The Greek Day-Ahead Market and Energy Community Participation under Future System Conditions

Abstract

The transition of power systems toward higher shares of renewable energy sources, gradual withdrawal of conventional generation and increasing participation of distributed energy resources has been significantly influencing electricity market outcomes. In Greece, major changes are expected by 2030, including substantial renewable capacity expansion, retirement of thermal generation units and the full interconnection of the island of Crete with the Greek mainland system. These developments are anticipated to highly affect price levels, volatility and overall market dynamics. This paper presents a comparative analysis of outcomes in the Greek day-ahead market under current and projected system conditions and investigates the participation and impact of energy communities. A market simulator capable of reproducing the clearing process is used under two system configurations: 2025 and estimated 2030 conditions. Additionally, the participation of an energy community through stepwise bidding curves under both scenarios is examined. The energy community-market interaction is assessed by introducing the optimized bids into the market simulator and re-clearing the market. The results indicate a notable decline in the average clearing price, from 108.27 €/MWh to 80.95 €/MWh (25.23%) over an examined period of two months, while price variability increases, with the coefficient of variation rising from 39.73% to 59.91%. The expected costs of the energy community during a one-week examination period decrease from -24728.78 € to -20059.79 € (18.88%), demonstrating a measurable improvement in cost efficiency under the projected system conditions.