Electricity Production Potential Research Articles

Energy recovery and hydrogen production potential assessment in a natural gas pressure reduction station

An energy recovery and hydrogen production potential assessment study was carried out for a pressure reduction station by integrating a turbo expander-electrolyzer system. The hydrogen and electricity production potentials were investigated based on the natural gas flow rate. For this purpose, a turbo expander-proton exchange membrane electrolyzer system was considered, using standard data of an RMS-A type PRS. The variation in energy recovery potential was calculated according to the natural gas flow rate and inlet-outlet parameters such as temperature and pressure. By using these parameters, energy balance calculations and energy profit rate were evaluated. The energy profit rate was calculated as 274 kWh for 50.000 Sm3/h volumetric flow rate. Based on real data for a PRS, the electricity and hydrogen production potential were found to be 13.654.567 kW of electricity and 1.532.325,6 Nm3 of hydrogen production with the annual natural gas flow. According to the sensitivity analysis, increasing the station inlet temperature and outlet pressure negatively affected the energy profit rate, while increasing the inlet pressure had a positive effect. The levelized cost of electricity was calculated as 0,056 $/kW, while the levelized cost of hydrogen was found to be 1,989 $/kgH2. These results indicate that energy recovery from the PRSs is feasible and an opportunity to ensure sustainability.

Towards a circular bioeconomy to produce methane by co-digestion of coffee and brewery waste using a mixture of anaerobic granular sludge and cattle manure as inoculum

Coffee processing wastes, such as solid (pulp and husk) and wastewater, co-digested with industrial brewery wastewater, serve as excellent substrates for generating methane in the anaerobic digestion process. This study compared methane production using different compositions of cattle manure (CM) and granular sludge from an Upflow Anaerobic Sludge Blanket (UASB) reactor used in poultry wastewater treatment (GS). Four anaerobic batch reactors (500 mL) were assembled, A (50% CM and 50% GS), B (60% CM and 40% GS), C (70% CM and 30% of GS) and D (60% CM and 40% GS). Equal concentrations of substrates were added to all reactors: pulp and husk pretreated by hydrothermolysis (1 g L−1), coffee (10 g COD L−1) and brewery (1.5 g COD L−1) wastewaters. Assays A, B and C were supplemented with 2 g L−1 of yeast extract, except for assay D. The reactors were operated at 37 °C and pH 7.0. In assay B, the highest CH4 production of 759.15 ± 19.20 mL CH4 g−1 TS was observed, possibly favored by the synergistic interactions between cellulolytic bacteria Christensenellaceae_R-7_group and Methanosaeta archaea, as inferred by genes encoding enzymes related to acetoclastic methanogenesis (acetyl-CoA synthetase). Consequently, the electricity production potential of assay B (45614.08 kWh−1 year−1) could meet the energy demand of a farm producing coffee and beer, contributing to a positive energy balance concerning methane generation.

Industrial waste heat potential and heat exploitation solutions

The industrial waste heat potential in EU countries and UK is assessed using the most recent data, based on an established methodology that allows to estimate this underexplored resource per country, temperature level and industrial branch. This methodology is applied here combining two previous studies using the most recent energy balances data from Eurostat and other indicators of 2021. The waste heat potential and heat demand are then estimated, in order to identify the progress towards reduction of waste energy. It has been revealed that this progress is significant in terms of energy intensity, leading to a reduction of waste heat from 2015 to 2021, but still this heat amount is large and equal to 221.32 TWh/year in 2021. The second part of this work concerns the assessment of three mainstream solutions to exploit this waste heat: direct heat recovery, heat-to-power conversion, and heat upgrading with high-temperature heat pumps. The heat and electricity production potential of these solutions is identified, followed by the estimation of greenhouse gas emissions savings introduced by each one. It has been shown that the direct heat recovery solution brings the highest savings of almost 50 million CO2-eq. tonnes/year, followed by the heat upgrading one.

Perspectives of Electricity Production from Biogas in the European Union

Biogas is a renewable energy source (RES). The aim of this research was to analyze the perspectives of electricity production from biogas in the European Union. The main source of information was data from Eurostat. We analyzed electricity production from biogas in the European Union (EU). The scope of this research was data from 2012 to 2021. First, we presented biogas production by feedstock type across the world. Then, we presented changes in electricity production from biogas in the EU. We used different methods to evaluate the changes in biogas production. First, we used the ARiMA (Autoregressive Moving Average) model to evaluate the stationarity of the time series. Our electricity production from biogas data proved to be stationary. Second, we elaborated on the prognosis of future changes in electricity production from biogas. The largest producer of biogas is the EU, and it is produced from crops, animal manure, and municipal solid waste. Our research found that the largest production from biogas in 2021 took place in Germany, Italy, and France. These countries have the greatest potential for electricity production from biogas, and they have spent significant funds on facilities and technology. Such countries as Ireland, Greece, Spain, France, Croatia, Poland, Portugal, Romania, Finland, and Sweden increased their electricity production from biogas in 2021 compared to 2020. According to our prognosis, the global production of biogas will increase from 62.300 TWh to 64.000 TWh in 2019–2026 (2.7% increase). In 2022–2026, such countries as Estonia (60.4%), Latvia (29.6%), Croatia (27.6%), Slovenia (10.9%), and Poland (8.2%) will increase their electricity production from biogas the most. In 2022–2026, such countries as Italy (0.68%), Portugal (1.1%), Greece (1.5%), Slovakia (2.3%), and Germany (2.6%) will increase their electricity production from biogas the least. Only Romania (−17.6%), Finland (−11.5%), Lithuania (−9.1%), and Malta (−1.06%) will decrease their production of electricity from biogas in 2022–2026. Such countries as Bulgaria (2344%), Denmark (590.9%), Croatia (449%), and France (183%) increased biogas consumption in 2013–2022. A decrease in the inland consumption of biogas in 2013–2022 was observed in Spain, Cyprus, Latvia, Luxembourg, Austria, and Slovenia.

Spatiotemporal management of solar, wind and hydropower across continental Europe

Weather climate fluctuations cause large variations in renewable electricity production, which requires substantial amounts of energy storage to overcome energy drought periods. Based on daily hydroclimatic data and information about renewable power systems covering Europe, here we quantify the complementarity in the solar-wind-hydro energy components of the continental climate system. We show that the spatiotemporal management of renewable electricity production over Europe can induce a virtual energy storage gain that is several times larger than the available energy storage capacity in hydropower reservoirs. The potential electricity production matches the consumption by spatiotemporal management of suitable shares of solar and wind power complemented with the present hydropower. While the mixed renewable energy potential varies less than anticipated at the continental scale, utilization of the complementarity requires new continental electrical transmission lines and stable international trade. We highlight that management models need to consider incentives beyond national boundaries to appropriately benefit from continental climate conditions.

(Invited) Interface Treatments for High-Efficiency MoOx Based Silicon Heterojunction Solar Cells

Silicon based solar cells dominate the market of photovoltaics, which hold the highest potential for green electricity production. A front/back-contacted architecture combined with the silicon-based heterojunction (SHJ) concept realized a world record efficiency of 26.3%1. However, conventional silicon-based doped layers, which work as carrier selective transport layers, are not optically transparent.Transition metal oxides are promising candidates for SHJ solar cells due to their advantageous opto-electronic properties. Molybdenum oxide (MoOx) with high work function (WF) has achieved highly efficient solar cells with 23.5% efficiency2. However, depositing high quality MoOx thin film on top of a-Si:H is challenging due to highly reactive surfaces3. This interaction may result in interfacial oxidation, lower Mo oxidation states and reduced WF4,5. In turn, electrical performances of solar cells featuring MoOx are poorer3 than standard SHJ devices.Several attempts have been made to prevent the reaction between MoOx and (i)a-Si:H. Pre-annealing4 of a-Si:Hand pre-growth of SiOx layer6 have been proposed as effective ways to prevent the degradation of MoOx. Nevertheless, those approaches require extra process steps that make MoOx integration not immediately viable in industrial environment. In our previous work, we proposed a plasma treatment (PT) at MoOx/(i)a-Si:H interface that demonstrated to mitigate dipole effect and resulted in improved cell performance7. After optimizing the interface treatment, even thinner MoOx layer could be applied.The solar cells were fabricated using 260±20 μm 4-inch double-side textured n-type <100> FZ wafers. (i)a-Si:H was deposited by plasma-enhanced chemical vapor deposition on both sides, while (n)a-Si:H only at the rear side. We carried out two different plasma treatments on the (i)a-Si:H interface prior MoOx deposition: one called PT from a mixture of SiH4, H2 and CO2 and another called PTB from a mixture of SiH4, H2, CO2 and B2H6. One sample without plasma treatment (noPT) was used as reference to evaluate the efficacy of the proposed method. A thickness series from 1 to 4 nm of MoOx was thermally evaporated from MoO3 powder at the pressure of 5×10-6 mbar. After that, optimized 50-nm and 150-nm thick tungsten-doped indium oxide (IWO) layers were sputtered through a hard mask at front and rear side, respectively, defining six 2×2 cm2 solar cells per wafer. As metal contact at the front side, we used room temperature Cu plating8 with a metal coverage fraction of 1.575%; at the rear side, 500-nm thick Ag layer was sputtered on the full device area.We studied the impact of different plasma treatment conditions on MoOx film quality and cells’ performance. MoOx film quality was assessed based on O vacancies inside the film4. The samples with interface treatments contain less O vacancies than the sample without treatment. It is noticeable that the cell precursors endowed with PTB yield higher fill factor (FF) than other types of precursors. Instead, PT and noPT samples benefitted from high short-circuit current density (J SC). Ultimately, PTB and PT samples achieved similar conversion efficiency. For the variation of MoOx thickness, we observed that even a slightly change in its thickness influences the solar cells’ electrical performance drastically. An ultra-thin, ~1.7-nm thick MoOx layer could provide sufficient field passivation (open circuit voltage, V OC = 721.4 mV) and good opto-electrical properties (FF = 82.18% and J SC-illuminated-area = 40.20 mA/cm2). With our approach we demonstrate word record cell with ISFH-certified conversion efficiency of 23.83% 9. 1 LONGi Solar 2021. 2 J. Dréon, et al., Nano Energy, 2020. 3 J. Geissbühler et al., Appl. Phys. Lett. 2015. 4 M.T. Greiner, et al., Adv. Funct. Mater. 2013. 5 M.T. Greiner, et al., Adv. Funct. Mater. 2012. 6 J. Tong, et al. ACS Appl. Mater. Interfaces. 2021. 7 L. Mazzarella, et al., Prog Photovolt Res Appl. 2020. 8 C. Han, et al., Solar RRL 2022. 9 L. Cao, et al., Prog. Photovolt. 2022.

Co-digestion of solid-liquid waste from citrus agroindustrial: Effect of hydraulic retention time and organic loading rate on H2 production in a long-term continuous operation leach bed reactor

The Leach Bed Reactor (LBR) application is a promising alternative for the anaerobic digestion of solid waste and wastewater. In this study, the LBR was continuously operated for 160 days in four different phases, for co-fermentation of solid and liquid waste from the citrus agroindustry, at 37 °C, evaluating the effect of hydraulic retention time (HRT) and organic loading rate (OLR). The maximum volumetric hydrogen production (VHPR) was observed at an HRT of 12h (958.3 mLH2.L-1.d-1); however, the highest hydrogen yield (HY) was identified at an HRT of 24h (104.9 mLH2.g-1CHO). Based on the metabolic characteristics of microorganisms identified in higher relative abundance, by 16S rRNA sequencing, such as Lactobacillus, Caproicoproducens, Bifidobacterium, Olsenella, and Solobacterium, an occurrence of chain elongation pathways in the production of butyric and caproic acids was inferred, with hydrogen production resulting from the lactic acid oxidation. The maximum electricity production potential of 16.3 kWh.m-3 liquor was estimated.

Theoretical and Energy Biomass Potential of Heat and Electricity Production in Kosovo

The energy use of residues from agriculture, forestry, and solid waste can foster the transition towards a more renewable energy supply. This paper analyzes the energy potential of the above-mentioned sources for energy applications in Kosovo. The analysis is based on statistical data from different studies and reports, analyzing and calculating them to determine the theoretical and energy biomass potential. Kosovo can increase its self-sufficiency by taking advantage of its rich but under-utilized potential of biomass energy sources. This is a novelty study in this area, considering Kosovo lignite-dominated heat energy and electricity consumption and the available special literature. According to our estimates, the theoretical potential is 6.13 million tons/year, while the biomass energy potential should be around 4.57 million tons/year, including approximately 74.6% of biomass, which can be used for energy needs (heating and electricity). Based on the data and calculations, the available and usable potential shows biomass as an energy source with high potential in Kosovo; its share is very low, but it is reasonable to grow for both environmental and economic reasons.

Geospatial segmentation of high-resolution photovoltaic production maps for Switzerland

Until last year, most of Switzerland’s photovoltaic (PV) installations were built on roof tops. But the amount added is not enough to reach the country’s energy transition goals. With the adjustments of September 2023, the government incentivizes large-scale, free-standing photovoltaic installations. It is now essential to identify the best installation locations and to accurately estimate their production potential. Past studies have assessed different landcover classes, but much of the efforts have gone into separating out zones that are not suitable for PV plants; for technical, economical and also legislative reasons. All along, the underlying radiation data that was used to compute the local energy yield remained at a spatial resolution &gt; 1 km. Given the complex terrain of the southern half of the country, this resolution is not high enough to capture the local variability in production potential. Our study introduces a new methodology to derive solar irradiance at a very high resolution of 25 m. Satellite data is combined with high resolution terrain information to compute accurate horizons and to account for local shading effects. These base radiation maps are then converted into potential electricity production from a PV panels. A comparison of the production from a typically chosen panel tilt with the production that can be achieved when the tilt is locally optimized based on the high-resolution radiation maps underlines the value of our new method. In a first application, this data set was used to estimate the lumped production potential of two major landcover classes in Switzerland: agricultural land and water surfaces, each of them divided into two subclasses. The geospatial segmentation was based on land use maps and the total available area within each class was calculated. Comparing the results to the production potential from Swiss roofs shows that these newly incentivized installation areas have a much higher production potential than the conventional roofs; both, in an absolute sense of total potential production (roofs: 120 TWh/a, agricultural: 2,250 TWh/a, water: 210 TWh/a), and in a relative sense of energy yield per installed capacity, especially in winter (roofs &lt;50kWh/m2, agricultural &gt;100kWh/m2, water ≈100kWh/m2).

Система совместного использования обедненного метана угольных пластов и биогаза для выработки электроэнергии в угольных шахтах

Purpose: Justification and development of new resource-saving technologies aimed at utilization of coal bed methane. The problem of low efficiency of utilization of lean methane-air mixtures is primarily due to the low content of methane itself, which varies significantly depending on the type of coal or concentration. This paper discusses the concept of a co-production system that mixes low-methane methane-air mixtures and biogas to generate power. Methods: Analysis of the possible volumes of utilized methane, biogas requirements and the suitability of the primary feedstock for co-generation of heat and electricity. Selection of appropriate parameters for the processes of utilization of mine methane. Analysis of the merits of the proposed method of utilization of lean coal mine methane. Results: It is recommended that biogas produced by agriculture and forestry in the vicinity of the mines be added to the dry methane stream to obtain the necessary gas concentration for electricity generation. Potential electricity production and greenhouse gas emission reductions have also been evaluated. The result shows that the co-production system can significantly improve the efficiency of poor methane-air mixtures in coal mines. Practical significance: The joint use of lean methane and biogas from straw offers practical advantages both economically, ensuring sufficient energy supply in mines, and as a foundation for broad future prospects. It allows for energy cost reduction and environmental pollution reduction, such as decreasing carbon dioxide emissions.

Asymmetric solar evaporator with salt-resistance capability for freshwater and energy generation

Solar-driven steam generation is a promising solution for addressing the pressing challenges of freshwater and energy scarcity, but the accumulation of salt on the evaporator surface hinders performance by reducing sunlight absorption and blocking water transport. To overcome this limitation, we developed an innovative Janus solar evaporator with asymmetric surface wettability that simultaneously generates energy and clean water. The solar evaporator-based niobium nitride (Nb4N5) nanosheets with broadband absorption and high light-to-thermal conversion capability displayed an excellent high evaporation rate of 2.30 kg m−2 h−1 under 1 kW m−2 irradiation, which was 4.8-fold higher than that of melamine foam evaporator. Notably, the Janus evaporators displayed an excellent evaporation rate of up to 2.10 kg m−2 h−1 in 20wt.% NaCl solution. Furthermore, during steam generation, the hybrid evaporator with a thermo-electricity module produced an open-circuit voltage of 135 mV and a short-circuit current of 14.6 mA under two sun irradiation. Our findings demonstrated that the Janus evaporator with salt-resistance property has significant potential for simultaneous steam and electricity production, offering a promising solution to simultaneously address the water and energy crisis.

Investigating the Cost-Effectiveness of Solar Electricity Compared to Grid Electricity in the Capitals of Middle Eastern Countries: A Residential Scale Case Study

Despite of being rich in fossil fuels, the Middle East is currently the main energy consumer and is projected to have the highest growth in energy demand in the world. Due to its great potential in the Middle East, solar energy can play an important role in the plans of energy decision-makers in the region. According to the studies done so far, no study has been done to show the potential benefit of using home-scale solar systems in the Middle East. Therefore, in this work for the first time, the potential of solar electricity production in the capitals of Middle Eastern countries has been studied using HOMER V2.81 software. The investigations are technical, economic, energy, and environmental, and the studied solar system is connected to the national electricity grid. The results showed that in Nicosia, due to the sale of electricity to the grid, the levelized cost of electricity (LCOE) is equal to -0.759 $, which is the lowest price for produced electricity and leads to a return on investment time of 5.69 years for this system. The solar fraction for the Nicosia station is 92%, which prevents the emission of more than 8 tons of CO2 pollutants during the year. The highest value of LCOE with the amount of $0.25 is related to Sana’a, whose investment return time, solar fraction, and annual CO2 emission prevention amount are 14.1 years, 53%, and 1162 kg, respectively. Ranking analysis was done on the results of 5 outputs of the HOMER software as well as 3 other influential parameters using 4 multicriteria decision-making (MCDM) methods. TOPSIS, GRA, WSM, and AHP methods were used, and the final ranking of each station was considered the average of the 4 methods. According to the results, Cyprus and Kuwait stations were the best and worst, respectively.

Prospects for Bioenergy Development Potential from Dedicated Energy Crops in Ecuador: An Agroecological Zoning Study

Most climate change mitigation scenarios rely on the incremental use of biomass as energy feedstock. Therefore, increasing the share of alternative sustainable energy sources as biomass is crucial to provide both peak and base electricity loads in future scenarios. The bioenergy potential of Ecuador has been addressed for agricultural by-products but not for dedicated bioenergy crops. Agricultural zoning studies have been developed for food crops but not for energy crops. Currently, the bioenergy share of electricity produced in Ecuador (1.4%) comes mainly from the use of sugar cane bagasse from sugar production. This study aims to identify potential sustainable bioenergy resources for continental Ecuador using agroecological zoning methodologies and considerations regarding land management, food security, in-direct land use change and ecological and climate change risks. The results identified 222,060.71 ha available to grow dedicated bioenergy crops and potential electricity production of 8603 GWh/year; giant reed ranks first with a potential net energy yield of 4024 GWh per year, and Manabí province presents the highest potential with 3768 GWh/year. Large-scale deployment of bioenergy in Ecuador would require the study of sustainability considerations of each project. The species studied are traditional bioenergy crops; research on novel species is encouraged.

Analysis of the overall potential for electricity production from farm animals manure in Bulgaria

The increasing energy demand combined with the policies for environmental protection are prerequisite to combine them both into the circular economy conception. The utilization of organic waste which produce greenhouse gases during its disposing through production of electricity by obtained secondary organic compounds is a promising approach for the simultaneously meeting of energy needs and decreasing of carbon footprint from the industry. The successful integration of such technology with well-defined economical and technological benefits is optimization task at local level for each country, city or area. An initial evaluation of the potential of manure generated from farm animals in Bulgaria to be utilized as energy source as a different approach for its treatment to reduce the local generation of greenhouse gases is performed in this study. The well-known and commercialized technology for production of biogas from manure by digestion in biogas reactors where at different treatment conditions could be obtained gas mixtures with up to 65 vol. % content of methane is used. The main challenges in front of the implementation of this technology is the impossibility to collect all of the produced manure and also the high transportation costs for its utilization at a centralized site for biogas production and thereafter its combustion in a large power plant. A conservative analysis of the manure quantity available for utilization from different livestock animals and poultry in Bulgaria is performed based on the statistical data for the available farms and the share of free grazing animals. The contribution of different animals to the biogas production and the calorific value based on the gas mixture content are calculated in details. Unlike most other green energy technologies, this one is characterized by 24-hour availability and according to the calculated data a power plant of 1500 MW thermal power could be realized. The reduction of greenhouse gases emissions and potentially spared CO2 emissions quotas at country level are also calculated. As additionally noted there is a secondary commercial product of the anaerobic manure treatment in bioreactors, the solid residue which is applicable as fertilizer for plants due to its high nutritional value.

Building integrated photovoltaics. Overview of barriers and opportunities

Based on the available literature, the status and prospects for further development of the building integrated photovoltaics (BIPV) market were analyzed. The results of the analysis show that the high investment costs and the lack of information about installed BIPV systems and BIPV technology are a problem for the stakeholders. The BIPV technology is an interdisciplinary problem, so the cooperation of a large number of different experts is important. However, it is not yet at a satisfactory level. Another problem is the overlapping of responsibilities of HVAC installers, interior designers and fa?ade manufacturers. On the other hand, the incentives of the EU regulatory framework and beyond to use RES in both new buildings and renovation of old buildings, as well as the desire for energy independence, encourage the application of BIPV technology. An analysis of the electricity production potential of BIPV integrated into the walls and roof of the building was made for four geographical locations. A comparison of the production of electricity on the walls and on the roof of the building was carried out. The analysis shows that on the four walls of the building, where each wall has the same area as the roof of the building, approximately 2.5 times more electricity than on the roof can be generated. In the absence of available surface for installing a photovoltaic power plant on the roof, the walls represent a great potential for BIPV technology.

WIND RESOURCE ASSESSMENT IN SOUTHERN ALBANIA: DATA COMPARISONS FROM THE BALKAN AND NEW EUROPEAN WIND ATLASES

This article describes a new method to more accurately evaluate the wind potential of 5 areas of interest in southern Albania. Using the WAsP simulation program, the authors were able to compare the wind data from the Balkan Wind Atlas (BWA) and the New European Wind Atlas (NEWA) to real wind measurements in Mamaj, Tepelenë, and showed that NEWA is closer to real wind conditions in Albania than BWA. Furthermore, by analyzing wind speed, power density and wind direction, the authors illustrate BWA and NEWA match closely in the five areas of interest in Albania, although BWA tends to overestimate wind potential more. The wind power class was evaluated and four from the five areas of interest were deemed appropriate for establishing wind farms. The authors analyzed eight different wind turbine types and identified the wind turbine with the highest capacity factor for the region to be SG 2.1-114 wind turbine. The potential electricity production from the proposed wind farms was evaluated using the RETScreen Expert program. This research allows for experts to more confidently use wind atlas data to evaluate wind potential in the region of Southern Albania. Finally, these results confirm the electricity potential from building wind farms in the areas of interest, which will contribute to the fulfillment of energy demand in the country and reduce imports in the energy sector.

Estimation of biogas production potential and greenhouse gas emissions reduction for sustainable energy management using intelligent computing technique

This paper presents estimation of Biogas Production Potential and Greenhouse Gas Emissions Reduction for sustainable energy management using intelligent computing technique. Slaughterhouse wastes present a promising opportunity to partially reduce reliance on fossil-based energy. Biogas technology is regarded as one of the methods used in Ghana and can be used to combat climate change, while meeting demand for energy in the country. The objective of the research seeks to theoretically estimate biogas production potential from livestock and slaughterhouse wastes in Ghana, in order for policymakers to consider biogas technology as a potential source of renewable energy to meet the country's energy demand, while contributing to the SDG goals. This study obtained livestock population data from the Ministry of Food & Agriculture and the Ministry of Fisheries & Livestock from 2010 to 2020, and estimated the livestock waste production from slaughterhouses, biogas generation capacity, electricity production potential, greenhouse gas (GHG) reduction potential and biofertilizer generation capacity of Ghana in the fiscal year 2020. The findings indicated that, in the year 2020, slaughterhouses in Ghana generated 4.205 × 1010 kg of waste which can be used to produce 6.792 × 109 m3 of biogas, electricity generation rate of 7.110 × 109 kwh/year which represents about 43.01% of the total electricity consumed in the country that year. Also, the amount of GHG (CO2) emissions by using methane from the AD is 3.631 × 109 kgCO2. The avoided GHG emissions estimated is 1.075 × 1010 kg and biofertilizer of 4.514 × 108 kg can be produced.

The state of the electrical sector in Western Balkan countries. Case study: Republic of Kosovo

The electricity sector around the world is considered one of the most important sectors, which has a direct impact on the economic development of a country. Based on the increase in energy consumption, the crisis with the emission of high levels of harmful gases - the greenhouse effect and the expansion at the economic level of countries, electricity, namely the increase of energy capacity will remain key issues for future discussion at the global level. Electricity is the engine of the rapid economic development of a country; necessarily the well-being of citizens to access to energy sources and energy stability is a key requirement of every consumer, producer or economic operator. How much capacity do countries in the world have to respond to the increase in energy consumption in the future and what sources will be oriented so that the consequences are minimal for the environment, is a question that needs continuous detailed study and concrete approaches from relevant institutions and professionals in this field. Security in electricity supply is essential for our society and necessary for the 24/7 principle for the digital economy. The recent difficulties caused by the Covid-19 pandemic remind us of the great importance of electricity in all aspects of our lives, from the availability of medical equipment and IT systems - for work from home as a growing trend of systemizing jobs during 2020. Ensuring a secure and reliable electricity supply is of paramount importance to all countries in the world. Considering the Western Balkans as one of the regions which since the 90s most of it has been an area which has emerged from devastating wars and which have affected every sphere, including the energy sector. So, the development of the energy sector is one of the most critical issues in the Western Balkans region. Based on the considerable potential of electricity production from renewable sources, it is considered that the production of electricity from RES will create a stable and functional system of energy production by contributing to the principle of diversification of electricity production and decentralization of the power system. So, renewable energy is considered a promising method for building sustainable and resilient energy systems that provide affordable energy to boost a region economic development, reducing import dependence. The purpose of this scientific research is to discuss the development and current state of electricity production from renewable sources in the Western Balkans, with special emphasis on the Republic of Kosovo. Considering that all Western Balkan countries have set targets or targets for RES in their energy policies but not always these pre-defined targets are easily achievable in practice due to thevarious challenges facing the energy sector in this region.

A theory-guided deep-learning method for predicting power generation of multi-region photovoltaic plants

Recently, clean solar energy has aroused wide attention due to its excellent potential for electricity production. A highly accurate prediction of photovoltaic power generation (PVPG) is the basis of the production and transmission of electricity. However, the current works neglect the regional correlation characteristics of PVPG and few studies propose an effective framework by incorporating prior knowledge for more physically reasonable results. In this work, a hybrid deep learning framework is proposed for simultaneously capturing the spatial correlations among different regions and temporal dependency patterns with various importance. The scientific theory and domain knowledge are incorporated into the deep learning model to make the predicted results possess physical reasonability. Subsequently, the theory-guided and attention-based CNN-LSTM (TG-A-CNN-LSTM) is constructed for PVPG prediction. In the training process, data mismatch and boundary constraint are incorporated into the loss function, and the positive constraint is utilized to restrict the output of the model. After receiving the parameters of the neural network, a TG-A-CNN-LSTM model, whose predicted results obey the physical law, is constructed. A real energy system in five regions is used to verify the accuracy of the proposed model. The predicted results indicate that TG-A-CNN-LSTM can achieve higher precision of PVPG prediction than other prediction models, with RMSE being 11.07, MAE being 4.98, and R2 being 0.94, respectively. Moreover, the performance of prediction models with sparse data is tested to illustrate the stability and robustness of TG-A-CNN-LSTM.

Development of an effective operation system in a magnesium-air desalination cell for electricity production with nitrogen and phosphorus removal

A magnesium-air desalination cell system is developed for electricity production alongside concurrent desalination and wastewater treatment. Synthetic wastewater at three concentrations is used as an anolyte and catholyte with and without a recirculation system to investigate effective operation methods. The operation time was 20 h, and the anolyte was changed every 3 h. The maximum conductivity reduction efficiency (desalination efficiency) at a high concentration of synthetic wastewater was 77.4 % and 51.6 % in operation systems with and without recirculation, respectively. Measured concurrently, the maximum electric energy production (EEP) was 23.8 Wh m−3 in the system with recirculation and 15.6 Wh m−3 in the system without recirculation. The increase of voltage drop in operation without recirculation was due to the high internal resistance of the membrane induced to lower EEP in contrast to the membrane in operation with recirculation. During operation, struvite was produced at high initial concentration of synthetic wastewater in bulk solution and confirmed through Fourier transform-infrared spectroscopy and X-ray diffraction. Ammonia and phosphorous removal was high at high initial concentration of synthetic wastewater. The results indicate that the magnesium-air desalination cell holds great potential for electricity production, salt reduction, and wastewater treatment.