Models that can predict battery cells’ thermal and electrical behaviors are necessary for real-time battery management systems to regulate the imbalance within battery cells. This work introduces a Gaussian Process Regression (GPR)-based data-driven framework that succeeds the Multi-Scale Multi-Dimensional (MSMD) modeling structure. The framework can make highly accurate predictions at the same level as full-order full-distribution simulations based on MSMD. A pseudo-2D model is used to generate training data and is combined with a process that shifts computation burdens from real-time battery management systems to lab data preparation. The testing results highlight the reliability of the GPR-based data-driven framework in terms of accuracy and stability under various operational conditions.

During the COVID-19 pandemic, uncertainty has increased in many areas of both business supply and demand, notably oil demand and pricing have become even more unpredictable than before. Thus, for companies that buy large quantities of oil, effective oil price risk management is crucial for business success. Nevertheless, businesses’ risk appetite, specifically willingness to accept more risk to achieve desired business benefits, varies significantly. The aim of this paper is to deepen the analysis of the effectiveness of employing artificial neural networks (ANNs) in hedging against oil price changes by searching for buy signals for European WTI (West Texas Intermediate) crude oil call options, while taking into account the level of risk appetite. The number of generated buy signals decreases with increasing risk appetite, and thus the amount of capital necessary to buy options decreases. However, the results show that fewer buy signals do not necessarily translate into lower returns g... [more]

This paper discusses the resource, technical, and economic potential of using solar photovoltaic (PV) systems in Belarus and Tatarstan. The considered countries are characterized by poor actinometric conditions and relatively low tariffs for traditional energy resources. At the same time, Belarus is experienced with solar power due to different incentive mechanisms that have been used over the past decade. Moreover, the cost of building solar power plants in Belarus in 2013−2017 was lower than the world average. The cost of electricity production is analyzed depending on the geographical location of sites and the type of owners of solar power plants (i.e., households, businesses and industrial enterprises, electricity producers). Using the data on the cost of photovoltaic systems as presented by IRENA and considering actinometric data for Belarus and Tatarstan, a long-term forecast of PV electricity cost is made. The moments of the break-even points and payback periods are defined for... [more]

This study presents a generic method to upscale a semi-submersible substructure and tower-nacelle-blade for a floating offshore wind turbine from 5 MW to 15 MW and beyond. The effects of upscaling the column radius and/or distance of the floating base are investigated, and a comparison is made with a 15 MW reference design. It is found that scaling column radius increases the mass of the platform and the heave natural period, while scaling column distance raises the center of gravity and metacentric height of the floating system and slightly decreases the heave natural period. The 15 MW reference design addresses these issues through design changes that increase the ballast mass to lower the center of gravity, and increase the added mass to raise the heave natural period. Finally, a method for estimating the scaling of platform parameters with different assumptions is proposed.

Microgrid (MG) is a small-scale grid that consists of multiple distributed energy resources and load demand. The microgrid energy management system (M-EMS) is the decision-making centre of the MG. An M-EMS is composed of four modules which are known as forecasting, scheduling, data acquisition, and human-machine interface. However, the forecasting and scheduling modules are considered the major modules from among the four of them. Therefore, this paper proposed an advanced microgrid energy management system (M-EMS) for grid-connected residential microgrid (MG) based on an ensemble forecasting strategy and grey wolf optimization (GWO) based scheduling strategy. In the forecasting module of M-EMS, the ensemble forecasting strategy is proposed to perform the short-term forecasting of PV power and load demand. The GWO based scheduling strategy has been proposed in scheduling module of M-EMS to minimize the operating cost of grid-connected residential MG. A small-scale experiment is conduct... [more]

The European Union has set itself ambitious emission-reduction targets—becoming carbon neutral by 2050. The member states’ energy systems are increasingly switching to renewable and decentralized configurations, in line with the EU guidelines. This is accompanied by the support for “prosumers”—entities that both consume and generate renewable energy. In parallel, a number of prosumer support schemes are emerging as a result of the search for optimal development paths. At the same time, the COVID-19 pandemic has significantly affected the power market, causing huge anomalies mainly in demand and billing. The objective of the study was to assess the impact of the proposed changes in the prosumer schemes on the level of benefits prosumers obtained, including the performance of sensitivity analyses reflected in different levels and stability of electricity consumption resulting from extreme situations caused by the COVID-19 pandemic. Numerical computer simulations for five predefined prosu... [more]

In recent years, many researchers across the world have addressed the implementation of Building Information Modelling (BIM) in the energy assessment of the built environment. However, several potential issues still need to be resolved in order to utilise the benefits provided by BIM to a maximum degree. To fill this gap, a systematic literature review is conducted in this study to critically investigate the utilisation of BIM tools in energy assessment. To achieve the above-mentioned objective, after shortlisting the relevant papers published hitherto, using keyword searching, a systematic review was undertaken, including the application of BIM in the contexts of different countries, types of BIM tools, BIM and Life Cycle Assessment (LCA) integration, energy affiliations, stakeholders’ involvement and their roles, uncertainty, and sensitivity analysis. The outcomes show the most widely used and effective BIM tools in different types of construction projects in various countries. The r... [more]

The demand for low voltage DC (LVDC) distribution systems is increasing due to the rapid development of power conversion technology, the increase of DC-based digital loads, and the expansion of DC-based distributed generation (DG). For the stable operation of the LVDC distribution system, it is necessary to develop a protection method. In this paper, the fault section is estimated using wavelet transform (WT) in LVDC distribution system. The fault section is classified into a DC line and a DC bus. The characteristics of fault current at each fault section part are analyzed in simple and actual LVDC system. Based on this analysis, the algorithm for fault section estimation is proposed using the detail component after performing WT. The results of fault section estimations are verified through various simulations using EMTP and MATLAB. The fault section estimation can be utilized in the development of protection schemes in LVDC distribution system.

Today, 156 years after the invention of entropy by Clausius, there remains disagreement among the scientific community on what entropy and the phenomenon of entropy increase mean [...]

In order to improve the operating and regulation characteristics of the hydropower unit and to stabilize the load fluctuations, variable-speed pumped storage technology based on converters has been proposed and given more attention recently. However, different from the conventional units, due to the variability of operation conditions, variable-speed units need to develop a load optimization strategy in terms of operating parameter identification to ensure state matching for operation. Therefore, this paper proposes an optimization search step based on the model test curve, and the process of parameter optimization search is elaborated and calculated in the turbine operating condition and pump operating condition, respectively. A mathematical model of the turbine regulation system is established to analyze the influence of speed and guide vane related parameters on the regulation characteristics, and the achievable operating range and regulation capacity in the variable-speed condition... [more]

The publication presents the results of a field test of 2−4 min releases of 96% LNG from a road tanker designed to carry the gas. The release was performed at a pressure of 5.9−6.1 atm at a discharge rate of 1.67−1.78 kg/s from a height of 0.75 m under class B conditions of atmospheric stability. Comparison of the obtained experimental results of the maximum concentrations and the simulation carried out with the EFFECS (11.2.0) software showed that the Gaussian gas model better describes the gas cloud propagation at most control points at this release intensity than the dense gas model. The dense gas model gave only slightly better results along the cloud propagation axis at close distances, not exceeding 25/30 m at ground level. It is shown that concentrations between 71% and 110% LEL are observed at the cloud visibility limit. The maximum value of the temperature drop, in the release axis, at a distance of 4 m amounts to ∆Tmax = 93.3 °C. This indicates that the cloud of the released... [more]

Recent episodes of natural disasters have challenged the resilience of power grids. Adequate distribution grid planning that properly captures the risk aversion of the utility system planner is a key factor to increase the flexibility of distribution networks to circumvent these events. In this paper, we propose a methodology to determine the optimal portfolio of investments in lines and storage devices in order to minimize a convex combination between expected value and CVaR of operational costs, including energy not served, while taking into account the multistage nature of the energy storage management within this context. While the expected value of energy not served has been traditionally employed to tackle routine failures, we also minimize the CVaR of energy not served to address high-impact, low-probability (HILP) events. We illustrate the performance of the proposed methodology with a 54-Bus system test case.

As is widely known, internal combustion engines are not able to complete the expansion process of the gas inside the cylinder, causing theoretical energy losses in the order of 20%. Several systems and methods have been proposed and implemented to recover the unexpanded gas energy, such as turbocharging, which partially exploits this energy to compress the fresh intake charge, or turbo-mechanical and turbo-electrical compounding, where the amount of unexpanded gas energy not used by the compressor is dedicated to propulsion or is transformed into electric energy. In all of these cases, however, maximum efficiency improvements between 4% and 9% have been achieved. In this work, the authors deal with an alternative propulsion system composed of a CNG-fueled spark ignition engine equipped with a turbine-generator specifically dedicated to unexpanded exhaust gas energy recovery and with a separated electrically driven turbocompressor. The system was conceived specifically for hybrid propul... [more]

This paper proposes a new estimation algorithm based on the Luenberger observer methodology and multilayer concept. The proposed multi-layer Luenberger observer (MLO) is implemented in the control structure designated for a two-mass system. Two types of aggregation mechanism are evaluated in the paper. The MLO ensures better estimation quality of the mechanical state variables: motor speed, shaft torque, load speed and load torque, as compared to the classical single observer. The more accurate estimated states, the more precise closed-loop control is guaranteed. MLO is designated for the system where initial conditions of the plant are not known or the state variables can change rapidly (load torque in the considered case). The estimation algorithm and control strategy is evaluated through simulation and experimental tests. The obtained results confirm efficiency of the proposed MLO.

Energy (including thermal) needs are growing rapidly worldwide thus leading to increased energy production. Considering stricter requirements for the employment of non-renewable energy sources, the use of biofuel in energy facilities appears as one of the best options, having high potential for growth that will increase in the long run both in the Baltic region and the European Union as a whole. This publication investigates the possibilities of using various blends of biofuel containing lignin for heat production and emissions to the air during combustion processes. The paper examines the chemical composition of lignin and bottom ash and explores the impact of a different ratio of lignin in the fuel mixture, the effect of the power of biofuel combustion plants (boilers) and the influence of fuel supply to the combustion chamber on gaseous pollutants (CO, NOx, SO2) and particulate matter emissions. The results of the conducted study demonstrate that, in contrast to pure lignin, the con... [more]

In this work, a strategy for scheduling a battery energy storage system (BESS) in a renewable energy community (REC) is proposed. RECs have been defined at EU level by the 2018/2001 Directive; some Member States transposition into national legislation defined RECs as virtual microgrids since they still use the existing low voltage local feeder and share the same low-medium voltage transformer. This work analyzes a REC which assets include PV generators, BESS and non-controllable loads, operating under the Italian legislative framework. A methodology is defined to optimize REC economic revenues and minimize the operation costs during the year. The proposed BESS control strategy is composed by three different modules: (i) a machine learning-based forecast algorithm that provides a 1-day-ahead projection for microgrid loads and PV generation, using historical dataset and weather forecasts; (ii) a mixed integer linear programming (MILP) algorithm that optimizes the BESS scheduling for mini... [more]

This paper proposes a novel methodology to estimate equivalent inertia of an area, observed from its boundary buses where Phasor Measurement Units (PMUs) are assumed to be installed. The areas are divided according to the measurement points, and the methodology proposed can obtain the equivalent dynamic response of the area dependent of or independent of coherency of the generators inside, which is the first contribution of this paper. The methodology is divided in three parts: estimating the frequency response, estimating the power imbalance and estimating inertia through the solution of the swing equation by Least-Squares Method (LSM). The estimation of the power imbalance is the second contribution of this paper, enabling the study of areas that contain perturbations and attending the limitation of methods of the literature that rely on assumptions of slow mechanical power. It can be further divided in three steps: accounting the total power injected, estimating an equivalent load b... [more]

The use of Stirling-cycle-based heat pumps in high-temperature applications and waste heat recovery at an industrial scale is of increasing interest due to the promising role in producing thermal energy with zero CO2 emissions. This paper analyzes one such technology as developed by Olvondo Technology and installed at the pharmaceutical company AstraZeneca in Sweden. In this application, the heat pump used roughly equal amounts of waste heat and electricity and generated 500 kW of steam at 10 bar. To develop and widen the use of a high-performance high-temperature heat pump that is both economically and environmentally viable and attractive, various analysis tools such as exergy analysis and life cycle assessment (LCA) can be combined. The total cumulative exergy loss (TCExL) method used in this study determines total exergy losses caused throughout the life cycle of the heat pump. Moreover, an LCA study using SimaPro was conducted, which provides insight into the different emissions a... [more]

The present work introduces an innovative yet feasible heating system consisting of a ground source heat pump, borehole thermal energy storage, an auxiliary heater, radiators, and ventilation coils. The concept is developed by designing a new piping configuration monitored by a smart control system to reduce the return flow temperature and increase the temperature differential between the supply and return flows. The radiators and ventilation heating circuits are connected in series to provide the heat loads with the same demand. The investigation of the proposed model is performed through developed Python code considering a case study hospital located in Norway. The article presents, after validation of the primary heating system installed in the hospital, a parametric investigation to evaluate the effect of main operational parameters on the performance metrics of both the heat pump and the total system. According to the results, the evaporator temperature is a significant parameter... [more]

This paper provides an evaluation of the stranding risks of coal in Poland. Combining an industrial organization and financial analysis approach, we assess the current economic situation of companies operating within the coal industry and draft forecasts for the future. Based on the global economic outlook for coal, we claim that phasing-out coal will take at least two decades, due to the slow transformation of the energy sector and increasing energy demand. The financial evaluation of coal-dependent companies revealed sound financial conditions due to favorable trends in coal prices in international markets. Therefore, instead of prioritizing a rapid phasing-out of coal, we pledge to make more technological investments that would make burning coal less harmful for the planet and thus efficiently mitigate the negative effects of climate change.

There are various traffic calming measures that can be installed in village transition zones. So far, focus was placed on diversified use of pavement markings, amounts of horizontal deflection, shape of the installed chicanes or central islands, presence of gateway, etc., and their location along the transition zone. However, the combined effect of the different transition zone factors on speed reductions has been rarely studied so far. Authors put forward a hypothesis of there being some determinants, which in combination influence speed reduction. To corroborate the hypothesis on the combined impact of the transition zone features on speed reduction in the village transition zones and to validate the established relationships the authors conducted verification study in transition zones containing chicanes or central islands. To verify this hypothesis the authors studied twenty transition zones and managed to confirm the hypothesis at 95% confidence level. The authors used previously... [more]

Hydropower as stable power installations play an important role among renewable energy sources. Yet, their share in renewable energy is small. Currently, it is only 10% of energy from renewable energy sources (RES), compared to 27% in 2010. Therefore, the aim of this paper is to assess the RES support schemes in Poland related to hydropower, such as green certificates, auctions and FIT, with the use of the Levelized Cost of Electricity (LCOE) analysis in order to determine which support scheme is best incentivizing hydropower development. The evolution of the hydropower support scheme in Poland is presented. The total LCOE and possible revenues from support systems for various segments of hydropower installations are graphically analyzed for two analysis periods (15 and 50 years) and for two discount rates (7% and 11.4%). The analysis shows the great importance of the support schemes in the profitability of the hydropower plants investments. The LCOE graphical analysis proves to be sui... [more]

There is increasing demand in environmental remediation and other sectors for specialized sorbents made from renewable materials rather than hard coals and minerals. The proliferation of new pyrolysis technologies to produce bio-based energy, fuels, chemicals, and bioproducts from biomass has left significant gaps in our understanding of how the various carbonaceous materials produced by these systems respond to processes intended to improve their adsorption properties and commercial value. This study used conventional steam activation in an industrial rotary calciner to produce activated carbon (AC) from softwood biochars made by three novel pyrolysis systems. Steam was injected across four heating zones ranging from 816 °C to 927 °C during paired trials conducted at calciner retention times of 45 min and 60 min. The surface area of the three biochars increased from 2.0, 177.3, and 289.1 m2 g−1 to 868.4, 1092.9, and 744.8 m2 g−1, respectively. AC iodine number ranged from 951 to 1218... [more]

The foundry industry is regarded as one of the most energy-intensive industrial sector due to its energy consumption up to 9 MWh/ton of produced metal. As a result, many companies are trying to increase the energy efficiency of their foundry plants. Since many energy-saving technologies are proposed by manufacturers and the literature, choosing the most appropriate one is a difficult task. Moreover, being updated with the available energy-saving solutions is complicated because of the quick technology advances. Consequently, this paper aims at investigating the recent and future opportunities and investments for reducing the energy consumptions of the technologies of Italian foundry companies. Additionally, it aims at presenting a list of available technological solutions validated by Italian experts. To this end, the Energy Audits developed by 231 plants were analyzed to extract the implemented and planned interventions. Furthermore, the economic data available within the Energy Audit... [more]

Energy management systems (EMSs) have been introduced in electrical power systems to optimize operations of the electrical grid infrastructure and to provide support to the grid operator in terms of optimized decisions [...]