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.     

Design and simulation of a solar–wind–biogas hybrid system architecture using HOMER in India

The renewable energy sources are accompanied by certain constraints as reliability, availability and continuous generation. In India, biomass is considered as the second best suitable combination with other renewable energy sources. Both solar and wind are undependable renewable energies as they are unpredictable. Now the key to successful renewable energy harvesting lies in the selection of hybrid system architecture for power generation. In rural areas, light is usually unavailable and if it does, it is mostly an incandescent light used for household lighting instead of fluorescent. System reliability, economy and environmental issues are the three major issues for decentralised electrification. So, finding the best suited hybrid system configuration to overcome these constraints is the need of the hour. It is at this stage that HOMER comes into the picture. HOMER, abbreviated name of hybrid optimization model for electric renewable, successfully realises system configuration before its installation and works for on-grid, off-grid and stand-alone systems, which make it useful for rural to urban applications. It simulates and optimises the best suitable solution for a hybrid system and generates reports incorporating all the aspects in designing a system. Here, a typical hybrid system is considered and the implementation of HOMER software has been incorporated.     

基于太阳能热利用的生态建筑能源技术

本文介绍了几种基于太阳能热利用的生态建筑能源技术，涉及太阳能利用的建筑物自然通风，太阳能热水系统，太阳能地板采暖，太阳能热泵空调系统，太阳能热水驱动的吸收和吸附制冷系统。并以上海市生态建筑示范项目为例，介绍了其综合能源利用方案。     

Planning and Governance for Decentralised Energy Assets in Medium-Density Housing: The WGV Gen Y Case Study

The energy needs of most urban populations are serviced with centralised, fossil fuel based generation and transmission infrastructure. However, with the advent of affordable solar and storage technology, this will likely move towards an increasingly hybridised and decentralised model. While many households presently benefit from stand-alone solar photovoltaic systems, in higher density areas this technology is difficult to provide due to the way multi-dwelling buildings are governed. This paper examines a case study for a multi-dwelling, residential building called Gen Y within a bigger innovative development called WGV, in which a planning and governance structure has been developed to provide both financial incentive for the installation of renewable energy in multi-dwelling buildings, as well as to demonstrate how planning can best optimise the behind-the-meter installation and management of solar and battery technology. It suggests the building management company can become a precinct-scale utility.     

A study on environmental impact of nanofluid-based concentrating solar water heating system

The rising cost of fossil fuels and the growing concern for a clean environment have paved the way for adoption of renewable and sustainable sources of energy. Domestic water heating can result from solar energy, a clean and renewable alternative, which can at the same time help to reduce greenhouse gas emissions. This paper examines the potential of the nanofluid-based concentrating solar water heating system (NCSWHS) as an alternative to systems based on fossil fuels. The paper reports a quantitative assessment to assess the potential environmental benefits which could be obtained from NCSWHS if substituted for those using fossil fuels. The analysis reveals that considerable emission reductions (about 2.2 x 10³ kg of CO₂/household/ year) and fuel savings can be achieved if the NCSWHS are adopted.     

Sustainable water-energy nexus in the optimization of the BBC golf-course using renewable energies

ABSTRACT

Water distribution networks and irrigation systems consume high energy quantities that need to be recovered if the water managers want to meet sustainable systems. A sustainability optimization is proposed in this research in order to replace the energy consumption in a golf-course system by renewable solutions joining energy recovery, sustainable urban drainage systems and hybrid solutions (solar panels and wind turbine). Different sustainable approaches were considered in which energy (using PATs), economic and environmental factors were analysed. Both scenarios and analyses showed interesting values related to economic indicators and environmental reductions of CO₂ emissions. The possibility to supply the daily electric consumption in the pumping stations was checked using only renewable systems. Net present value was calculated in different solutions, obtaining positive values as well as the payback period was lower than 6 years. The CO₂ emissions were reduced from 257,000 to 11,500 kgCO₂/year in the most unfavourable scenario.     

Application of solar energy for milk pasteurisation: a comprehensive review for sustainable development

ABSTRACT

Solar energy is available freely. Hence, nowadays people are working on solar energy when compared with conventional sources of energy. Dairy industries require heat, which can be generated by the use of boiler with the aid of wood. Hence, due to increment in global warming, it is necessary to use renewable energy. The primary aim of this review paper is to study various researchers’ work on solar milk pasteurisation system. Hence, it also covers important aspects required for solar pasteurisation like flat plate collector, heat exchanger and solar water heating system.     

现代城市建筑中太阳能技术的应用

在环境问题日益凸现的今天,太阳能作为一种可再生的清洁能源被人们誉为21世纪最有希望的能源.当前太阳能最具潜力的发展领域就是在建筑中的利用.现代城市建筑中太阳能技术的应用已经成为建筑节能领域的技术热点.针对我国目前太阳能在建筑上的利用现状,分析了建筑一体化的太阳能热水系统和太阳能光伏系统.     

Multi-step-ahead forecasting of daily solar radiation components in the Saharan climate

ABSTRACT

Accurate estimation of renewable energy sources plays an important role in their integration into the grid. An unexpected atmospheric change can produce a range of problems related to various solar plant components affecting the electricity generation system. Global solar radiation (GSR) assessment has been increased in the past decade due to its important use in photovoltaic application. In this paper, we propose the use of machine learning-based models for daily global and direct solar radiation forecasting in a semi-arid climate, using a combination set of meteorological parameters on a horizontal surface in the Ghardaïa region. The models are presented and implemented on 3-year measured meteorological data at Applied Research Unit for Renewable Energies (URAER) at Ghardaïa city between 2014 and 2016. The results show that both MLP and RBF models perform well for three-step-ahead forecasting with a slight improvement in MLP models in terms of statistical metrics.     

Predicted versus observed heat consumption of a low energy multifamily complex in Switzerland based on long-term experimental data

The “Solar Complex of Plan-les-Ouates” is a traditional multifamily building with some commercial and administrative areas. It was designed to consume a minimum amount of thermal energy by combining several renewable energy systems (1400 m² of solar roof, buried pipe and exhausted air heat exchangers) with an optimised envelope and electrical equipment. Initially predicted to consume 160 MJ/m² per year of gas, a gas energy use index (per unit heated floor area) of 246 MJ/m² per year was measured. The energy analysis of the building, based on a 3-year period of monitoring, brought up the most relevant points that explain this difference: the real conditions of utilisation (such as the interior temperature) and the real performance of the complete technical system are not taken into account in the theoretical value. Both technical and economical aspects of the renewable energy systems were analysed in detail. An important lesson learned from this experiment is that the energy concept of buildings must be simple and consistent and the complexity of the technical installations must be carefully managed from the design-stage to the exploitation. Detailed monitoring of innovative low-energy buildings is recommended to understand the possible discrepancies between theoretical and real heat consumption and to improve the transfer of new energy technologies to large-scale real constructions.     

Pumps as turbines: an unconventional solution to energy production

In any water system which has excessive available energy (e.g. natural falls, irrigation systems, water supply, sewage or rain systems), the application of a pump instead of a turbine, for energy production, seems to be an alternative solution with easy implementation and considerable equipment cost savings. Micro-hydropower corresponds to a typical renewable energy source without any relevant impacts, and has multiple advantages, as a decentralised, low-cost and reliable form of energy. Unconventional solutions are in the forefront of many developing countries to achieve energy self-sufficiency.     

TRNSYS simulation for solar-assisted liquid desiccant evaporative cooling

ABSTRACT

Recently, desiccant cooling systems are well thought of as a competent method for controlling the water content in the air. A solar flat-plate collector has been used as it decreases the dependency on non-renewable resources. Solar-aided liquid desiccant systems have been used to reduce the dependency of air-conditioning systems on non-renewable sources of energy. Manipal’s humid and searing climate provides certain benefits in setting up such a system. The suggested system has reliability and equipment life and also takes complete advantage of the available solar energy for the renewal of the liquid desiccant. TRNSYS simulation is used to predict the efficiency and feasibility of the system. The temperature and energy-load variations were successfully obtained. An effective simulation was developed whereby the solar air conditioning of a room was indicated.     

Decentralised power generation in rural India

A comparison of a few resource-technology combinations suitable for decentralised power generation in rural areas from the view point of the unit cost of electricity produced has been undertaken. The cost of the extension of grid electricity to rural areas has also been compared with the cost of decentralised power generation using renewable sources of energy. In several situations the decentralised power generation using renewables has been found to be cost effective.     

A preliminary study of wind–solar hybrid systems potential in Jammu and Kashmir

ABSTRACT

This paper deals with the study of wind–solar hybrid systems in the region of Jammu and Kashmir. Due to scarcity of less renewable energy resources in the J&K region, National Institute of Wind Energy, Chennai had installed different wind monitoring stations to measure the wind data at different locations. The survey reveals that four districts (LEH, KARGIL, POONCH and REASI) are suitable for small wind–solar hybrid systems. BIDDA (REASI) and CHUSHUL (LEH) are the two sites for small wind farm development due to the highest wind speed (more than 7?m/s) and power density (more than 400?W/m²) at 100?m agl.     

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.     

福建省大型太阳能热水系统的运行模式与操作管理分析

随着近几年国家对可再生能源在建筑工程中应用补贴政策的推行,福建省太阳能热水系统与建筑一体化工程项目迅速的增加,如何掌握太阳能热水系统的经济运行与科学管理,成为业主的当务之急。太阳能热水系统在不同季节气候条件下生产、储存的热水量是不同的,业主使用热水的运行模式也是不同的,且运行的费用也不同。在全年不同气候条件下,太阳能集热器和空气源热泵热水机组如何各司其责,是管理者必须要掌握的。     

Sensitivity of the total heat loss coefficient determined by the energy signature approach to different time periods and gained energy

In order to identify buildings that have energy saving potential there is a need for further development of robust methods for evaluation of energy performance as well as reliable key energy indicators. To be able to evaluate a large database of buildings, the evaluation has to be founded on available data, since an in-depth analysis of each building would require large measurement efforts in terms of both parameters and time. In practice, data are usually available for consumed energy, water, and so on, namely consumption that the tenants or property holder has to pay for. In order to evaluate the energy saving potential and energy management, interesting key energy indicators are the total heat loss coefficient K_tot (W/K), the indoor temperature (T_i), and the utilisation of the available heat (solar radiation and electricity primarily used for purposes other than heating). The total heat loss coefficient, K_tot, is a measure of the heat lost through the building's envelope, whereas T_i and the gained energy reflect the user's behaviour and efficiency of the control system.In this study, a linear regression approach (energy signature) has been used to analyse data for 2003-2006 for nine fairly new multifamily buildings located in the Stockholm area, Sweden. The buildings are heated by district heating and the electricity used is for household equipment and the buildings’ technical systems. The data consist of monthly energy used for heating and outdoor temperature together with annual water use, and for some buildings data for household electricity are also available. For domestic hot water and electricity, monthly distributions have been assumed based on data from previous studies and energy companies. The impact on K_tot and T_i of the time period and assumed values for the utilised energy are investigated.The results show that the obtained value of K_tot is rather insensitive to the time period and utilised energy if the analysis is limited to October-March, the period of the year when the solar radiation in Sweden yields a minor contribution to heating. The results for the total heat loss coefficient were also compared to the calculations performed in the design stage; it was found that K_tot was on average 20% larger and that the contribution to heating from solar radiation was substantially lower than predicted. For the indoor temperature, however, the utilised energy had a large impact.With access to an estimate of K_tot and T_i, an improved evaluation of the energy performance may be achieved in the Swedish real estate market. At present the measure commonly used, despite the fact that monthly data is available, is the annual use of energy for space heating per square metre of area to let.     

一种新型太阳能集热装置——太阳能多级加热系统

常规能源过度消耗与环境污染正成为我国经济与社会可持续发展的重要制约因素,急需发展环境友好型的可再生能源利用技术.分布式太阳能热利用系统可以有效解决人口非密集地区的能源供给问题.太阳能多级加热系统的研究旨在为以较小的代价提供高品位热能提供新的思路和用能模式.该系统把真空管太阳能集热器、线聚焦型太阳能集热器和点聚焦型太阳能...