Assessment of the market power cost in liberalised electricity markets using SMPI, PMPI, and NMPI indicators

Market power analysis is one of the major issues facing regulators of wholesale electricity markets. The exercise of market power both distorts wholesale price signals and reduces the efficiency of the operation of and investment in the wholesale electricity market. This paper deals with a systematic way for quantifying and visualising market power. The paper first proposes three indicators termed the System Market Power Indicator, SMPI, the Producer Market Power Indicator, PMPI, and the Nodal Market Power Indicator, NMPI. The game theory in applied mathematics and the concept of social welfare in microeconomics are used in formulating of these indicators. The SMPI finds the total cost of exercising market power by generating companies. The contribution of a specific generating company in system market power is calculated using the PMPI. The NMPI finds the contribution of each power system node in the total market power cost. Then after, a colour contour map is used to visualise the exercise of market power and its associated cost. The proposed market power indicators are applied to the modified Garver´s example system to show the promising performance of these indicators.