From the 1st of November 2020, the Greek Power Market is re-organized and operates according to the EU Target Model framework. The previous model of the mandatory pool is succeeded by the design and operation of four successive markets. These are the Derivatives Market (DM), which is a financial market and the three spot markets which are the Day-Ahead Market (DAM), the Intra-Day Market (IDM) and the Balancing Market (BM). The present Thesis is an attempt to efficiently organize and interpret the Spot Markets’ data and present a holistic overview of the market operation and the dynamics under the transitional period of the first three months under the EU Target Model implementation in the Greek Power Market. The analysis of the present study is performed based on real market data, as published from the Hellenic Transmission System Operator (HTSO), which is the ADMIE/IPTO, the Greek Nominated Energy Market Operator (NEMO), which is the Hellenic Energy Exchange (HEnEX) and the ENTSO-e Transparency Platform. The EU Target Model framework is implemented towards the harmonization of market rules and markets operation, across the European Member States, with the provision of the functioning of a single European-wide energy market, the so-called Internal Energy Market (IEM), where one of the main objectives of the IEM is the increase of sustainability, considering high penetration of Renewable Energy Sources (RES) in a European-wide scale.