OPTIMIZED SCHEDULING OF HYBRID ENERGY SYSTEM

Abstract

Energy plays a very crucial part in our day to day life. Today the major sources which contributes to meet the energy needs of the world are conventional sources like, coal, gas etc. But the world energy scenario is such that conventional energy sources are depleting at a very fast rate and there is a urgent need to search for the alternate energy sources with the aim of sustainable development. Though, the alternate energy sources are known since a long time yet their contribution in the total energy mix is very low. This is due to the problems of intermittency and high cost associated with these resources. Nevertheless, efforts are being made to reduce these and shift the generation to alternate sources. The major advantages that renewable energy system have are eco-friendly and availability of resources at the site, reducing the cost of transportation. In this study work is done on a Hybrid Renewable Energy System (HRES). Hybrid Renewable Energy System combines one or more than one renewable energy sources with a - non-renewable one, in order to increase the reliability of the system. The combination of resources gives a way to tackle with the intermittent nature. The basic aim of the work here is optimum load despatch or scheduling of the designed HRES system. The considered system aims to meet the basic demand of a rural area i.e. Electrical, Mechanical and Thermal demand with a combination of solar, wind, biomass and micro-hydro. Apart from the renewable resources, a diesel set is also provided in order to increase the reliability of the system. The system is provided with the facility of energy conversion from thermal to mechanical energy and mechanical to electrical energy, whenever in excess. The electrical energy if more than the demand at any time is firstly stored in the battery and if excess still appears is provided to dump in the dump load. The problem of hourly resource assessment is also taken up in this work. In this the main consideration was to predict solar and wind hourly profile as biomass and hydro resource generally tend to remain constant during the course of a day. The prediction of solar and wind is done using the characteristic distribution of these resources. The distribution followed by solar radiation is beta and that by wind speed is weibull. The parameters of the distribution are calculated using the mean and standard deviation. This helps to predict the solar and wind values for each hour of a day. Moreover. Monte-Carlo simulation have been used in order to deal with the unpredictable nature of the wind speed and solar radiations. Thus, a band range of values are obtained for each variable and in each hour. The next thing after resource assessment is the problem formulation, which is based on the Profit Maximization of an Independent power producer and is a linear problem. The problem is hourly optimization and consists a total of 357 variables with a total of 51 inequality constraints and 72 equality constraints. The optimization solution of the problem has been performed using MATLAB. The optimization is carried out using the most popular optimization technique found in the literature i.e. Linear Programming Technique. Though, the problem is applied on a particular area but can prove very beneficial for other such type of rural areas. This study did coin the optimal scheduling for the HRES system but still have a lot of scope for research in future.