Evaluation index system of shared energy storage market towards renewable energy accommodation scenario:A China’s Qinghai province context

With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has the potential to play an essential role in the accommodation of renewable energy generation.However,unified evaluation standards and methods,which can help decision-makers analyze the performance of the SES market,are still not available.In this paper,an evaluation index system of the SES market is designed based on the trading rules of China’s Qinghai province and the structure-conduct-performance(SCP)analytical model.Moreover,the definition and characteristics of the indices,which can show the performance of the SES market from different perspectives,are given.Furthermore,the ideal cases are presented as the evaluation benchmark based on the development expectation of the SES market,and the analytic hierarchy process(AHP)and the technique for order preference by similarity to an ideal solution(TOPSIS)are applied to evaluate the SES market comprehensively.Finally,a case study based on actual data of the SES trading pilot project in Qinghai shows that the evaluation index system can reflect the operation status,existing problems and influencing factors of the SES market.

The Correlation between the Power Quality Indicators and Entropy Production Characteristics of Wind Power+Energy Storage Systems

Power quality improvements help guide and solve the problems of inefficient energy production and unstable power output in wind power systems.The purpose of this paper is mainly to explore the influence of different energy storage batteries on various power quality indicators by adding different energy storage devices to the simulated wind power system,and to explore the correlation between systementropy generation and various indicators,so as to provide a theoretical basis for directly improving power quality by reducing loss.A steady-state experiment was performed by replacing the wind wheel with an electric motor,and the output power qualities of the wind power systemwith andwithout energy storagewere compared and analyzed.Moreover,the improvement effect of different energy storage devices on various indicatorswas obtained.Then,based on the entropy theory,the loss of the internal components of the wind power system generator is simulated and explored by Ansys software.Through the analysis of power quality evaluation indicators,such as current harmonic distortion rate,frequency deviation rate,and voltage fluctuation,the correlation between entropy production and each evaluation indicator was explored to investigate effective methods to improve power quality by reducing entropy production.The results showed that the current harmonic distortion rate,voltage fluctuation,voltage deviation,and system entropy production are positively correlated in the tests and that the power factor is negatively correlated with system entropy production.In the frequency range,the frequency deviationwas not significantly correlated with the systementropy production.

Configuration optimization model of multi-energy distributed generation system

To integrate different renewable energy resources effectively in a microgrid, a configuration optimization model of a multi-energy distributed generation（DG） system and its auxiliary equipment is proposed. The model mainly consists of two parts, the determination of initial configuration schemes according to user preference and the selection of the optimal scheme. The comprehensive evaluation index（CEI）, which is acquired through the analytic hierarchy process（AHP） weight calculation method, is adopted as the evaluation criterion to rank the initial schemes. The optimal scheme is obtained according to the ranking results. The proposed model takes the diversity of different equipment parameters and investment cost into consideration and can give relatively suitable and economical suggestions for system configuration.Additionally, unlike Homer Pro, the proposed model considers the complementation of different renewable energy resources, and thus the rationality of the multi-energy DG system is improved compared with the single evaluation criterion method which only considers the total cost.

Theoretical verification of the rationality of strain energy storage index as rockburst criterion based on linear energy storage law

The rationality of using strain energy storage index(Wet)for evaluating rockburst proneness was theoretically verified based on linear energy storage(LES)law in this study.The LES law is defined as the linear relationship between the elastic strain energy stored inside the solid material and the input strain energy during loading.It is used to determine the elastic strain energy and dissipated strain energy of rock specimens at various loading/unloading stress levels.The results showed that the Wetvalue obtained from experiments was close to the corresponding theoretical one from the LES law.Furthermore,with an increase in the loading/unloading stress level,the ratio of elastic strain energy to dissipated strain energy converged to the peak-strength strain energy storage index(Wp et).This index is stable and can better reflect the relative magnitudes of the stored energy and the dissipated energy of rocks at the whole pre-peak stage than the strain energy storage index.The peak-strength strain energy storage index can replace the conventional strain energy storage index as a new index for evaluating rockburst proneness.

Feed profile analysis of oil palm‐integrated beef cattle farming systems by metabolic energy budgeting and implications for beef production and pastoral system design

Background:Oil palm is a tropical crop with worldwide plantings approaching 20 million ha and large areas in Indonesia,Malaysia and Thailand.The plantations are readily managed as silvopastoral systems incorporating cattle grazing(Oil Palm Silvopastoral System for Cattle,OPSC)but there is a need for analytical tools and data to understand system herbage supply and feed conversion efficiency(FCE).Methods:Metabolic energy budgeting was used to estimate herbage harvested by cattle in three OPSC subsystems,9 and 12 years after oil palm establishment,and FCE of the subsystems was determined.Understorey herbage was also analysed for nutritive value,botanical composition and herbage accumulation within one grazing‐regrowth cycle.Results:The herbage‐harvested estimate was 2.0−2.4 t dry matter(DM)ha^(-1) year^(-1) for 9 year old subsystems and 1.4-1.7 tDMha^(-1) year^(-1) for a 12 year old subsystem.Herbage metabolisable energy(ME)was 8.3−8.5 MJ kg^(-1) DM and crude protein(CP)was 15%-16%DM.FCE values for subsystems ranged from 32 to 94 kg DM kg^(-1) liveweight‐gain.Conclusions:Herbage DM yield is declining,while herbage ME is marginal but CP is adequate.FCE is suboptimal but can be optimised by defining the trajectory of declining herbage production with canopy closure as plantations age and matching stocking rate to herbage supply using a comparativestocking‐rate‐type statistic.

基于Energy-Metrics的训练飞行数据异常识别方法

训练飞行的首要前提就是保证人机安全,通过分析飞行数据来监控和评估飞行质量成为提高安全性和训练质量的手段之一。基于Energy-Metrics(能量度量)的异常飞行数据分析方法可为分析训练飞行安全分析提供帮助。提出了一种在训练飞行进近着陆阶段基于能量度量的异常飞行数据识别方法,首先,通过基于能量度量指标方法为飞行数据生成特征向量,然后,借助具有噪声的基于密度的聚类方法(density-based spatial clustering of applications with noise,DBSCAN)聚类和单类支持向量机(support vector machine,SVM)方法,对能量度量的指标数据特征向量进行飞行异常检测和识别。通过将模拟异常飞行数据隐藏在实际飞行数据中进行飞行数据的检测和识别,证明该方法的异常数据检测成功率为95%以上,且使用不同能量度量指标识别出的异常飞行数据具有高达98%的一致性,证明了该方法在识别异常飞行数据上具有较强的有效性和鲁棒性,为训练飞行回顾性安全分析提供有力的帮助。

A new criterion of coal burst proneness based on the residual elastic energy index

To evaluate the coal burst proneness more precisely,a new energy criterion namely the residual elastic energy index was proposed.This study begins by performing the single-cyclic loading-unloading uniaxial compression tests with five pre-peak unloading stress levels to explore the energy storage characteristics of coal.Five types of coals from different mines were tested,and the instantaneous destruction process of the coal specimens under compression loading was recorded using a high speed camera.The results showed a linear relationship between the elastic strain energy density and input energy density,which confirms the linear energy storage law of coal.Based on this linear energy storage law,the peak elastic strain energy density of each coal specimen was obtained precisely.Subsequently,a new energy criterion of coal burst proneness was established,which was called the residual elastic energy index(defined as the difference between the peak elastic strain energy density and post peak failure energy density).Considering the destruction process and actual failure characteristics of coal specimens,the accuracy of evaluating coal burst proneness based on the residual elastic energy index was examined.The results indicated that the residual elastic energy index enables reliable and precise evaluations of the coal burst proneness.

Development of Wi-Fi Based Home Energy Monitoring System for Green Internet of Things

Green Internet of things （loT） has been heralded as the ＂next big thing＂ waiting to be realized in energy-efficient ubiquitous computing. Green IoT revolves around increased machine-to-machine communications and encompasses energy-efficient wireless embedded sensors and actuators that assist in monitoring and controlling home appliances. Energy efficiency in home applications can be achieved by better monitoring of the specific energy consumption by the appliances. There are many wireless standards that can be adopted for the design of such embedded devices in loT. These communication technologies cater to different requirements and are classified as the short-range and long-range ones. To select the best communication method, this paper surveys various loT communication technologies and discusses the advantages and disadvantages to develop an energy monitoring system. An IoT device based on the Wi-Fi technology system is developed and tested for usage in the home energy monitoring environment. The performance of this system is then evaluated by the measurement of power consumption metrics. In the efficient deep-sleep mode, the system saves up to 0.3 W per cycle with an average power dissipation of less than 0.1 W/s.

Developing and Applying a Ship Operation Energy Efficiency Evaluation Index Using SEEMP: a Case Study of South Korea

The CO2 emission reduction policy of the International Maritime Organization(IMO)recommends that the operation of ships,managed by maritime transport companies,should be energy-efficient.An evaluation method that can determine how successfully a ship implements the energy efficiency plan is proposed in this study.To develop this method,the measures required for energy-efficient ship operations according to the Ship Energy Efficiency Management Plan(SEEMP)operational guidelines were selected.The weights of the selected measures,which indicate how they contribute to the energy-efficient operation of a ship,were derived using a survey based on the analytic hierarchy process(AHP)method.Consequently,using these measures and their weights,a new evaluation method was proposed.This evaluation method was applied to shipping companies in South Korea,and their ship operation energy efficiency indices were derived and compared.This evaluation method will be useful to the government and shipping companies in assessing the energy efficiency of ship operations.

An Index Assessing the Energetic Complementarity in Time between More than Two Energy Resources

Energy complementarity can be a tool for managers to prioritize investments in new power generation ventures. An index for complementarity assessment should allow comparison of complementarities at different sites. This article proposes a new method for the calculation of complementarity index, allowing the comparison two energy resources and also allowing the comparison of more than two energy resources. In addition, the proposed index still allows the use of hourly or daily series and not only maximum or minimum values. Finally, this article also presents a map for the state of Rio Grande do Sul, the southernmost state of Brazil, indicating the energetic complementarity in time between hydropower, wind energy and PV solar energy.

Research on Energy Efficiency Design Index for Sea-going LNG Carriers

This paper describes the characteristics of liquefied natural gas （LNG） carriers briefly. The LNG carrier includes power plant selection, vapor treatment, liquid cargo tank type, etc. Two parameters fuel substitution rate and recovery of boil of gas （BOG） volume to energy efficiency design index （EEDI） formula are added, and EEDI formula of LNG carriers is established based on ship EEDI formula. Then, based on steam turbine propulsion device of LNG carriers, mathematical models of LNG carriers＇ reference line value are established in this paper. By verification, the EEDI formula of LNG carriers described in this paper can provide a reference for LNG carrier EEDI calculation and green shipbuilding.

Energy Optimization of the Fin/Rudder Roll Stabilization System Based on the Multi-objective Genetic Algorithm （MOGA）

Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm （MOGA） method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.

Master-slave wave farm systems based on energy filter with smoothed power output

Wave energy is an important renewable energy source. Previous studies of wave energy conversion(WEC) have focused on the maximum power take-off(PTO) techniques of a single machine. However, there is a lack of research on the energy and power quality of wave farm systems. Owing to the pulsating nature of ocean waves and popular PTO devices, the generated electrical power suffers from severe fluctuations. Existing solutions require extra energy storage and overrated power converters for wave power integration. In this study, we developed a master-slave wave farm system with rotor inertia energy storage; this system delivers self-smoothed power output to the grid and reduces the number of converters. Two control methods based on the moving average filter(MAF) and energy filter(EF) are proposed to smooth the output power of wave farms. RTDS simulations show that the proposed systems and control methods facilitate simple and smooth grid integration of wave energy.

Construction of Comprehensive Development Index and Analysis on the Development Trend of Solar Energy Industry

As a strategic emerging industry, solar energy industry has been wished to ease the energy crisis and stimulate economic growth. In order to judge the development of the industry objectively, this paper constructs the index system of China’s solar energy industrial development from three dimensions of micro enterprise, medium industry and macroeconomic. This paper simultaneously takes 27 specific indicators, 54 listed companies and 10206 data from 2010 to 2016 as an example to calculate the industrial development index. The result reveals that with the implementation of the support policies playing a positive role in the development of China’s solar energy industry, the solar industry has steadily improved. Solar energy industry in our country is under the support of national support policies and its technological innovation capability is relatively active. However, the moderate investment and financing activities and inadequate enterprise operational capacity, to some extent, alleviate the development of the solar energy industry. The above shows that the solar energy industrial development index and its evaluation methods can help people to accurately grasp the development trend of the solar energy industry and accurately identify the development of advantages and disadvantages.

A New Approach to the Calculation of Work Index and the Potential Energy of a Particulate Material

The work index Wi was defined by F. Bond as the specific energy (kWh/ton) required to reduce a particulate material from infinite grain size to 100 microns. The calculation is based on the size-energy relationship e1,2=C.(1/x2n–1/x1n ) , which for n = 0.5, x1 = ∞ and x2 =100, by definition gives e∞, 100 = Wi and consequently C=10Wi. In theory, for a given material the value found for Wi.should be constant regardless of the measured sizes x1 and x2 used to calculate the constant C by measuring the energy e. In practice this is not so due to the fact that n ≠ 0.5 and many correction factors have been proposed to overcome this inadequacy experienced by accepting n= 0.5. The present paper proposes a simple way to calculate the appropriate exponent n using conventional grinding procedures. The same calculation can be used to calculate the true value of Wi and attribute a potential energy state to a material at any size.

Development of a drill energy utilization index for aiding selection of drill machines in surface mines

Drill machines used in surface mines, particularly in coal, is characterized by a very poor utilization （around 40%） and low availability （around 60%）. The main purpose of this study is to develop a drill selec- tion methodology and simultaneously a performance evaluation technique based on drill cuttings produced and drilling rate achieved. In all 28 blast drilled through were investigated. The drilling was accomplished by 5 different drill machines of Ingersoll-Rand and Revathi working in coal mines of Sonepur Bazari （SECL） and Block-II （BCCL）. The drills are Rotary and Rotary Percussive type using tri- cone rock roller bits. Drill cuttings were collected and sieve analysis was done in the laboratory. Using Rosin Ramler Diagram, coarseness index （CI）, mean chip size （d）, specific-st trace area （SSA） and charac- teristic particle size distribution curves for all the holes drilled were plotted. The predictor equation for drill penetration rate established through multiple regressions was found to have a very good correlation with an index of determination of 0.85. A comparative analysis of particle size distribution curves was used to evaluate the drill efficiency. The suggested approach utilises the area under the curve, after the point of trend reversal and brittleness ratio of the respective bench to arrive at drill energy utilization index （DEUI）, for mapping of drill machine to bench, The developed DEU1 can aid in selecting or mapping a right machine to right bench for achieving higher penetration rate and utilizations.

Study on correlativity among some seismological prediction indexes related to earthquake frequency or energy

Correlation among various seismological prediction indexes related to earthquake frequency N or energy E for describing seismicity changes is studied by seismic data of 11 seismic zones (areas) in the Sichuan-Yunnan region. A statistical test for correlativity shows that seismicity indexes obtained from transformation of earthquake frequency N or energy E have correlation to a certain extent while they are used to describe seismicity changes. If the transformation is linear in all cases, the correlation coefficient is equal to 1. The smaller the transformation deviation from linearity, the bigger the correlation coefficient is.

Distributed Air-Conditioning Energy Management System within the Smart Grid Context

-Air-conditioning （AC） systems are the major energy consumption units in residential and commercial buildings. In the context of smart grid, optimizing AC operations leads to substantial saving in energy consumption, reducing the consumer＇s bill and contributing to the environment by minimizing carbon emissions from generating stations. This paper presents a distributed AC energy management system for buildings by using networked master-slaves controller architecture. The proposed system was designed, simulated, and experimentally tested by using real AC units in a students＇ residence hall. Based on the students＇ class schedules, several operational scenarios were implemented and tested. The proposed system implementation leads to a 40% to 60% saving of the consumed energy by the tested units. The same energy management scheme can be applied and implemented in other commercial and residential buildings.

Estimates of energy expenditure using the RT3 accelerometer in patients with systemic lupus erythematosus

This study aimed to characterize energy expenditure patterns using the triaxial accelerometer and to identify the association of energy expenditure with clinical parameters in patients with systemic lupus erythematosus (SLE). Estimates of energy expenditures represented by total activity calorie (TA), physical activity calorie (PA), total activity calorie per body weight (TABW), and physical activity calorie per body weight (PABW) of 49 female SLE patients were assessed using the RT3 triaxial accelerometer (StayHealthy, Monrovia, CA) in a sevenday period. SLE patients in the highest body mass index (BMI) tertile showed significantly lower values of TABW compared to those in the lowest tertile, while SLE patients in the lowest TABW tertile showed significantly higher body weight, waist circumference, BMI, SLE disease activity index (SLEDAI), dosage of prednisone, and blood pressure. There was a high prevalence of metabolic syndrome and SLE patients with metabolic syndrome showed significantly lower TABW. In addition, both TABW and PABW significantly but negatively correlated with SLEDAI. In conclusion, the RT3 accelerometer is suitable for evaluating total and physical activity-related energy expenditure in patients with SLE. TABW measured by the triaxial accelerometer is inversely related with body weight status and disease activity in SLE patients. This suggests that estimates of energy expenditure by the tri-axial accelerometer may be applied in the management of SLE.

Case Study:Promoting Sustainable Energy Greenhouse Heating Systems to Small-Scale Local Farms

Biomass energy generated from livestock manure,other agricultural by-products and food waste can be an affordable greenhouse-heating energy source for those seeking lower energy costs.Appalachian State University,North Carolina(NC),USA,has built a 6.1 m×9.1 m greenhouse,called the“Nexus”to test the integrated sustainable energy heating system for growing season extension with less energy cost.This is done by using on-farm biomass resources/wastes such as agricultural waste and wood chips to produce energy coupled with solar water heating to store and supplement required thermal inputs.Growing season extension with heated greenhouses increases the availability of local food throughout the year,expands available markets and increases farmers’profits.Nexus includes an above ground 5,680-L water storage tank and an aquaculture pond.It is supported by a small-scale pyrolysis system,an anaerobic digestion system,solar thermal and compost heating.The preliminary result showed that compared to a conventional space heating system,about 30%of energy was saved to keep the greenhouse temperature available for growing by radiation from the water storage tank.The main purpose of this study was to test the proposed greenhouse heating systems developed at Nexus by implementing pilot systems on two local farms.Pyrolysis and solar thermal system in conjunction with heat storage and delivery system for each farm were built and tested in order to demonstrate how to reduce greenhouse energy use.This paper describes the results of the case study,which showed significant energy savings that can promote the resource-limited farmers’interest.