Hot flaring, even from quite high flare stacks, may result in significant heat radiation outside a facility to, e.g., public roads where random passersby may be exposed. The present study suggests a novel method for analyzing a typical flare heat radiation exposure and investigates skin burns that may be inflicted on an exposed person if a facility needs to depressurize in an emergency situation. A typical radiation field from an ignited natural gas vent was taken as the boundary condition, and these values were compared to radiation levels mentioned by the American Petroleum Institute (API 521), e.g., 1.58 kW/m2 and above. Due to facility perimeter fences along roads in larger industry areas, it was assumed that an exposed person may flee along a road rather than in the ideal direction away from the flare. It was assumed that naked skin, e.g., a bare shoulder or a bald head is exposed. The Pennes bioheat equation was numerically solved for the skin layers while the person escapes alon... [more]

We present the current status of time-lapse seismic integration at the Farnsworth (FWU) CO2 WAG (water-alternating-gas) EOR (Enhanced Oil Recovery) project at Ochiltree County, northwest Texas. As a potential carbon sequestration mechanism, CO2 WAG projects will be subject to some degree of monitoring and verification, either as a regulatory requirement or to qualify for economic incentives. In order to evaluate the viability of time-lapse seismic as a monitoring method the Southwest Partnership (SWP) has conducted time-lapse seismic monitoring at FWU using the 3D Vertical Seismic Profiling (VSP) method. The efficacy of seismic time-lapse depends on a number of key factors, which vary widely from one application to another. Most important among these are the thermophysical properties of the original fluid in place and the displacing fluid, followed by the petrophysical properties of the rock matrix, which together determine the effective elastic properties of the rock fluid system. We... [more]

In numerous electric drive applications, the mechanical phenomena in the velocity or position control loop determine real difficulties and challenges for the control system. So-called two-mass drive systems with a flexible shaft are the most important example of this situation. The problem becomes even more difficult if the characteristics of torque transmission along the shaft are nonlinear, nonlinear friction is present, and the plant parameters are unknown, as it happens in numerous robotic systems. A novel adaptive controller is derived for such a system. The recurrent design procedure is based on proper modifications of the adaptive backstepping scheme, including non-strict-feedback plant application, tuning functions to exclude controller overparameterization, robust adaptive laws, proper means to avoid controller complexity explosion, and a nonlinear PI controller in the initial loop to minimize quasi-steady-state tracking error. The closed-loop system uniform ultimate boundedne... [more]

To reach sustainable aviation, one approach is to use electro-fuels (e-fuels) within the gas turbine engines. E-fuels are CO2-neutral synthetic fuels which are produced employing electrical energy generated from renewable resources, where the carbon is taken out of the atmosphere or from biomass. Our approach is, to find e-fuels, which can be utilized in the lean premixed prevaporized (LPP) combustion, where most of the non-CO2 emissions are prevented. One of the suitable e-fuel classes is alcohols with a low number of carbons. In this work, the autoignition properties of propanol isomers and butanol isomers as e-fuels were investigated in a high-pressure shock tube (HPST) at temperatures from 1200 to 1500 K, the pressure of 10 bar, and lean fuel-air conditions. Additional investigations on the low-temperature oxidation and flame speed of C3 and C4 alcohols from the literature were employed to develop a comprehensive mechanism for the prediction of ignition delay time (IDT) and laminar... [more]

In this study, shale cores from 20 wells in the S1l11-1 sublayer of Longmaxi Formation buried in shallow shale (3500 m) in the southern Sichuan Basin, China were collected to compare their pore structures and gas-bearing properties using multiple experiments. Results showed that the deep layer has relatively lower brittle mineral content, which is disadvantageous in terms of the higher requirements it imposes on hydraulic fracturing. Results also showed that the most important factor controlling the differential enrichment of S1l11-1 shale gas in southern Sichuan Basin is porosity. Moreover, the porosity composition of shallow shale and deep shale has significant differences: the porosity of shallow shale is dominated by organic pores, while for deep shale, both organic and inorganic pores are important. The inorganic pores provide significant storage space for free gas in deep shale; their contribution warrants more attention. We also found that the difference in organic porosity of t... [more]

Special Economic Zones (SEZs), an important engine of industrial economic development in China, consume large amounts of energy resources and emit considerable CO2. However, existing research pays little attention to industrial energy usage in SEZs and ignores the heterogeneity of administrative hierarchy and regional location. Considering the dual heterogeneity, this study proposes an improved two-dimension and two-level meta-frontier data envelopment analytical model to decompose the industrial electricity efficiency (IEE) and electricity-saving potential of SEZs in Guizhou Province, China, based on 4-year field survey data (2016−2019). Results show that the IEE rankings of three administrative hierarchies within SEZs are provincial administration SEZs, county administration SEZs, and municipality administration SEZs. The SEZs located in energy resource-rich areas and better ecological environmental areas have higher IEE than those in resource-poor areas and ecology fragile areas, re... [more]

This work determines the variation in the fatigue loading on a tidal turbine at two depth positions and two different locations within a site. Site data were obtained at the European Marine Energy Centre, EMEC, test facility in Scotland, which has been compiled at the University of Edinburgh. The turbine modelled is the 18m Diameter DEEP-gen 1MW horizontal axis turbine. A blade element method is combined with a synthetic turbulence inflow to determine forces along the blade over a period of five tidal cycles. The focus is on establishing the difference between the loads at one tidal site, with an emphasis on the variety of turbulent conditions, with the onset flow fluctuations as great as 17% and the average integral lengthscales varying from 11 to 14 m at hub height. Fatigue loading is assessed using damage equivalent loads, with a 30% variation between turbine positions and 32% between turbine locations within a site, for one design case. When long term loading is assessed, a 41% dif... [more]

This paper proposes a procedure for the accurate modelling of the ring induction motors (RIMs), based on the Monte Carlo (MC) method and the relations presented in the relevant metrology guidelines. Modelling was carried out based on the measured data for the torque-slip characteristic (TSC) and using the equivalent circuit for the RIM. The parameters included an extended Kloss equation (EKE) and the associated uncertainties were determined using the MC method. The polynomial procedure was applied as a numerical tool to complement the MC method to determine the power losses in the stator iron and the relevant uncertainty. This is in line with international standards for the theory of uncertainty application in the field of engineering. The novelty of this paper refers to the accurate modelling of the RIMs obtained by determining the corresponding uncertainties. The procedure presented in this paper was developed based on the assumption that the parameters of the equivalent circuit are... [more]

Offshore wind farms (OWFs) are important infrastructure which provide an alternative and clean means of energy production worldwide. The offshore wind industry has been continuously growing. Over the years, however, it has become evident that OWFs are facing a variety of safety and security challenges. If not addressed, these issues may hinder their progress. Based on these safety and security goals and on a Bayesian network model, this work presents a methodological approach for structuring and organizing expert knowledge and turning it into a probabilistic model to assess the safety and security of OWFs. This graphical probabilistic model allowed us to create a high-level representation of the safety and security state of a generic OWF. By studying the interrelations between the different functions of the model, and by proposing different scenarios, we determined the impacts that a failing function may have on other functions in this complex system. Finally, this model helped us defi... [more]

The article discusses the results of biomonitoring research at the Underground Gas Storage (UGS). Hydrogen sulphide, as one of the products of microbiological reaction and transformation, as well as a product of chemical reactions in rocks, is a subject of interest for global petroleum companies. The materials used in this research work were formation waters and stored natural gas. The biomonitoring of reservoir waters and cyclical analyses of the composition of gas stored at UGS Wierzchowice enabled the assessment of the microbiological condition of the reservoir environment and individual storage wells in subsequent years of operation. Investigations of the formation water from individual wells of the UGS Wierzchowice showed the presence of sulphate reducing bacteria bacteria (SRB), such as Desulfovibrio and Desulfotomaculum genera and bacteria that oxidize sulphur compounds. In the last cycles of UGS Wierzchowice, the content of hydrogen sulphide and sulphides in the reservoir water... [more]

Integrating data analytics, optimisation and dynamic control to support energy services has seen significant interest in recent years. Larger appliances used in an industry context are now provided with Internet of Things (IoT)-based interfaces that can be remotely monitored, with some also provided with actuation interfaces. The combined use of IoT and edge computing enables connectivity between energy systems and infrastructure, providing the means to implement both energy efficiency/optimisation and cost reduction strategies. We investigate the economic implications of harnessing IoT and edge/cloud technologies to support energy management for HVAC (Heating, Ventilation and Air Conditioning) systems in buildings. In particular, we evaluate the cost savings for building operations through energy optimisation. We use a real use case for energy optimisation as identified in the EU “Sporte2” project (focusing on the energy optimisation of sports facilities) and explore several scenarios... [more]

District heating (DH) has a major potential to increase the efficiency, security, and sustainability of energy management at the community scale. However, there is a huge challenge for decision makers due to the lack of knowledge about thermal energy demand during a year. Thermal energy demand is strongly dependent on the outdoor temperature, building area, and activities. In this context, this paper presents an innovative monthly thermal energy mapping method to calculate and visualize heat demand accurately for various types of buildings. The method includes three consecutive phases: (i) calculating energy loss, (ii) completing a dataset that includes energy and building information, and (iii) generating the monthly heat demand maps for the community. Determining the amount of demand and the best location for energy generators from the perspective of energy efficiency in a DH system in an urban context is one of the important applications of heat maps. Exploring heat demand character... [more]

Solar panels have been widely criticized for their weather dependence and slowly improving efficiency. Several external factors can further increase the efficiency of solar panels, e.g., shading effect and surface contamination. We investigated the warming effect and the negative impact of these factors on energy production during the research. The continuous operation at high temperatures can modify the crystal structure of solar cells in these hot spots. The electroluminescence (EL) images and thermal imaging measurements show crystal structure failure. In addition to structural damage and rapid aging of the solar cells, contaminants can cause power losses of up to 10%.

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

To sustain the complexity of growing demand, the conventional grid (CG) is incorporated with communication technology like advanced metering with sensors, demand response (DR), energy storage systems (ESS), and inclusion of electric vehicles (EV). In order to maintain local area energy balance and reliability, microgrids (MG) are proposed. Microgrids are low or medium voltage distribution systems with a resilient operation, that control the exchange of power between the main grid, locally distributed generators (DGs), and consumers using intelligent energy management techniques. This paper gives a brief introduction to microgrids, their operations, and further, a review of different energy management approaches. In a microgrid control strategy, an energy management system (EMS) is the key component to maintain the balance between energy resources (CG, DG, ESS, and EVs) and loads available while contributing the profit to utility. This article classifies the methodologies used for EMS b... [more]

Energy system models for the analysis of future scenarios are mainly driven by the set of energy service demands that define the broad outlines of socio-economic development throughout the model time horizon. Here, the long-term effects of the COVID-19 pandemic on the drivers of the industrial production in six energy-intensive subsectors are addressed using Vector AutoRegressive models. The model results are computed either considering or not considering the effects of the pandemic. The comparison to established pre-pandemic trends allows for validating the robustness of the selected model. The anticipated effect of the pandemic to 2040 shows a long-term reduction by 3% to 10%, according to the different subsector, in the industrial energy service demand. When the computed service demands are used as input to the TIMES-Italy model, which shows good capability to reproduce the energy consumption of the industrial sectors in the period 2006−2020, the impact of the pandemic on energy con... [more]

Despite recognizing that climate change and its impacts are not gender-neutral, only few studies address the arising complexities. While in some climate-relevant sectors, such as the transport sector, there already is some initial research on the relationship between climate and gender, research on the climate−gender nexus in the coal sector is still underdeveloped, and the few existing studies focus on dichotomous relations (gender−coal and coal−climate). This article discusses the currently neglected climate, coal, and gender triad and develops a conceptualization along the following aspects: (i) common lines of arguments, (ii) shortcomings in predominant arguments, and (iii) the state-of-the-art regarding the climate−gender−coal triad. To illustrate this outline, it uses the empirical case of the Colombian coal sector. Based on original data obtained via semi-structured interviews, it analyzes how imminent national-level climate policies for the coal sector, i.e., an energy transiti... [more]

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

‘Belt and Road Initiative’ (B&R) countries play critical roles in mitigating global carbon emission under the Paris agreement, but their driving factors and feasibility to reduce carbon emissions remain unclear. This paper aims to identify the main driving factors (MDFs) behind carbon emissions and predict the future emissions trajectories of the B&R countries under different social-economic pathways based on the extended STIRPAT (stochastic impacts by regression on population, affluence, and technology) model. The empirical results indicate that GDP per capita and energy consumption structure are the MDFs that promote carbon emission, while energy intensity improvement is the MDF that inhibits carbon emission. Population, as another MDF, has a dual impact across countries. The carbon emissions in all B&R countries are predicted to increase from SSP1 to SSP3, but emissions trajectories vary across countries. Under the SSP1 scenario, carbon emissions in over 60% of B&R countries can pea... [more]

Electricity prices are the key instrument for coordinating electricity markets. For long-term market analyses, price determination based on fundamental unit commitment simulations is required. Within the European wholesale market, electricity prices result from a market clearing, which finds a welfare-optimal price−quantity tuple considering a coupling of multiple market areas with limited transmission capacity. With increasing exchange capacities in Europe, the precise modeling of the market coupling is required. Many market simulation models use multi-stage approaches with a separation of market coupling and price determination. In this paper, we analyze a new single-stage approach that combines both steps and theoretically and empirically demonstrate its precision by a backtest. For this purpose, we compare a simulated versus a historical electricity price distribution. Moreover, we explain the necessary adjustments for future regulatory developments of the European electricity mark... [more]

This article aims to examine the impact of corporate social responsibility, trust, and sustainable business strategies on the diffusion of innovative solutions in renewable energy sources. In this context, the material from the edition of the reports of the Polish Agency for Enterprise Development on innovation in the renewable energy industry was analyzed. A survey was also conducted among enterprises from the SME sector on the creation of a business model taking into account the diffusion of innovation in the field of renewable energy sources. The SME sector consists of entities that usually do not have an extensive organizational structure or research and development teams. Nevertheless, in the current economic situation, it is required that they are highly competitive, including through implemented innovations. Conscious participation of SME entities in the process of diffusion of innovation may be a solution that brings innovative solutions closer. The author stated that social re... [more]

The concept of hybrid high-voltage alternating current (HVAC) and high-voltage direct current (HVDC) grid systems brings a massive advantage to reduce AC line loading, increased utilization of network infrastructure, and lower operational costs. However, it comes with issues, such as integration challenges, control strategies, optimization control, and security. The combined objectives in hybrid HVAC−HVDC grids are to achieve the fast regulation of DC voltage and frequency, optimal power flow, and stable operation during normal and abnormal conditions. The rise in hybrid HVAC−HVDC grids and associated issues are reviewed in this study along with state-of-the-art literature and developments that focus on modeling robust droop control, load frequency control, and DC voltage regulation techniques. The definitions, characteristics, and classifications of key issues are introduced. The paper summaries the key insights of hybrid HVAC−HVDC grids, current developments, and future research dire... [more]

A new technique, fracturing-and-flowing (frac-n-flow) testing, is introduced for horizontal drilling and multistage hydraulic fracturing (HDMHF) practitioners to check if the next stage would be a brittle fracture using the instantaneous shut-in pressure (ISIP) from the current stage. It was developed to reduce the number of not-flowing clusters in HDMHF treatments due to stress shadows in the development of tight oil reserves in Wolfcamp, Permian Basin, USA, and other similar fields. Preliminary frac-n-flow testing results show that a medium (200−1000 psi) increase in confining pressure under representative field in-situ stresses can transfer Indiana limestone from brittle fracturing to semi-ductile failing. Consequently, folds of increase (FOI) of matrix permeability vary from +13 (i.e., increase by 1300%) to −0.39 (i.e., decrease by 39%). Limestone is one of the major lithological components in Wolfcamp formation. Field ISIP data of two HDMHF wells in Wolfcamp formation show that th... [more]

The process of wind farm operation requires proper logistics services, consisting of the supply of all resources necessary in this process. A critical moment in the operation of wind farms is the implementation of the repowering process, in the form of replacement of the basic elements of wind farms: blades, hub rotors, nacelles or even towers. The replacement of these basic elements of the wind farm relates to the necessity to provide logistics services for heavy and oversized deliveries. Therefore, this article presents a unique analysis of logistics processes related to wind farms. Therefore, the aim of the article is to identify the most energy-saving variant of logistics service of the wind farm repowering process. However, the criterion of selecting the optimal variant is based on the original methodology of energy consumed during logistics services, as opposed to the traditionally used cost-effectiveness criterion. The SolidWorks software with other methods and tools were used f... [more]

This paper offers three easy-to-use metaphor-less optimization algorithms proposed by Rao to solve the optimal power flow (OPF) problem. Rao algorithms are parameter-less optimization algorithms. As a result, algorithm-specific parameter tuning is not required at all. This quality makes these algorithms simple to use and able to solve various kinds of complex constrained optimization and engineering problems. In this paper, the main aim to solve the OPF problem is to find the optimal values of the control variables in a given electrical network for fuel cost minimization, real power losses minimization, emission cost minimization, voltage profile improvement, and voltage stability enhancement, while all the operating constraints are satisfied. To demonstrate the efficacy of Rao algorithms, these algorithms have been employed in three standard IEEE test systems (30-bus, 57-bus, and 118-bus) to solve the OPF problem. The OPF results of Rao algorithms and the results provided by other swa... [more]