This chapter introduces the unit commitment model. The fixed (startup and min load) and variable cost of a unit are discussed. Initial conditions, transitions, min up/down times, temperature-dependent startups, startup/shutdown profiles, ramp rates, heat rate curves, and reserves are discussed and represented in a mixed integer linear programming model of unit commitment. The extension of the basic model to uncertainty in the stochastic unit commitment model is discussed. The two-settlement system of day-ahead markets is described. Portfolios followed by nominations are compared to unit-based market models. Exchanges are compared to power pools. The possibility of inexistence of a market clearing price in non-convex market clearing models is discussed. Paradoxically rejected orders in European market models are described. Lost opportunity cost as a metric of deviation from equilibrium is introduced, and related notions such as make-whole payments, uplifts, and potential congestion revenue shortfall are introduced. Convex hull pricing is defined and compared to pricing based on linear relaxations and fixing integer variables. The products of the European electricity market (continuous and block orders) are described. The treatment of European pricing rules in the EUPHEMIA algorithm through a branch-and-cut scheme is discussed.

This chapter analyses the little-known fifth-century Syriac romance Euphemia and the Goth, bringing out its narrative richness to allow it to become part of a wider discourse about identity, violence, and the role of women in the late antique eastern Empire. By employing a structuralist methodology, the story is viewed as containing highly developed and also subtle contrasts, ultimately used by the author to articulate a view of an ideal Edessa. Through the use of distance, dichotomies of barbarian and civilised are set and reinforced with the complimentary distinctions of legitimate and illegitimate violence. These contrasts also allow the primary benefit of Roman rule for Edessa to be made clear, namely the rule of law which ensures justice for vulnerable female-only households against outsiders who attempt to disrupt them, albeit with a strong Edessan identity retained. The analysis finishes by shedding light on the position of women within Edessa at the turn of the fifth century and concludes that options for female-only living were perhaps more positive than for women elsewhere in the Empire.