Analysing the impact of renewables on Iberian wholesale electricity market prices using machine learning techniques

Abstract

<p>The integration of renewable generation sources into wholesale electricity markets is expected to reduce day-ahead marginal prices. This effect has been widely evidenced by previous literature and is commonly referred to as the merit order effect. However, the factors influencing the components of final prices, other than the day-ahead market price, have not been subjected to as much study. Nevertheless, they may prove crucial in understanding the dynamics between the interrelated trading segments in the wholesale electricity market. Furthermore, in the context of the energy transition process, the penetration of intermittent renewable energy sources (mainly wind and solar photovoltaic) and the non-storability of electricity at a large scale may result in increased market balancing needs and costs. The objective of this study was to identify the primary drivers of final wholesale electricity prices in the Iberian electricity market, apart from the day-ahead market price, using machine learning techniques. The results indicate that the share of renewable generation in the day-ahead market is a significant factor influencing both the cost of managing technical constraints, which aims to address network capacity issues, and the cost of managing balancing processes and resolving adjustment issues by the TSO. However, both of these costs can be readily accommodated by the market, as they represent a minimal percentage of the final price. These findings are of interest to both practitioners and regulators, as they provide a better understanding of the functioning of the market and have implications for the restructuring of the market towards a more sustainable and competitive electricity system.</p>