Integration of renewable energy driven systems with a pumped thermal energy storage for providing dispatchable electricity
mario petrolleseSecondo
;giorgio cauUltimo
2023-01-01
Abstract
Current energy transition requires renewable and sustainable energy sources to be integrated within feasible energy storage schemes. This integration can potentially lead to significant benefits, such as the dispatchability of the produced sustainable electric energy. In this work, an innovative energy system based on three integrated Renewable Energy driven systems with a Pumped Thermal Energy Storage (PTES) section to provide green dispatchable electricity is proposed and analysed. The integration scheme includes a mix of photovoltaic installation (PV) and wind turbines (WT) farm electrically connected to the user and, in case of electrical surplus, to a Brayton-based PTES system. The latter is also thermally integrated with a Concentrated Solar Thermal (CST) plant, specifically, with a central receiver tower system, as the high temperatures that usually characterize the hot reservoir perfectly match those reached in gas-phase solar receivers. The energy stored in the PTES system is subsequently converted into electricity during deficit periods, minimizing the grid support. An optimization problem is therefore formulated and solved by means of GAMS software with the aim of finding the optimal design of the proposed integrated systems in terms of number of WT, number of PV strings, collecting area of the CST systems and PTES storage capacity. An objective function based on the maximization of the system performance is defined and tested and its effects on the optimal plant design are analysed for different percentage of allowable unmet energy. It is found that a 4% of allowed unmet power provides a good compromise between unmet power and energy lost / system efficiency. The optimal configuration presents a 1 MW wind turbine, a 3 MW PV plant and a CST section with a heliostats field of about 7600 m2. Finally, the sensitivity analysis carried out on the PTES efficiency and maximum storage capacity highlights the impact of these parameters especially on the energy lost in CST section.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.