Capabilities of compressed air energy storage in the economic design of renewable off-grid system to supply electricity and heat costumers and smart charging-based electric vehicles

Abstract

The study presents the sizing of a hybrid renewable islanded system that can feed both electrical and thermal energy simultaneously. The aforementioned energies are generated through the utilization of wind systems and bio-waste units. The integration of combined heat and power technology in the bio-waste unit enables the concurrent generation of electricity and heat power. Electric vehicles consume electric energy, but function based on a smart charging. The study employs compressed air energy storage as a means to bridge the disparity between the patterns of electric power generation and consumption, with the aim of enhancing energy efficiency and reducing planning expenses. Thermal energy storage serves as an intermediary between renewable power and load profiles within the thermal sector. Objective here is find the minimum annual capital and maintenance costs of sources, storages, and power electronic converters. Problem is constrained to operational model of renewable sources, storages, and electric vehicles. The present model prioritizes the utilization of renewable sources for the purpose of supplying electrical and thermal loads. Electric vehicles regulate their active power to minimize the disparity between load and electric production profiles. Storages perform charging and discharging functions to bridge the disparity between power generation and consumption. Strategy incorporates uncertainty related to load, wind speed, bio-waste-derived gas production, and electric vehicles parameters. The study employs a point estimate method to attain a dependable solution. The numerical results indicate that incorporation of compressed air storage in the hybrid system results in a decrease of 7.7 % (12.9 %) in the planning costs relative to system with batteries (hydrogen storage). The proposed design's concurrent provision of electrical and thermal energy leads to an approximately 57 % increasing in planning costs when compared to a system that solely provides electrical energy. The implementation of a smart charging strategy for electric vehicles drop the hybrid system's overall scheduling cost by 3.9 %.