The Greek Regulatory Authority for Energy (RAE), in view of the initiation of the new wholesale electricity market on January 1st 2009 as a Day-Ahead mandatory pool, undertook the design and implementation of a simulator for the market. The simulator consists of several interacting modules representing all key market operations and dynamics including day-ahead scheduling, natural gas system constraints, unplanned variability of loads and available capacity driven either by uncertain stochastic outcomes or deliberate participant schedule deviations, real time dispatch, and financial settlement of day ahead and real-time schedule differences. The modules are integrated into one software package. The intended use of the simulator is to elaborate on and allow RAE to investigate the impact of participant decision strategies on market outcomes. The ultimate purpose is to evaluate the effectiveness of Market Rules, whether existing or contemplated, in providing incentives for competitive behaviour and in discouraging gaming and market manipulation. In this paper the simulator is used to analyze market design aspects and rules concerning the co-optimization of energy and reserves in the Day-Ahead energy market and the efficiency of the imbalance settlement procedure compared to real-time pricing.
