Impact assessment of the order types mix in the Greek day-ahead electricity market

The Greek Day-Ahead Electricity Market facilitates a diverse array of order types and offers participants a plethora of choices. While Block Orders are theoretically supported, their accessibility is confined to a subset of market participants so as to ensure the Market Clearing Price formation and the technical feasibility of the resulting Market Schedules. This paper presents a quantitative analysis of the implications of lifting the currently applicable restrictions on the availability of Block Orders in the Greek Day-Ahead Electricity Market, based on past historical data. Clustering techniques are used to convert anonymized past Hourly Hybrid Orders into plausible Block Orders. A market clearing simulator is then used to derive the outcome of the market given the created plausible Block Orders. Simulations are conducted under Coupling and Isolated conditions for three indicative weeks in 2022 and while exploring various scenarios for the specifications of the new Block Orders and the categories of participants who could use them. Assessment metrics encompass Marginal Clearing Price (MCP) statistics, instances of Paradoxically Rejected Block Orders, and Lost Opportunity Cost, shedding light on whether restrictions should be upheld or mitigated.