Planning the Development of Electricity Generating Capacity in a One-Zone Electric Power System with a High Share of Renewable Energy Sources

Abstract

The article addresses matters concerned with planning the generating capacity in an electric power system with a high share of renewable energy sources. A stochastic nature of renewable energy sources (RES) makes them very different from conventional power plants. The RES power output depends on weather conditions, due to which some power system operators do not include them in the power balance. This leads to an excess of installed generating capacity in the electric power system and growth of electricity tariffs for consumers. Probabilistic assessments of system adequacy have shown that RES affect the power balance in the power system and do not require to be fully backed up by conventional generation. The article presents the results of calculating the system adequacy for a test IEEE scheme with different share and structure of renewable energy sources. It is shown that the effect of RES on the power balance is governed not only by the annual electricity output, but by the correlation between the RES power output and load curves. A large share of RES in a power system, entails the need to alter the requirements not only for the conventional generating capacities, but also for their structure. The article presents the results of optimizing the composition of generating equipment for different shares of RES in a power system. It has been shown that, if there are no RES in the power system, preference is given to less maneuverable, but cheaper generation units. With increasing the share of RES in the power system, so does the share of more expensive highly maneuverable units. A method of planning the generation capacity development for a single-zone power system is proposed. The value of the generation capacity margin has been determined based on the system adequacy calculation, and the mix of generating capacities is refined proceeding from optimization of the generating units loading.