Renewable energy sources offering flexibility through electricity markets

All over the world, penetration of renewable energy sources in power systems has been increasing, creating new challenges in electricity markets and for operation and management of power systems, since power production from these resources is by nature uncertain and variable. New methods and tools to support optimal decisionmaking under uncertainty in the electricity markets and power system operation, for both producers and system operators, are developed in this thesis. The existing market architecture integrates, to some extent, the participation of renewables by allowing these producers to offer in the day-ahead market and to correct for potential energy imbalances in the intraday market and ultimately in the balancing market. However, the design and rules of electricity markets do not support the transition from conventional generation to renewable energy sources as recently sought by many governments. Renewable energy sources are characterized by their uncertain and variable production that limits the current operation and management tools of the power system. Nevertheless, recent developments of renewable energy technologies enable these resources to provide, to some extent, ancillary services. Hence, the opening
of the reserve market for renewables participation is crucial for the integration of 100% renewables into the system. New business models will emerge from these challenges, while renewable energy producers will require appropriate decision-making support tools to jointly offer in both
energy and reserve markets. In this context, the main contribution of this thesis is the design and development of optimal offering strategies for the joint participation of renewables in the energy and reserve markets. Two distinct control policies for the splitting of available wind power in energy and reserve are considered. Different methods and optimization tools are developed based on these control policies,
considering distinct goals of producers’ participation in energy and reserve markets. Nonetheless, these tools allow renewable producers to move forward in the decisionmaking process of future energy and reserve markets. Towards a power system based on distributed energy resources, mainly comprising renewable sources, new operation and management of distribution systems needs to be thought of. In fact, the existing passive distribution grid management does not provide the flexibility to deal with uncertainty and intermittency of distributed energy resources. In this context, a major contribution of this work is the design and development of a preventive distribution grid management that allows distribution system operators to contract flexibility (ahead in time) from distributed energy resources to assist in the management and operation of the grid in case of congestion and voltage problems. Such a proposed methodology opens the door to other methods in this timely research problem. Finally, new costs for this operation and management of the network will arise, requiring new cost allocation methods to split these costs between the energy resources that induce such congestion and voltage problems. To deal with this concern, one can
propose new cost allocation methods that divide the costs of operation and management of the distribution network among all network users (generators and consumers) promoting equity, fairness, impartiality and equality. The hybrid methodology combines different costs (fixed, network usage/congestion and losses) covering all the gaps of each conventional cost allocation method.