasserkraftindustrie verkörpert worden war, wurde nunmehr von den aufsteigenden Technokraten der Atomindustrie übernommen. Obwohl viel zur Kernkraft geforscht worden ist und entscheidende Teile der sowjetischen Atomindustrie auf die Nutzung von Wasser angewiesen waren, blieben die hydrotechnischen Wurzeln und Verflechtungen größtenteils unbeachtet. Ein wichtiger aber bislang vernachlässigter Einfluss kam durch die vorherige Erschaffung des technologischen Systems der Wasserkraftwerke, Kanalbauten und anderer hydrotechnischer Anlagen. Die sowjetische Atomindustrie wurde auf der Grundlage dieser Errungenschaften aufgebaut. Diese Doktorarbeit hilft zwei Lücken in der bisherigen Literatur zu schließen. Erstens wird bei der folgenden Analyse des sowjetischen Atomprogramms das Element Wasser ins Zentrum gerückt. Rohre, Ventile, Tanks, Pumpen, Hydraulik und Schwerkraftansätze gingen alle auf viel ältere Erfindungen und Baudenkweisen zurück. Wassersysteme, Flussbette, industrielle Ameliorationen, Wassereinzugsgebiete und fließende Verbreitungswege von möglicherweise kontaminiertem Wasser wurden nicht hinreichend berücksichtigt und mit der schnellen Entwicklung der Atomindustrie angepasst. Eine Gefahr bildeten dabei giftige Radioisotope, die mittlerweile über Atomkraftwerke in die Umwelt abgegeben und über den ganzen Globus verteilt worden waren. Zweitens wird in dieser Arbeit analysiert, wie eine technokratische Kultur den Entscheidungsfindungsprozess in der Atomindustrie beeinflusst hat. Deshalb, You can reach the author via email: achim.klueppelberg[at]t-online.deQC240301

Hydrogen is a versatile energy vector for a plethora of applications; nevertheless, itsproduction from waste/residues is often overlooked. Gasification and subsequent conversion ofthe raw synthesis gas to hydrogen are an attractive alternative to produce renewable hydrogen. Inthis paper, recent developments in R&D on waste gasification (municipal solid waste, tires, plasticwaste) are summarised, and an overview about suitable gasification processes is given. A literaturesurvey indicated that a broad span of hydrogen relates to productivity depending on the feedstock,ranging from 15 to 300 g H2/kg of feedstock. Suitable gas treatment (upgrading and separation) isalso covered, presenting both direct and indirect (chemical looping) concepts. Hydrogen productionvia gasification offers a high productivity potential. However, regulations, like frame conditions orsubsidies, are necessary to bring the technology into the market., QC 20240215

In 2015 the United Nations (UN) General Assembly agreed on the Sustainable Development Goals (SDGs), a set of 17 goals defined by 169 targets to be reached by 2030. Amongst them is SDG 7. SDG 7 states “Ensure access to affordable, reliable, sustainable and modern energy for all”. The first target of SDG 7 mentions access to electricity and clean cooking specifically. Access to electricity brings with it myriad benefits across several sectors, including residential, health and education. Access to clean cooking can help reduce adverse health and environmental effects, as well as high opportunity costs related to current cooking practices, amongst other benefits. While SDG 7 has been recognized as a key pillar to achieve sustainable development, its achievement has remained elusive. As of 2021, 675 million people worldwide were estimated to lack access to electricity. The largest access gap is found in Sub-Saharan Africa (SSA) where only 50% of the population had electricity access. For clean cooking the situation is worse, with around 2.3 billion people globally lacking access. Again, the access gap is most pronounced in SSA with only 18% of the population in the region using clean cooking. The situation in SSA is further exacerbated by the fact that the population increases faster than the clean cooking access rate. For electricity access modelling Geographic Information Systems (GIS) and the use of geospatial data is being increasingly leveraged. As every case in a study area is unique and requires context-specific information, the spatial dimension of GIS can help to more effectively model towards universal electricity access. Resource availability, fuel costs and access to infrastructure change spatially and a geospatial approach helps to capture this. Such reasoning can also be applied to clean cooking. Yet, at the time of writing this thesis, there was no geospatial tool comparing the relative costs and benefits of different cooking solutions. This work aims t, År 2015 kom Förenta nationernas (FN) generalförsamling överens om en uppsättning av 17 hållbarhetsmål, definierade av 169 delmål. Avsikten är att dessa ska uppnås senast 2030. Bland dem finns mål 7. Mål 7 ämnar att "Säkerställa tillgång till ekonomiskt överkomlig, tillförlitlig, hållbar och modern energi för alla". Det första delmålet för mål 7 nämner specifikt tillgång till elektricitet och ren teknik för matlagning. Tillgång till elektricitet medför många fördelar över olika sektorer, inklusive hushåll, sjukvård och skola. Tillgång till ren teknik för matlagning är också viktig och kan bland annat bidra till att minska skadliga hälso- och miljöeffekter samt höga alternativkostnader relaterade till nuvarande matlagningspraxis. Även om mål 7 har visat sig vara viktigt, har dess uppnående förblivit flyktigt. År 2021 uppskattades 675 miljoner människor världen över sakna tillgång till el. Det största tillgångsgapet återfinns i Afrika söder om Sahara (SSA), där endast 50 % av befolkningen hade tillgång till el. När det gäller ren teknik för matlagning är situationen desto värre, med cirka 2,3 miljarder människor globalt som förlitar sig på icke-rena matlagningsbränslen. Återigen är tillgångsgapet mest påtagligt i SSA, där endast 18 % av befolkningen använder ren matlagning. Situationen i SSA förvärras ytterligare av att befolkningen ökar i snabbare takt än tillgången till ren teknik för matlagning. För modellering av tillgång till elektricitet används alltmer geografiska informationssystem (GIS) och geospatial data. Eftersom varje fall i ett område är unikt och kräver kontextspecifik information, kan geospatial data effektivisera modelleringen mot universell tillgång till elektricitet. Tillgänglighet av resurser, bränslekostnader och tillgång till diverse infrastruktur förändras över ett undersökningsområde och geospatiala metoder hjälper till att inkludera dessa förändringar. Det finns ingen anledning att tro att detta inte gäller även för frågan om ren teknik för mat

Concentration of solar energy may be obtained by reflection, refraction, or a combination of the two. The collectors of a reflection system are designed to concentrate the sun’s rays onto a photovoltaic cell or steam tube. Refractive lenses concentrate light by having it travel through the lens. The sun’s rays are partially reflected and then refracted via a hybrid technique. Hybrid focus techniques have the potential to maximize power output. Fresnel lenses are an efficient tool for concentrating solar energy, which may then be used in a variety of applications. Development of both imaging and non-imaging devices is occurring at this time. Larger acceptance angles, better concentration ratios with less volume and shorter focal length, greater optical efficiency, etc., are only some of the advantages of non-imaging systems over imaging ones. This study encompasses numerical, experimental, and numerical and experimental studies on the use of Fresnel lenses in various solar energy systems to present a comprehensive picture of current scientific achievements in this field. The framework, design criteria, progress, and difficulties are all dissected in detail. Accordingly, some recommendations for further studies are suggested.

Most products today have several functions, but these are achieved by integrating different monofunctional devices and/or materials in a system. Having several functions simultaneously in one single material has many potential advantages, such as a structural material that can also store energy, have self-sensing or self-healing capability or any other physical function. This would lead mass and resource savings, being more energy efficient and thus more sustainable. This paper presents a mini review on how carbon fibres can be used for integrating several functions simultaneously in a high-performance load carrying structural material using the electrical and electrochemical properties of carbon fibres. Through this carbon fibre composites can also store energy like a lithium-ion battery, be used as a strain sensor, have electrically controlled actuation and shape-morphing, and be used as an energy harvester., QC 20240404

Social visions to replace fossil fuels with renewable energy sources have motivated unprecedented growth in global renewable energy manufacturing. Previous literature shows that people committed to realizing such visions have difficulties reconciling with the negative social-ecological impacts of this mass production even if it presents a formidable challenge to a socially just and ecologically sustainable energy transition. This study contributes to a better understanding of how stakeholders view the promises and perils of large-scale renewable energy development. It draws on the petroculure literature to understand how stakeholder viewpoints of deep geothermal energy technology may be a product of the historically unparalleled energy throughput since the mid-20th century. The study relies on Q-methodology for identifying viewpoints among stakeholders in deep geothermal energy in Sweden. The results demonstrate a notable influence of petrocultural assumptions, which helps to explain how stakeholders obfuscate the materiality of renewable energy technologies. This suggests that social visions to replace fossil fuels with technologically sophisticated renewable energy systems could themselves be cultural products of the fossil era inclined to reproduce it., QC 20240222

The upscaling of novel carbon dioxide removal, such as bioenergy carbon capture and storage (BECCS), to gigatonne scales is an urgent priority if global warming is to be limited to well below 2 °C. But political, economic, social, technological, environmental and regulatory uncertainty permeates BECCS projects and deters investors. To address this, we explore options to improve the robustness of BECCS deployment strategies in the face of multi-dimensional uncertainties. We apply Dynamic Adaptive Planning (DAP) through expert interviews and Robust Decision Making (RDM) through exploratory modelling, two decision making under deep uncertainty methods, to the case of Stockholm Exergi, an early mover aiming to deploy BECCS at a combined heat and power plant in the capital of Sweden. The main contributions of the research are to 1) illustrate how a quantification of robustness against uncertainty can support an investment decision to deploy BECCS 2) comprehensively cover uncertain vulnerabilities and opportunities of deploying BECCS, and 3) identify critical scenarios and adaptations to manage these uncertainties. The main conclusions are: investing in BECCS is relatively robust if assessing performance across many scenarios and if comparing the worst-cases of either investing, or not doing so. Not investing could miss out on up to € 3.8 billion in terms of net present value. The critical uncertainties of BECCS can be managed by strengthening biomass sustainability strategies and by gaining support for negative emission trading regulation on carbon markets, e.g., voluntary or Paris Agreement Article 6. Even in vulnerable scenarios of average electricity prices above 82 €/MWh, if trading regulation is implemented before 2030 and if negative emission prices exceed 151 €/CO2, investing in BECCS performs better than not doing so in 96% of cases. We suggest that facility-level parameters and cost-reductions are of little importance for BECCS investments and upscaling. It is r, QC 20240125

Evaluations of price-based demand response programs tend to focus on users' electricity use patterns and/or their practical experiences. Less is known about the effects that price-based demand response programs have on cognitive drivers and barriers to energy-using behaviors and habits, or how well these predict timing of households' electricity use. This study seeks to address this gap by evaluating the effects of a mandatory demand-based time-of-use distribution tariff, using electricity-meter and questionnaire data in an intervention and a reference area, and a structural equation model following the theory of planned behavior. Although no effect was found of the tariff on the actual proportion of peak-hour use, there were significant effects on users’ intentions and motivations to shift electricity use to off-peak hours. The absence of effect on the proportion of peak-hour use seems explained by the facts that only a minority of consumers were aware of their tariffs, and by the (at least partially correct) beliefs that consumers used very little electricity and most of it was already used in off-peak hours. The relationships between intentions, drivers and the actual proportion of peak-hour use were stronger in the intervention area, compared to the reference area. Interestingly, this was true not only for the motivation targeted by the tariff, economic savings, but also for sustainability concerns and social norms. This suggests that effects of the tariff may partly run via other non-monetary motivators., Title in the list of papers of Isak Öhrlund's thesis: Opening the black box of demand response

Building energy forecasting facilitates optimizing daily operation scheduling and long-term energy planning. Many studies have demonstrated the potential of data-driven approaches in producing point forecasts of energy use. Despite this, little work has been undertaken to understand uncertainty in energy forecasts. However, many decision-making scenarios require information from a full conditional distribution of forecasts. In addition, recent advances in deep learning have not been fully exploited for building energy forecasting. Motivated by these research gaps, this study contributes in two aspects. First, this study has adapted and applied state-of-the-art deep learning architectures to address the problem of multi-horizon building energy forecasting. Eight different methods, including seven deep learning-based ones, were investigated to develop models to perform both point and probabilistic forecasts. Second, a comprehensive case study was conducted in two public historic buildings with different operating modes, namely the City Museum and the City Theatre, in Norrköping, Sweden. The performance of the developed models was evaluated, and the predictability of different scenarios of energy consumption was studied. The results show that incorporating future information on exogenous factors that determine energy use is critical for making accurate multi-horizon predictions. Furthermore, changes in the operating mode and activities held in a building bring more uncertainty in energy use and deteriorate the prediction accuracy of models. The temporal fusion transformer (TFT) model exhibited strong competitiveness in performing both point and probabilistic forecasts. As assessed by the coefficient of variance of the root mean square error (CV-RMSE), the TFT model outperformed other models in making point forecasts of both types of energy use of the City Museum (CV-RMSE 29.7% for electricity consumption and CV-RMSE 8.7% for heating load). When making probabilistic pre, Funding: Swedish Energy Agency [50043-1]

Many EU countries have used financial incentives to promote electric light commercial vehicles and decarbonise urban freight transport. However, the high costs of electric light commercial vehicles still pose a significant adoption barrier. This paper evaluates the impact of financial incentives on the total cost of ownership of electric light commercial vehicles in the European Union and their role in achieving the cost-competitiveness of electric vehicles. A pairwise comparison is performed for three weight categories of electric and diesel vehicles in twelve countries. Our analysis shows that financial incentives have a high impact on the total cost of ownership and have proven necessary to achieve electric vehicles' cost-competitiveness in most cases. However, in specific cases, financial incentives may no longer be needed as the cost of electric vehicles' ownership would have been lower than diesel vehicles even without them. This paper demonstrates the importance of adjusting government incentives to avoid unnecessary funding allocations while promoting the decarbonisation of light commercial vehicles, particularly as the number of incentives does not directly correlate with electric vehicles penetration., QC 20240102

Considering inverter as the source of electromagnetic emission signals in a photovoltaic (PV) plant, a comprehensive set of measurements of conducted emissions at the input and output of the inverter in a 10 kW PV plant are presented. These are particularly relevant on the backdrop of (a) ban of products in the EU market due to non-compliance and (b) the increased switching frequency in the inverters ( 100s of kHz) in near future. Specifically, the common mode (CM) and differential mode (DM) currents and voltages are measured, and their frequency domain behavior is studied. It is suggested that conducted emissions from PV can be classified into three zones: viz., extremely low frequency (ELF) zone, power frequency zone, and switching frequency zone. Important observations from this exercise are measurement of harmonic contents of current with total rated current distortion (TRD), imbalance in the output voltage and low frequency ripples in the DC voltage. Frequency domain behavior of the CM quantities is studied which throws light on important points like relation between input and output CM quantities, relation between CM voltage and CM current., QC 20240131

The high penetration of photovoltaic (PV) in power grids typically leads to the displacement of traditional synchronous generators (SGs). However, with a high penetration of PV, fewer SGs are running, and the sharing of responsibility to control the system frequency is reduced and easily exacerbates the problem of reduced inertia response in the power system. This can increase frequency deviation when there is a load-generation imbalance or unexpected disturbances. The limited amount of inertial response from the PV generation means that it cannot provide the same frequency support as SGs. Therefore, this paper suggests a fast frequency control (FFC) technique for the battery energy storage system (BESS) to reduce the instantaneous frequency deviation (IFD) in the Ethiopian grid. The authors specifically provide knowledge of the modeling of droop-type controlled BESS, which can provide additional damping, enhance the inertial ability of the system, and reduce IFD. The simulation results indicate the effectiveness of BESS in mitigating the adverse inertial impact of PV and meeting the necessary grid requirement. The proposed method was tested on the Ethiopian power system model through simulations by using DIgSILENT simulation software. To validate the model, transient frequency simulation studies are performed for various fault conditions, and comparisons are made with and without BESS for different levels of PV penetration., QC 20240108

The maritime shipping industry accounts for 3 % of global greenhouse gas emissions and delivers 90 % of globally traded goods. Maritime shipping is heavily reliant on fossil fuels. There is increasing policy pressure to cut emissions to achieve the Paris Agreement and to meet decarbonization targets. This paper aims to analyze sector coupling for decarbonization and sustainable energy transitions in maritime shipping, exploring the interlinkages between the transport, energy, industry, agriculture and forestry sectors. First, this paper analyses the opportunities and barriers for sector coupling between the maritime shipping sector and other industries. Second, this paper adds new knowledge on the wider implications of sustainable energy transitions and decarbonization for the maritime shipping sector, the role of various stakeholders in supporting or impeding sustainable energy transitions, policy issues at the international, regional and national level and the links to sector coupling. This research uses a mixed methods approach, applying both qualitative research including interviews and quantitative energy modeling. The research thereby links theories from sustainability transitions with techno-economic modeling approaches. Our research finds that the sector couplings between the transport, energy, industry, agriculture and forestry sectors are of growing importance as maritime shipping is transitioning towards decarbonized and renewable marine fuels. At the same time there is competition for scarce natural resources with other sectors, including aviation and road transport. Socio-technical aspects, particularly of financial and political nature, are key factors that determine the speed and direction of the transition, yet they remain under-explored., QC 20231227

Using solar energy and waste heat for medium-temperature thermal applications depends on efficient and economical heat storage development. Developing a compact thermal energy storage system is essential to use excess thermal energy from a source in a process or to shift the utilisation time of solar thermal energy or recovered waste heat. Phase change materials are commonly used for energy storage applications globally. In this work, a latent heat thermal energy storage (LHTES) system with 2.37 kg of Erythritol as the phase change material (PCM) has been studied. A shell and tube heat storage system is selected due to its effectiveness in heat transfer. Synthetic silicone oil Hi-Tech Therm-60 was used as heat transfer fluid. Thermal stability tests in a differential scanning calorimeter (DSC) for a small sample mass and a specifically designed experiment for a larger sample mass were performed to assess the stability of the PCM. The time-dependent temperature distribution inside the storage system and the effect of heat transfer fluid (HTF) inlet temperature on the charging behaviour were studied during the charging process. Charging time and melt fraction have been calculated. No significant change in melting temperature and a 10% reduction in latent heat of PCM was observed in the thermal stability test for a small sample mass in DSC. The charging time of the storage device was observed to be 91–97 min and 195 min for 140 °C and 130 °C HTF inlet temperatures, respectively. The total stored energy in the system was 922 kJ with a Stefan number of 0.59. Temperature variation during the charging process inside the storage also suggests a buoyancy effect, leading to increased natural convection during the melting process., QC 20240102

This paper presents an experimental evaluation of the performance of a solar photovoltaic-thermal (PVT) system in a swine farm at Mirandola in Italy. In this project named RES4LIVE, funded by the EU’s Horizon 2020 program, a PVT system is installed to replace fossil fuel consumption in one of the barns on the farm. The electrical energy from the collectors is utilized to operate the heat pump and provide electricity to the barn, whereas the thermal energy from the collector is stored in a borehole thermal energy storage (BTES) for further use by a 35 kW heat pump. The hybrid solar field consists of 24 covered PVT flat plate collectors (7.68 kWel and 25 kWth) with a total aperture area of 39.3 m2, which can increase the temperature of the heat transfer fluid (HTF) to up to 40 °C. The PVT system is connected to a modular solar central (SC) with a standardized design that can also be used for other similar applications. The hybrid solar system complemented by energy storage is expected to save approximately 20,850 kg CO2/year . The data collected from the PVT system, SC, and BTES are rigorously analyzed to evaluate its overall performance. A comprehensive performance assessment reveals the capability of the solar system to reduce carbon emissions and effectively replace fossil fuel consumption in the agricultural sector.

This work presents novel energy production/storage/usage systems to reduce energy use and environmental effects, in order to address concerns about excessive heating demand/emissions in buildings. This focus is the design, control, and comparison of a biomass-fired model with a novel heater type and a solar-driven system integrated with photovoltaic thermal (PVT) panels and a heat pump. The heater has an external boiler and shell and tube heat exchanger, providing enhanced control over the combustion process and increased efficiency. Another feature of the present work is establishing a rule-based automation framework to manage the energy storage/flow among the components/grid/building. This smart integration reduces the size of the components, eliminates the need for a battery, and allows the system to interact in both directions with the electricity grid. The practicality of both systems is assessed and compared via a code developed in TRNSYS-MATLAB, considering the specific conditions of Toronto, Canada, characterized by high heat demand in winter. According to the results, the proposed solar-based system has an acceptable energy cost (78.9 USD per MWh of heating and electricity) attributable to the developed controllers applied to thermal energy storage. The results show that the PVT-based system integrated with a heat pump is environmentally superior, with a reduction in CO2 emission of 7.2 tonnes over a year. However, the biomass-fired system is an excellent option from the aspect of efficiency, with a relatively high energy efficiency of 69 %. Also, it is observed that the night set-back of the supply temperature can reduce the annual primary energy use and emission up to 60.3 MWh and 21.1 t, respectively. While the system relies more on the heat pump in cold months, the solar energy system supplies the entire demand in summer, demonstrating the significance of PVT and heat pump integration to increase energy reliability throughout the year., QC 20240110

At the time of writing, 759 million people (2019) still lack access to electricity globally. It is important for energy planning to describe plausible pathways to achieve national goals, using tools such as energy systems models to explore scenarios and provide insight. Until recently, modelling energy access in countries with a low electrification rate was conducted at low spatial (e.g., national) and/or temporal resolutions (e.g., annual time slices or ‘overnight’ electrification). In this paper, we develop methods in an open-source computational workflow with high spatial resolution in an open-source energy systems optimisation model. We use Kenya as our case application where approx. 16 million people still lack access to electricity (2019). One reference scenario and two diagnostic hypothetical scenarios are developed to assess the model. The spatial resolution of approximately 40 by 40 km cells leads to 591 demand cells split between electrified and un-electrified population. The results show that in the reference scenario, the optimal supply option for the unelectrified population is PV panels and batteries. At the same, an oversupply of the planned power plants is observed. The model can capture dynamics between spatially explicit supply options and central power plants in one model., QC 20240115

Energy efficiency is a cornerstone of climate change mitigation. For buildings, facility management is an essential part of achieving efficient energy use while keeping tenants satisfied. This interview study explores success factors and barriers for facility management in maintaining energy efficiency over time in four approximately 10-year-old non-residential premises built as so-called nearly zero-energy buildings (nZEB) in Sweden. The study highlights the importance of functional digital tools, benchmarks, and building professionals’ involvement in ensuring energy efficiency. It also emphasizes the need for involvement communication and strategies to engage facility management in energy efficiency efforts. The study suggests that in-house and public policies can play a crucial role in sustaining high ambitions for energy efficiency. Access to professional support that is self-evident to use is identified as a critical success factor. Additionally, the research presents an analytic model that can be used in future studies to assess facility management organizations’ potential for maintaining energy performance in buildings over time.

Bioenergy with carbon capture and storage (BECCS) can be a useful and cost-effective climate change mitigation tool but it is reliant on economic incentives. With this policy perspective article we question the ongoing discussion about the use of biomass for BECCS with basis in three points: (1) under the enhanced transparency framework under the Paris agreement, all parties to the agreement will use the same guidelines to estimate emissions by sources and removals by sinks, in which the emissions and removals in connection to cultivation of biomass are accounted for in the land-use, land-use change and forestry (LULUCF) sector, (2) adding carbon capture to existing processes may lead to a shift in products from that process rather than an increase in biomass use, and (3) BECCS requires substantial financial incentives. With basis in these points, we argue that a certification framework for BECCS that contradicts the guidelines of the Intergovernmental Panel on Climate Change (IPCC) risks unnecessarily hindering deployment of a potentially cost-effective climate change mitigation tool., QC 20231215

Buildings’ energy consumption and greenhouse gas emissions are a major global concern. Healthcare buildings, being crucial to society, pose particular challenges due to their round-the-clock operation and stringent hygiene standards. This paper comprehensively reviews existing literature to promote energy-efficient and comfortable healthcare buildings. The research explores both passive measures, such as orientation, materials, and daylight, and active measures, including Heating, Ventilation, and Air Conditioning systems, energy management, and renewable resources. The paper emphasizes the critical role of user behavior in conserving energy and outlines how factors like building size, operation hours, and climate can impact resource consumption. It highlights the importance of solar power as a prominent renewable energy source. It offers design and retrofitting options to enhance healthcare buildings and addresses the lack of research on small-scale healthcare buildings. The paper emphasizes maintaining a balance between user comfort and energy reduction, involving diverse stakeholders, and exploring benchmarks, automated shading, geothermal sources, local materials, and their impact on carbon emissions. This review aims to contribute to environmentally responsible and socially resilient healthcare infrastructure and provide insights for future challenges in creating energy-efficient healthcare buildings., QC 20231215

Geographical proximity exerts a substantial influence on structural evolution, developmental trajectory, and pace of sociotechnical system growth. This study explores this aspect within the context of the development of forest biomass-based biofuel technology, employing a Technological Innovation System (TIS) framework with the lens of geographical proximity utilization of system components. The research employed a combination of document analysis and interviews with key system stakeholders as data collection methods. The analysis reveals that the close geographical proximity of the system components and technologies, encompassing both technical aspects and sectors, did not result in synergetic effects, in contrast to prior TIS research findings. Rather than fostering collaboration, it has engendered a competitive dynamic, partially driven by actors vying for knowledge leads and funding from both regional and national agencies. Consequently, the potential benefits of geographical proximity of system components remain largely untapped. In light of these results, this study offers practical recommendations for exploiting untapped opportunities, advocating for more strategic use of geographical proximity to foster system technology development and enhance its role in national TIS development. This case study enriches sustainability transition literature by providing valuable insights into the role of geographical proximity in innovation processes.

Tunable bandgaps make halide perovskites promising candidates for developing tandem solar cells (TSCs), a strategy to break the radiative limit of 33.7% for single-junction solar cells. Combining perovskites with market-dominant crystalline silicon (c-Si) is particularly attractive; simple estimates based on the bandgap matching indicate that the efficiency limit in such tandem device is as high as 46%. However, state-of-the-art perovskite/c-Si TSCs only achieve an efficiency of similar to 32.5%, implying significant challenges and also rich opportunities. In this review, we start with the operating mechanism and efficiency limit of TSCs, followed by systematical discussions on wide-bandgap perovskite front cells, interface selective contacts, and electrical interconnection layer, as well as photon management for highly efficient perovskite/c-Si TSCs. We highlight the challenges in this field and provide our understanding of future research directions toward highly efficient and stable large-scale wide-bandgap perovskite front cells for the commercialization of perovskite/c-Si TSCs., Funding Agencies|ZJU-Hangzhou Global Scientific and Technological Innovation Center [02170000-K02013017]; National Natural Science Foundation of China [61721005]

The importance and benefits of transitioning away from fossil fuel based energy systems is becoming ever clearer. The transition is especially crucial for geographic islands that typically have limited, or no, access to mainland energy networks. This limited access means that they must rely on costly, economically and environmentally, imported fossil fuels for energy production. This isolation and reliance on imported fuels makes islands particularly energy insecure, which is only expected to worsen because of climate change. At the same time, much of the current guidance and policy developed to help plan for islands’ energy transition is based on the conditions and circumstances present on the mainland or on energy planning that focuses primarily on technical or economic parameters. To plan for a smoother, more successful transition away from fossil fuel based energy production on islands, more data is needed about islanders themselves and their local circumstances as well as planning guidance flexible enough to fit the variable needs of island planners that goes beyond a techno-economic focus. In this PhD Thesis and in response to these transition issues, an energy planning platform, REACT-DECARB, has been developed to specifically address the needs of island energy planners. This platform seeks to be holistic in its approach to facilitate the island energy transition planning procedure by considering typical island characteristics and energy transition processes while also including key technical, social, environmental and economic dimensions and granting planners flexibility in how they incorporate them. Additionally, surveys and interviews with island residents are conducted to gain an understanding of islanders’ motivations, priorities and awareness in relation to energy and energy transition as well as to determine if these can be of guidance to island energy transition planners. The applications of the REACT-DECARB platform on geographic islands representing

Wind energy expansion has influenced electoral behavior by decreasing support for incumbents, primarily explained by not-in-my-backyard (NIMBY) arguments. However, how does the establishment of wind farms shape electoral behavior when municipal politicians can veto such establishments? Analyzing Sweden, this study shows that voters respond not only by retrospectively evaluating past constructions but also by evaluating parties differently based on their expectations. Our results indicate that parties more likely to approve turbine constructions are punished more than those less expected to do so. Additionally, we find no evidence that the construction of wind turbines influences support for either Green or radical right-wing parties. In conclusion, this study show that the political repercussions of wind farm expansion are multifaceted, influenced by a combination of past actions, future expectations, and the ideological stances of political parties.

Nuclear power is an important part of Sweden's energy system and contributes with about 30 % of the supplied electric energy. Interest in new construction is currently high and one type of reactor that may be built is small modular reactors, SMRs. A method that is used to evaluate the safety of a traditional nuclear power plant is the so called probabilistic safety assessment (PSA). An important question is if PSA is applicable to SMRs. This thesis examines differences between a BWRX-300 type SMR and a generic boiling water reactor to investigate if the traditional PSA method is applicable to SMRs and what characteristics that may affect the results. To investigate the topic, a simplified PSA analysis is carried out at level 1 for five different initiating events: extreme snowfall, loss of cooling accident, loss of main feedwater, loss of offsite power supply and transient. These are then compared to a model of a generic BWR reactor. The conclusions that emerge from the analysis are that the traditional PSA method can be applied for SMRs of the BWRX-300 type. The features that distinguish the BWRX-300 compared to a generic BWR are mainly that the SMR is smaller in size and power and the influence of the passive safety systems. This results in a lower core damage frequency. Some the areas where the PSA method could be developed for SMRs are the analysis of passive components and passive functions.