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[en] Highlights: ► Analyze mutual interactions and restrictions within energy management systems. ► Tackle uncertainties expressed as fuzzy sets, and regular and radial intervals. ► Obtain optimal solutions under preferred satisfaction degrees and system benefits. ► Use protection level to reflect tradeoffs between constraint-violation and system reliability. ► Provide decision makers with effective energy management schemes. - Abstract: In this study, a fuzzy radial interval linear programming (FRILP) model was developed for supporting robust planning of energy management systems with environmental and constraint-conservative considerations, facilitating the reflecting of multiple uncertainties that are existing in energy activities and environmental emissions and could be expressed as fuzzy sets, and regular and radial intervals. Particularly, it could ensure the generation of robust solutions that would be feasible with high probability under input data variations, reflecting tradeoffs between the conservatism levels of solutions and probability levels of constraint violation. Specifically, 24 radial intervals associated with the electricity generation efficiency and electricity demands under different protection levels based on the natural and technologic conditions, as well as decision makers’ expectation were determined. Totally, 30 scenarios under the combinations of five protection levels were analyzed. Through solving the developed model, the results showed that decision variables would be rising with the increase of protection levels and higher radii fluctuation levels of radial intervals would cause higher system cost and lower satisfaction degree. The generated solutions could offer detail energy management plans (e.g., energy conversion technology capacity expansions) for decision makers, and thus could guarantee optimal economic and environmental benefits under desirable system reliability.
[en] Highlights: • In this paper an expert energy management system (EEMS) is presented. • A power forecasting module for wind generation capacity is presented. • The objective functions that must be minimized are operating cost and net emission. • A smart energy storage system (EES) for electrochemical batteries is presented. • A new modified Bacterial Foraging Optimization (MBFO) algorithm is presented. - Abstract: Recently, the use of wind generation has rapidly increased in micro-grids. Due to the fluctuation of wind power, it is difficult to schedule wind turbines (WTs) with other distributed energy resources (DERs). In this paper, we propose an expert energy management system (EEMS) for optimal operation of WTs and other DERs in an interconnected micro-grid. The main purpose of the proposed EEMS is to find the optimal set points of DERs and storage devices, in such a way that the total operation cost and the net emission are simultaneously minimized. The EEMS consists of wind power forecasting module, smart energy storage system (ESS) module and optimization module. For optimal scheduling of WTs, the power forecasting module determines the possible available capacity of wind generation in the micro-grid. To do this, first, an artificial neural network (ANN) is used to forecast wind speed. Then, the obtaining results are used considering forecasting uncertainty by the probabilistic concept of confidence interval. To reduce the fluctuations of wind power generation and improve the micro-grid performances, a smart energy storage system (ESS) module is used. For optimal management of the ESS, the comprehensive mathematical model with practical constraints is extracted. Finally, an efficient modified Bacterial Foraging Optimization (MBFO) module is proposed to solve the multi-objective problem. An interactive fuzzy satisfying method is also used to simulate the trade-off between the conflicting objectives (cost and emission). To evaluate the proposed algorithm, the EEMS is applied to a typical micro-grid which consists of various DERs, smart ESS and electrical loads. The results show that the EEMS can effectively coordinate the power generation of DERs and ESS with respect to economic and environmental considerations
[en] Highlights: • Improving the utilization of wind power by the demand response of residential hybrid energy system. • An optimal scheduling of home energy management system integrating micro-CHP. • The scattered response capability of consumers is aggregated by demand bidding curve. • A stochastic day-ahead economic dispatch model considering demand response and wind power. - Abstract: As the installed capacity of wind power is growing, the stochastic variability of wind power leads to the mismatch of demand and generated power. Employing the regulating capability of demand to improve the utilization of wind power has become a new research direction. Meanwhile, the micro combined heat and power (micro-CHP) allows residential consumers to choose whether generating electricity by themselves or purchasing from the utility company, which forms a residential hybrid energy system. However, the impact of the demand response with hybrid energy system contained micro-CHP on the large-scale wind power utilization has not been analyzed quantitatively. This paper proposes an operation optimization model of the residential hybrid energy system based on price response, integrating micro-CHP and smart appliances intelligently. Moreover, a novel load aggregation method is adopted to centralize scattered response capability of residential load. At the power grid level, a day-ahead stochastic economic dispatch model considering demand response and wind power is constructed. Furthermore, simulation is conducted respectively on the modified 6-bus system and IEEE 118-bus system. The results show that with the method proposed, the wind power curtailment of the system decreases by 78% in 6-bus system. In the meantime, the energy costs of residential consumers and the operating costs of the power system reduced by 10.7% and 11.7% in 118-bus system, respectively.
[en] An energy management system with an electronic gearshift and regenerative braking is presented to improve the gross efficiency and driving range of an electric scooter, driven directly by a four-phase axial-flux DC brushless wheel motor. The integration of stator windings, batteries, ultracapacitors, and a digital controller constitutes an energy management system, which features smooth electronic gear shifting and regenerative braking. The gross efficiency of the experimental scooter is improved in the drivable range by 20% with respect to that without regenerative braking. The battery-to-wheel efficiency was also above 70% for both low- and high-speed gears.
[en] Although the meaning of energy efficiency is clear, different definitions exist and important issues relating to its implementation still need to be addressed. It is now recognised that complicating factors – such as complex industrial sites and energy flows, multiple products and fuels, and the influence of production rate on energy efficiency – render it necessary to adopt a structured framework to define and measure energy efficiency more precisely. In this paper, a methodology is proposed to build such a framework. The whole energy system of a site is represented using a single matrix equation, which expresses the relationship between imported energies and energy drivers. The elements of the matrix are the specific energy consumptions of each single process. Mathematical process modelling, through statistical analysis of energy consumption data, is used to quantify the specific energy consumption as a function of the output. The results of this structured approach are relevant for energy benchmarking, budgeting and targeting purposes. Furthermore, this approach is suitable for implementation in an energy management system standard (e.g. EN 16001, ISO 50001) or LCA standard (e.g. ISO 14044). Glass and cast iron melting processes are presented in order to illustrate the application of the method. -- Highlights: ► A structured framework for energy efficiency in industrial processes is proposed. ► Two energy efficiency indicators are revised to take into account a variable output. ► The whole energy system of a factory can be represented by a single matrix equation. ► Mathematical modelling is used to characterise the energy consumption of a process. ► The results are relevant for energy benchmarking, budgeting and energy targeting.
[en] In order to reach the EU: s 20–20–20 primary energy savings target, energy efficiency needs to increase. Previous research on energy use and energy efficiency has focused mainly on the diffusion of energy efficient technologies. The discrepancy between optimal and actual implementation of energy efficient technologies has been illustrated in numerous articles and is often referred to as the energy efficiency gap. However, efficient technologies are not the only ways to increase energy efficiency. Empirical studies have found that a cost-effective way to improve energy efficiency is to combine investments in energy-efficient technologies with continuous energy management practices. By including energy management into an estimated energy efficiency potential this paper introduces an extended energy efficiency gap, mainly in manufacturing industries and the commercial sector. The inclusion of energy management components in future energy policy will play an important role if the energy savings targets for 2020, and later 2050, are to be met in the EU. - Highlights: ► Theoretical contributions examining the role of energy management have been rare. ► Studies have illustrated that adaptation levels of energy management are low. ► By including energy management this paper introduces an extended energy efficiency gap.
[en] Numerical models of transmission-constrained electricity markets are used to inform regulatory decisions. How robust are their results? Three research groups used the same data set for the northwest Europe power market as input for their models. Under competitive conditions, the results coincide, but in the Cournot case, the predicted prices differed significantly. The Cournot equilibria are highly sensitive to assumptions about market design (whether timing of generation and transmission decisions is sequential or integrated) and expectations of generators regarding how their decisions affect transmission prices and fringe generation. These sensitivities are qualitatively similar to those predicted by a simple two-node model. (Author)
[en] In this paper a multi-objective genetic algorithm is used to solve a multi-objective model to optimize the time allocation of domestic loads within a planning period of 36 h, in a smart grid context. The management of controllable domestic loads is aimed at minimizing the electricity bill and the end-user’s dissatisfaction concerning two different aspects: the preferred time slots for load operation and the risk of interruption of the energy supply. The genetic algorithm is similar to the Elitist NSGA-II (Nondominated Sorting Genetic Algorithm II), in which some changes have been introduced to adapt it to the physical characteristics of the load scheduling problem and improve usability of results. The mathematical model explicitly considers economical, technical, quality of service and comfort aspects. Illustrative results are presented and the characteristics of different solutions are analyzed. - Highlights: • A genetic algorithm similar to the NSGA-II is used to solve a multi-objective model. • The optimized time allocation of domestic loads in a smart grid context is achieved. • A variable preference profile for the operation of the managed loads is included. • A safety margin is used to account for the quality of the energy services provided. • A non-dominated front with the solutions in the two-objective space is obtained
[en] This design is intended to revive and utilize fundamental principles of tall buildings into a modern design of an 80-story residential tower in Doha. The main goal in this design is to create an innovative and next generation sustainable tower design specifically for the Middle East by taking advantage of cutting-edge technologies while respecting the traditional way of living that reflects the cultural roots. The design utilizes a vertical exterior cable system which is used as a shading device and contributes significantly to the structural lateral load resistance. -- Highlights: → Linguistically paper has been checked and marked up with blue color as can be seen on marked-up manuscript. → All grammar corrections from reviewers have been made on manuscript with red colors. → On page 6 paragraphs has been added to explain e-QUEST basics. → References are being updated. → Fonts in have been changed.