Market clearing price-based energy management of grid-connected renewable energy hubs including flexible sources according to thermal, hydrogen, and compressed air storage systems

Abstract

With the advancement of energy generation and storage technologies, it is expected that the environmentally-friendly integrated units of these elements will have a significant application in the power system so that the energy management of this unit can play a considerable role in improving the technical and economic status of energy networks, besides improving the technical and economic status of its power sources and storage facilities. Thus, the paper concerns the participation of flexible renewable energy hubs equipped with wind farms, bio-waste units, and hydrogen, thermal, and compressed air storage systems in the energy market based on the market clearing price model. Hubs are simultaneously present in both electrical and thermal networks. The bio-waste unit is equipped with combined heat and power technology, producing electrical and thermal energy. The proposed design is in the form of bi-level optimization. Its upper level formulates the maximization of the hub's expected profit, considering the operational constraints of the mentioned resources and storage devices and the hub's flexibility. The market clearing price strategy is included at the lower formulation level, considering minimizing the expected operation cost of electricity and thermal power generation units subject to the optimal power flow equations of electrical and thermal networks. The Karush-Kuhn-Tucker method obtains a single-level formulation for the design. The Unscented Transformation method is used to model uncertainties of load and renewable resources to achieve low computation time and accurate flexibility modeling. The obtained numerical results indicate the proposed design's ability to improve the operation and economic status of energy networks compared with optimal power flow studies (the hub-less network), along with optimal power scheduling of hubs in accordance with improving their flexibility and economic status. So, hydrogen, compressed air, and heat storage devices can reach 100 % flexibility conditions for hubs with wind farms and bio-waste units. Moreover, these storage devices lead to an 11.2 % enhancement in the economic status of the renewable hub. Optimal energy management of renewable hubs based on the storage system has led to a 27 % enhancement in energy network operation status compared to optimal power flow studies.