Impact of Energy and Climate Policies on Electricity Generation - Analysis based on Large-scale Unit Commitment Modeling

Electricity generation systems in Europe are undergoing dramatic changes, largely driven by changing energy and climate policies. In this dissertation, three evolutions are dealt with in particular: (1) the deployment of intermittent renewables in electricity systems such as wind and solar photovoltaics, (2) the integration of electricity markets and (3) the mitigation of CO2 emissions from the electricity sector. The focus of this dissertation is on the technical and cost-related aspects of electricity generation systems, taking an operational viewpoint (i.e., no investment decisions are studied in this work). The dissertation presents several case studies inspired by realistic and large-scale electricity systems. Concerning the deployment of intermittent renewables, the impact of variable renewable generation on cycling of conventional power plants is studied, as well as the impact of remote renewables—such as offshore wind—on grid congestions. Regarding the integration of electricity markets, this dissertation investigates the benefits of integrating reserve markets and discusses the flow-based market coupling implemented in Central Western European day-ahead markets. Finally, concerning CO2 emission abatement in the electricity sector, the impact of a CO2 emission price on the generation of electricity is studied, together with the policy interaction between the European emission trading system and the deployment of renewables. A unit commitment model has been developed and is used in this dissertation. This model, referred to as the LUSYM model, is a state-of-the-art deterministic unit commitment model, formulated as a tight and compact mixed-integer program and able to solve large-scale electricity systems within reasonable run times. The model includes power plant constraints, renewables curtailment, load curtailment, storage units, transmission grid constraints and reserve constraints. Benchmarking simulations show that the LUSYM model is competitive or outperforms commercial unit commitment packages in terms of optimality of simulation results and/or run times. All the case studies presented in this dissertation, providing qualitative and quantitative insights, indicate that electricity systems are indeed evolving in the direction envisioned by policy makers (at least when it comes to the deployment of renewables, the integration of electricity markets and the reduction of CO2 emissions). However, this dissertation also demonstrates that changing energy and climate policies pose new challenges to electricity systems, such as maintaining the system balance with a large share of intermittent generation. In this respect, unit commitment modeling plays an important role in evaluating policies and their impact on electricity generation systems, in order to develop effective and efficient policies.status: publishe