Determination of the optimum spinning reserve requirements in power systems including renewable energy sources

In operation of electric power systems, it is essential to determine the optimum amount of reserve requirements for the security of electricity supply both economic and technical view. The increasing penetration of renewable energy sources to power systems over the last decades creates some risks due to the variability and uncertainty of output power of these sources. Uncertainty defines the errors in estimating meteorological measurements such as solar radiation, temperature and wind speed; variability defines the fluctuating of the output of wind and solar energy systems unlike fossil fueled power plants. The balancing of energy supply and demand have been need to novel approaches because of these two problems. As a result, the determination of reserve requirements, which is ever difficult, has become more complicated with penetration of large-scale renewables to power systems. In this study, first of all energy markets are mentioned, the effect of renewable energy sources on determining of reserve requirement is discussed, the methodologies used in reserve calculations and approaches are explained. Secondly, the different definitions of operation reserves in USA, Europe and our country are given. The development of energy market around the world and in our country is summarized and the operations of Day Ahead Market, Intra-Day Market and Balancing Market are explained. In case study, the optimum reserve requirements are calculated in a 24 bus updated version of The Institute of Electrical and Electronics Engineers Reliability Test System (IEEE RTS) using different methods. The power of wind and solar scenarios are defined using statistical analysis of given data. Deterministic and stochastic solutions are compared for different load profiles which are given based on seasons for IEEE RTS. The results of the study show that it is essential to use stochastic methods which can be added scenarios for renewables and contingencies in power systems including large scale wind and solar energy systems. Finally maximum capacity of wind and solar power are calculated considering optimum reserve capacity for minimum operating cost.