Energy alternatives: the Indian perspective

India's immense geography provides her with a variety of ambient energy resources. This paper examines the non-conventional energy sources and their possible future in India. While the non-conventional energy sources include geothermal energy, waves, tides and ocean thermal energy in addition to direct solar radiation, the emphasis in the paper is on solar, biomass and wind energy applications. Conventional energy sources including coal, oil, gas and nuclear energy are not going to be adequate and the alternative sources discussed are not going to be capable of fully replacing the above sources in any foreseeable future. While these alternative sources are likely to be only a partial substitute and not a total replacement, their contribution can usually be well above 50 per cent of the total energy needs. The energy profile of the country has also been discussed.     

Improved hydrological projections and reservoir management in the Upper Indus Basin under the changing climate

The availability of water resources plays an important role for the economy of a country. The nexus of energy‐food‐water are interlinked and of particular importance in the uncertain environment of developing countries. In Pakistan, agriculture contributes 25% to the gross domestic product. The Indus River contributes 44% of the available water to irrigation of crops and the ecosystem, and currently produces 5,112 MW electricity, with the potential to produce 38,602 MW electricity. This makes it important to investigate the status of water availability in the Upper Indus Basin under existing emission scenarios. In this study, the future availability of water is projected for the Indus River under the A2, B2, RCP4.5 and RCP8.5 emission scenarios. A meta‐analysis has been conducted to present a combined picture by combining the results from the emission scenarios. Our meta‐analysis shows higher confidence in RCPs projections. The results show that suffcient water will be available in the Indus River that will meet the demands of water in future but there will be scarcity of water in some months under each scenario. However, by proper management and optimum utilisation of the available water, this scarcity can be resolved.     

Optimisation of solar and wind energy systems: a survey

In the last decade, the penetration of renewable energy sources (RESs) for energy generation has increased. Because of their several technical and environmental benefits, solar and wind energy systems are the major RESs that are being increasingly employed for different aims. In solar and wind energy systems, there are a variety of optimisation problems which are non-linear and non-convex in nature. Study of the literature shows that among the meta-heuristic techniques, genetic algorithm (GA) and particle swarm optimisation (PSO) are highly used to solve different optimisation problems of solar and wind energy systems. The main goal of this paper is to review different applications of GA and PSO in solar and wind energy systems. This review will enable the researchers to study the present status of different solar and wind optimisation problems and plan for future investigations.     

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.     

可再生能源在绿色建筑中的复合应用技术

可再生能源技术是实现绿色建筑的可靠保障之一。然而单一的可再生能源由于其本身的缺陷,应用有其局限性。本文提出了可再生能源在暖通空调中复合应用的思想。着重介绍了三种可再生能源的复合利用形式:太阳能和自然风、土壤能和太阳能以及自然风和蒸发冷却技术的复合利用。     

Feasibility analysis of distributed solar electricity penetration in cement manufacturing plants

Industrial manufacturing units like cement and steel are benefited little by solar electricity. This paper presents feasibility of application of solar electricity in cement manufacturing plants in a distributed manner. Distributed solar PV systems without battery have been simulated using HOMER Pro micro grid design software to see the effects on net present cost (NPC), levelised cost of energy (COE), pollutant emissions, coal consumption and cost of cement production. The daily solar radiation ranges from 3.79 to 6.71?kWh/m²/day and the total distributed load supplied by solar electricity is 8876.4?kWh/day which is 0.82% of overall plant load. The results show that proposed system reduces pollutant emissions by almost 23% with an increase of NPC by 3.075% and COE by 0.6436% only. It saves 709,139?kg coal per year with 0.6437% increase in cement production cost. Proposed system will be beneficial economically too when PV prices come down in future.     

The Inner Mongolia Autonomous Region: A major role in China's renewable energy future

Because the IMAR is China's second largest coal producing region and the entire nation depends on over half of its energy demand from coal, the issue about more coal becoming part of the energy supply is of grave concern to the region and central government. In addition to that, China has been building more structures that demand more and more energy. The options for energy in China are to dig for more coal, discover oil and gas or import these fossil fuels. However, consideration for the environment and climate change along with concern for national security has forced China to consider a non-fossil fuel option: conservation and efficiency along with renewable energy power generation.IMAR has vast regions and areas where wind and solar have already been installed. By 2009, almost 1 GW of renewable energy systems had been installed and operating in all of China. Most of the energy was generated by hydroelectricity, though wind power - a rapidly technology in China- accounted for almost one fourth. More GWs of energy are possible along with geothermal and related renewable power sources such as the run of river and bio-mass. Major energy companies in the region are now advancing and exploring these renewable energy options along with western companies as joint ventures that create new industries, create jobs and lessen both IMAR and China's dependency on fossil fuels.     

智能建筑系统集成与工程设计

讨论了智能建筑系统集成,包括其网络互联、通信协议,以及工程实施等,并对工程设计中的若干具体问题提出了相应的建议。     

Studies on solar power satellites with down-converter solar cells

The Solar Power Satellite (SPS) is a renewable energy technology potentially capable of meeting the projected worldwide energy demand for future generations. Some general aspects of SPSs are discussed in this paper. It was calculated that a power output of 97.24?MW (almost double the power produced by a typical natural gas plant) could be generated using a theoretical system with solar photovoltaics with a total optimised dimension of 0.18?km². Among the potential problems discussed are the possible effect of microwaves on living organisms and the high capital costs involved in building and launching the satellite into a suitable orbit.     

Wind energy potential,development and current trends in India: a review

The demand for electricity is increasing day by day in the world. In a developing country such as India, the electricity demand is increasing at a terrifying rate as compared to the meagre supply. At present, the Indian power industry is mostly based on fossil fuel. Nowadays, wind energy has emerged as a renewable energy source which has a huge power generation capacity. India is one of the leading producers of wind energy but has the potential to generate even more energy through it. This paper presents a review of wind energy resources, its potential, development and current trends in India. A wind turbine can be easily set up as it takes less space as compared to other power stations and can be easily located at places such as deserts, remote areas, offshore, etc.     

当今世界太阳能热水器的发展状况

世界能源统计报告资料显示,常规能源可供人类使用的时间非常短暂,能源安全形势非常严峻.为了解决这一问题,从20世纪70年代开始,科学家就开始研究可再生能源的利用,太阳能以其经济、安全等优点,成为可再生能源开发中的重要组成部分.从论述全球常规能源现状,国际太阳能以及中国太阳能热水器的发展现状着手,指出世界太阳能市场正面临一个难得的发展机遇,我们应该把握机遇,不断提高太阳能产品质量及技术水平,使我国真正成为太阳能热利用的强国.     

Modular multi-level converter-based DFIG wind power system with MMC-STATCOM

ABSTRACT

Transmission and distribution conversion operation, voltage, current magnitude variation and time-to-time power flow change through grid are the major issues in power system. Variable wind energy system is more popular for power generation through conventional converters and hence harmonic reduction is very less in these converters. In this paper, 9?MW modular multi-level converter-based DFIG wind energy power system parameters are compared with 9?MW DFIG systems using conventional converter. DFIG is operated in four mode condition with proper back-to-back power electronic converters and controllers. In power electronics, the modular multi-level converters are more advanced for reducing transients, peak response oscillations and improving the efficiency of the system. A five-level MMC has been applied in back-to-back converter with phase disposition (PD) PWM technique for DFIG wind system of the same rotor side controller and grid side controller. A conventional converter-based DFIG wind energy system is replaced with five-level MMC-based system with level shift PD-PWM technique. The impact of MMC on DFIG wind energy system is reduced voltage and current harmonics fast settling time compared to conventional converter-based DFIG system. The above MMC DFIG power system voltage is balanced at fault condition with MMC-STATCOM.     

Structural stability of concrete wind turbines and solar chimney towers exposed to dynamic wind action

Apart from burning classical fossil resources or generating nuclear power, alternatives have been developed, like the classical ways to capture energy from wind, water and sun, or the innovative solar chimney concept.The paper presents some structural aspects of classical wind energy turbines, like their high-cycle dynamic loading and reaction as well as their fatigue behaviour. Actual research results concerning pre-stressed concrete tower constructions for wind turbines will be focused on. For the solar chimney concept the structural challenges concerning wind action, eigenfrequencies, stiffening and shape optimization with special focus on the inlet guide vanes will be discussed. Both classical wind turbines and the innovative solar chimney concept may successfully contribute to the future energy supply in Southern Africa.     

Technische Entwicklung und Anwendungen im Kraftwerksbau

Technique development and field of application for power station units. In numerous countries, power stations for electrical power production are build since decades. Multitude possible energy source like water, wind, solar, nuclear, gas, oil, refuse etc. will be use for energy production, but this article shows the technique development and field of application for conventional coal fired power station units. The development of power stations shows, that the electrical power output for conventional coal fired power stations has reached 1100 MW. This based on the further development of the process engineering design and utilization of new high‐tensile steel for boiler and piping. Central power stations out of a catalogue – partly build in USA – are not usual for the European market. Power stations are individual developed with regard to end customer, location, kind of coal and optimized for the efficiency. The most important requirements for modern steam generators are: low pollutant emissions, high efficiency, flexible operation, high availability, easy maintenance.     

可再生能源发展对我国能源结构的影响

本文从目前国际可再生能源发展环境、我国可再生能源发展政策法规、可再生能源发展的壁垒等几个方面分析了可再生能源的发展情况,指出由于在建筑、交通、工业等领域能源的消耗特点和一次能源的有限性,我国的能源结构必然会从以煤炭为主的一次能源高度集中的现状,发展到较多、分散型的可再生能源与一次能源并存的状态,最后发展到可再生能源占主导地位。     

日本《风力发电设备支持物构造设计指针及解说》(2010)简介

风力发电近年来发展迅猛,前景光明.目前,中国已成为世界风能应用第一大国.但是,风力发电机组面临抗风、抗震等结构安全性问题,而业界对此关注不足.日本是多台风、多地震国家,在这方面做了大量研究工作,并编制了《风力发电设备支持物构造设计指针及解说》(2010).本文简要介绍了该规范的编制背景和主要内容,以资借鉴.     

Potential for a Danish power system using wind energy generators,solar cells and storage

Some overall properties of a power system in a northern climate based mainly upon renewable energy are studied.

The power system consists of wind energy generators and solar cells in combination with a storage system and a back-up system. The type of power plants constituting the back-up system are not specified. The back-up system could be used to generate power only when the rest of the system is unable to cover the load. The predicted performance of the solar/wind power system is calculated on the basis of hourly meteorological data measured in Denmark during the years 1959 to 1972.

It has been established from this data that to maximise the fraction of annual load covered by solar and wind energy the ratio of solar to wind production capacity is approximately 40% solar to 60% wind. With only small changes in the energy provision, however, the ratio could be varied between 20:80 and 60:40.

The saving in energy resulting from provision of various storage capacities has been studied. This saving will be negligible if less than half of the annual load is covered by the solar/wind power system. For a solar/wind power system with a production capacity of 1.25 times the annual load the marginal energy saving effect of a storage system is reduced by a factor of 10 when the storage capacity is increased from 0 to 24 hours. The marginal costs of producing the electricity rise steeply when more than about 80–90% of the load is to be covered on the basis of renewable energy. Finally it is shown that when 80% of the load is covered by renewable energy the storage capacity should not exceed 40 hours.     

Uncertainty in estimating renewable energy utilisation potential: a case of solar thermal power generation in India

Estimation of renewable energy utilisation potential is important for identification of niche areas and prioritisation amongst different options. However, large variation in the potential estimates has been observed in different studies for the same renewable energy technology. This study is an attempt to analyse such a variation in the estimated potential for solar thermal power generation in India. From the analysis of three studies, it is found that the values of input parameters and the assumptions made substantially affect the estimated potential. The estimates of the utilisation potential depend upon the categories of wastelands selected, the chosen values of threshold DNI and wind speed as well as the criteria used for allocating suitable wastelands between solar photo-voltaic (PV) and thermal power generation. It is therefore critically important that reported values of renewable energy utilisation potential be interpreted and used with full cognisance of assumptions made and input parameters used in estimation.     

Analysis and design of a robust controller for a grid-connected photovoltaic power plant

ABSTRACT

Application of renewable energy systems has a drastic impact on the present power system. In particular, solar photovoltaic power generation is expanding exponentially. Hence, in this article analysis and design of a 1 Mega Watt (1?MW) solar power plant has been modelled. The obtained power is given as an input to the voltage source converter, which contently regulates the active and reactive power by controlling the pulse width modulation signals. In this article, robust control schemes were discussed to support the required active and reactive power. Further, a detailed analysis has been presented at various fault conditions and the results are explored.