Possibilities and Perspectives of the Wind and Solar Power Plants Application in Combined Energy Systems

The energy industry of the world is currently experiencing a period of intensive development and use of renewable energy sources, primarily wind and solar power plants in the structure of combined energy systems. This process develops despite the fact that these sources, by their physical nature, are unable to provide either a stable frequency of the energy generated by them, or a guaranteed power. In addition, the vast majority of the costs that wind and solar power plants cause by their operation are covered by external fast-acting sources, the energy of which has a very high price. One of the ways to solve these problems is the use of energy storage systems. This article proposes a mathematical model for the study of frequency and power regulation processes in energy systems with distributed generation, which allows to estimate under what conditions distributed generation becomes self-sufficient. The novelty of the proposed model lies in the possibility of determining the cost indicators of energy based on instantaneous data of its power, which significantly improves the results of applying the symbolic method. Model calculations were performed for two variants of the operation of the energy system with wind generators of 1500 MW installed power. The model was verified by calculating the frequency deviation during the studied time interval, which demonstrates the ability of the model to accurately reproduce the dynamics of the frequency stabilization process. At the end, the calculation of the energy-economic indicators of a real combined power system with a powerful sub-system of wind generation and a battery-type energy storage system is given, which proves the competitiveness of self-sufficient renewable source power plants.