Geological compressed air energy storage as an enabling technology for renewable energy in Ontario,Canada

As renewable resources are increasingly used to provide power to the world’s demand centres, dealing with the intermittent nature of these resources and their affect on the power grid is becoming a significant issue. Compressed air energy storage (CAES) is one technology that is proposed to increase flexibility when integrating renewable energy sources such as wind, solar and tidal generation with the power grid. By creating a storage medium where the energy produced from these sources can be stored and dispatched to the grid as required, a higher penetration of renewable energy generation can be achieved.     

24V/5A太阳能控制器设计

近年来再生能源技术广受重视,而太阳能发电由于有先进的电力电子技术辅助,已成为极具潜力的再生能源之一。文章介绍了太阳能电池的基本原理和伏安特性,提供了一套小24V/5A太阳能控制器的电路。该电路将太阳能电池阵列与蓄电池直接耦合,采用低功耗的单片机P87LPC767作为控制回路的核心,实时测量蓄电池的端电压,通过脉宽调制控制太阳能电池阵列的充电电压,并通过功率管控制蓄电池与负载的通断,实现对蓄电池的放电保护。     

Likelihood of wind energy assisted hydrogen production in three selected stations of Fiji Islands

ABSTRACT

Majority of the people have been paid attention towards renewable and clean sources of energy like wind. Due to the uncertainties related to wind turbines, issues of energy storage are noteworthy. One of the aptest methods of energy storage is the production of hydrogen from the wind. The main aim of this paper is to investigate the potential of wind energy assisted hydrogen production in three selected stations of Fiji Islands using various wind turbines. From the analysis of results and discussion, Vestas V110-2.0 provides acceptable capacity factors among all inspected wind turbines with the highest value of 77.06% for the station at Labasa. Additionally, the highest energy production was from the Vestas V110-2.0 wind turbine with an annual production of 13,501,620?kWh. The conversion system used in this study resulted in a linear relationship between generated wind energy and the amount of hydrogen produced. Therefore, the highest amount of yearly hydrogen production (240.19 ton-H) is related to the largest examined wind turbine, installed in the station at Labasa.     

A general methodology for optimal load management with distributed renewable energy generation and storage in residential housing

In the US, buildings represent around 40% of the primary energy consumption and 74% of the electrical energy consumption [U.S. Department of Energy (DOE). 2012. 2011 Buildings Energy Data Book. Energy Efficiency & Renewable Energy]. Incentives to promote the installation of on-site renewable energy sources have emerged in different states, including net metering programmes. The fast spread of such distributed power generation represents additional challenges for the management of the electricity grid and has led to increased interest in smart control of building loads and demand response programmes. This paper presents a general methodology for assessing opportunities associated with optimal load management in response to evolving utility incentives for residential buildings that employ renewable energy sources and energy storage. An optimal control problem is formulated for manipulating thermostatically controlled domestic loads and energy storage in response to the availability of renewable energy generation and utility net metering incentives. The methodology is demonstrated for a typical American house built in the 1990s and equipped with a single-speed air-to-air heat pump, an electric water heater and photovoltaic (PV) collectors. The additional potential associated with utilizing electrical batteries is also considered. Load matching performance for on-site renewable energy generation is characterized in terms of percentage of the electricity production consumed on-site and the proportion of the demand covered. For the purpose of assessing potential, simulations were performed assuming perfect predictions of the electrical load profiles. The method also allows determination of the optimal size of PV systems for a given net metering programme. Results of the case study showed significant benefits associated with control optimization including an increase of load matching between 3% and 28%, with the improvement dependent on the net metering tariff and available storage capacity. The estimated cost savings for the consumer ranged from 6.4% to 27.5% compared to no optimization with a unitary buy-back ratio, depending on the available storage capacity. Related reduction in CO₂ emissions were between 11% and 46%. Optimal load management of the home thermal systems allowed an increase in the optimal size of the PV system in the range of 13–21%.     

天津滨海新区绿色建筑实践研究

以天津滨海新区可再生能源建筑示范工程为研究对象,介绍了该建筑的围护结构、冷热源及空调系统的选择、太阳能、风能的利用。进行了节能分析,节能效果良好。     

微风电与光伏相结合的分布式发电系统

利用垂直轴微风发电技术,研发了微风电与光伏相结合的分布式发电系统,实现了昼夜不间断发电。垂直轴微风发电比水平轴风力发电系统,具有风力资源利用率高,年发电量多等优点。本文对分布式发电系统不同配置及适用范围进行了论述,为风力资源属于低风速的区域提供了一种可再生能源利用的新技术,尤其适合无电人口地区推广应用。     

Fuzzy logic energy management for a microgrid with storage battery

ABSTRACT

This article presents the development of an energy management system using fuzzy logic applied to a microgrid that combines photovoltaic solar energy, wind energy and a storage system with batteries. The model was developed using LabVIEW software and allows to obtain performance results of the photovoltaic generator, the wind turbine and the battery bank. The energy management system can be controlled in real time to take advantage of existing weather conditions. The results indicate that the fuzzy logic system guarantees the continuous operation of the load through the energy resources of the microgrid. The designed microgrid allows to generate 63,288?kWh/year of photovoltaic solar energy and 40,175?kWh/year of wind energy.     

Comparison of annual energy performances with different ventilation methods for temperature and humidity control

Stratum ventilation has been proposed to accommodate elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling loads, sensible and latent, as well as system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Desiccant dehumidification with and without solar assistance is utilized for the air treatment under displacement ventilation and stratum ventilation, while simple reheating is adopted under mixed ventilation. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following five factors: the reduction in ventilation, dehumidification and transmission loads, prolonged free cooling period and increased the COP of the chillers. For the office, the year-round energy saving is found to be substantial at 20% and 40% without the need for solar energy provision when compared with displacement ventilation and mixing ventilation respectively. For the classroom and retail shop, the year-round energy saving is at about 25% and at least 37% with the aid of solar energy provision when compared with displacement ventilation and mixing ventilation respectively.     

The impact of the integration of renewable energy sources in the electricity price formation: is the Merit-Order Effect occurring in Portugal?

This study investigates the relationship between wholesale electricity price behaviour and the integration of new renewable energy sources in the electricity system in Portugal. The research analyses two different samples, namely: the significant deployment of wind power versus the abrupt increase in the installed capacity of solar photovoltaic. Daily data from 2011 until 2019 and, a SARMAX/EGARCH approach has been conducted to assess the merit-order effect. The main results suggest that electricity production from wind power is decreasing the price of electricity but increasing its volatility. In addition, there is evidence for the leverage effect in electricity price.     

绿色住宅与自然能源利用

本文从绿色住宅与能源利用的角度，介绍了太阳能、风能、地热、生物能等能够从自然界中获得的可再生和重复利用的、洁净的自然能源在住宅建筑中的应用及其发展前景。2001年夏建于日本山口县的实验住宅是绿色住宅的典型代表，它从建筑的材料、技术、造型、设计概念等各个角度进行了创新和探索。用自然能源代替人造的热动力能源是绿色住宅的设计理念之一。     

A solar heating system with annual storage

A heating system is described for a one-family house in Trento, Italy, using solar collectors with buried long-term storage water tanks, made of reinforced concrete and internally water-proofed, assisted by an electrical water—water type heat pump.

The following design parameters are described and evaluated:

a. the annual energy requirement for the house;

b. the solar energy available;

c. the average monthly efficiency of the collectors;

d. the storage tank—ground heat flows, taking storage insulation, water storage temperature and COP to be variable with time;

e. the overall energy balance of the system for the house in question.

The conclusion is that the proposed system can cover the annual energy required for this house with an electrical consumption equal to 20% of the total.     

复合式能源系统在建筑节能方面的应用效果

以某酒店工程的能源系统为例,通过复合式可再生能源供给,满足酒店运行所需的能源。其中,电力源由地面光伏发电、光伏建筑一体化发电、风光互补发电、市政供电及自备发电机组成;冷热源由高温地热水、太阳能集热、水源热泵及常规锅炉组成。通过酒店智能化弱电系统调配各种能源形式,形成先后利用关系,尽量优先利用免费的可再生能源,减少化石能源的利用,最大限度地降低酒店能耗,使该酒店成为实际意义上的节能低碳建筑。     

风光互补发电系统在工程中应用的可行性分析

根据烟台市的风能太阳能资源条件,考虑到风能太阳能发电的互补特性,将风力发电装置和光伏发电装置组合成风光复合发电系统,分析了该复合系统的结构组成及原理,研究结果表明：该系统能够满足负载对用电量的要求,经济性较好,在解决偏远的高速公路路灯以及孤岛等的供电问题上提供了新的解决方式。     

绿色住宅建设中的可再生能源技术

近年绿色建筑和可再生能源技术越来越得到社会和业界的认同,文章从近年来在智能小区建设中常用的太阳能发电、风力发电、太阳导光管照明、太阳能灯具、LED节能灯、太阳能热水、中水回收和雨水收集利用、地源和水源热泵等方面入手,阐述采用可再生能源技术的应用前景及其重要作用.     

Power flow control model of energy storage connected to smart grid in unbalanced conditions: a GSA-technique-based assessment

A gravitational search algorithm (GSA)-based power flow control (PFC) model for energy storage related to smart grid under unbalance conditions is proposed in this paper. Source side and load side power transfer capability is considered to be increased by this proposed algorithm and it offers several conveniences such as the improved predicting capability, degradation in complexity as well as the randomization and so on. The smart grid incorporates the combination of the microgrid (MG) such as renewable energy sources, energy storage devices, grid and load. Here, a renewable energy source of the photovoltaic (PV) system and energy storage of fuel cell (FC) is considered and AC load is utilized. In the proposed method, the controller parameters of the power controller are optimized by the GSA technique based on the variation of active and reactive power of the system. The better power flow under unbalanced load conditions with subject to the minimum power variation is ensured by the optimization process. The proper control signals to the voltage source inverter (VSI) system are generated by this proposed method. Then, the proposed method is implemented using the MATLAB/Simulink platform and a comparison analysis with the existing techniques presents the performance of the proposed method.     

Renewable energy potential and adoption of renewable portfolio standards

Thirty states have adopted renewable portfolio standards (RPSs) that set targets for renewable energy generation by mandating electric power utilities obtain a minimum percentage of their retail load from renewable sources. To date, a number of studies have consistently found that political and economic factors impact RPS adoption. Studies have also examined the impact of renewable energy potential in a state on the probability of RPS adoption, but results have largely been statistically weak and inconclusive. After controlling for political and economic factors, we estimate that a one standard deviation increase in wind potential is associated with an approximately 4.2 percentage point increase in the probability of having an RPS, and a one standard deviation increase in solar potential is associated with a 6.1 percentage point increase in the probability of having an RPS.     

含跨季节储热的多能互补分布式能源系统容量配置优化

为了满足我国对环保及能源的需求,多能互补分布式能源系统成为了分布式能源系统的发展的趋势。文章针对北京地区某办公建筑构建了含跨季节储热的多能互补分布式能源系统,以年总成本最低为目标函数,在满足全年负荷的情况下利用PSO算法(粒子群算法)对该系统中的跨季节储热系统关键设备(储热水箱和基岩储热设备)的容量进行优化,得出了其最佳的容量配置。     

Renewable energy scenario in Telangana

ABSTRACT

This article presents an analysis of the current situation of renewable energy in Telangana, India, and predicts the future of renewable energy resources in the state. In India, maximum power is generated using conventional energy sources such as coal and mineral oil. They highly pollute the atmosphere. If new power plants are to be set up, then the import of highly volatile fossil fuels is inevitable. Though nuclear energy is a good alternative to reduce fossil fuel consumption, it is equally hazardous to human life. Hence, the energy world should think of judicious use of renewable energy resources such as solar, wind, ocean, biomass, and geothermal energy. The R&D activities carried out in India in the past three decades have shown good progress in finding a feasible solution to the problem of searching new renewable energy resources. Telangana is the state committed to use the renewable resources in a better way to fulfil its electrical energy needs. This article also analyses the current energy needs of the state and forecasts energy consumption and production in the future with the aim of finding whether the state can continue on the path of development and augment its renewable energy resources.     

Exploring heterogeneous growth of wind energy across Germany

Expansion of renewable energies in Germany is strongly associated with decentralization of energy provision. In the case of wind energy there are especially strong regional-level spatial, technical, economic, and social ramifications of this energy source. In addition to differing natural conditions and the strong push from the federal feed-in tariffs, policies and initiatives at the state, county, and municipal level need to be considered when explaining the pattern of wind energy expansion across time and space and to improve the coordination of multi-level energy policies. This paper uses panel regressions at the level of German counties from 2001 to 2012 to explore the growth of wind power capacity. Based on the estimates obtained, we then analyze counterfactual scenarios in which factors influenced by the regional (county) level are varied individually. Our focus is on party policy preferences and coalitions on the one hand, and the unemployment rate on the other. While strict causality is difficult to establish, our results reveal heterogeneous incentives between states, within states, and between different county types.     

Efficiency analysis of a solar photovoltaic array coupled with an electrolyser power unit: a case study

Hydrogen as an energy carrier is one of the most potential candidates for clean energy and can be produced by water electrolysis. The use of 10?kW photovoltaic arrays for supplying a 5?kW electrolyser which consists of 10 series-connected electrolyser stacks and a 28% alkaline (KOH) solution electrolyte has been investigated at the Taleghan renewable energies site in Iran. The hydrogen produced by the electrolyser provides energy for the 1?kW polymer electrolyte membrane fuel cell, which meets the load when the solar energy is insufficient. Variations of the solar radiation intensity, the hydrogen production rate, the solar hydrogen efficiency and the overall efficiency of the solar hydrogen energy unit were monitored in detail. The overall energy efficiency was found to range from 0.93% to 5.01%. The obtained results demonstrate the great potential of such a power system for producing and storing energy in a solar-belt country like Iran.