The project aims at developing efficient, eco-sustainable & cost-effective supercritical CO2 (sCO2) for energy storage through Power-to-Heat-to-Power concept, potentially integrated with Concentrated Solar Power (CSP) and Waste Heat Recovery (WHR) application. The project will address small/mid-size sCO2 cycles in the 0.1-10MWe power range, tailoring suitable radial turbomachinery solutions and addressing innovative concepts for the small-scale application (below 1 MW) through bladeless machinery, investigated both at theoretical and experimental levels.
The project undertakes a two-fold approach: system level analysis (eco-design key indicators and thermo-economic performance optimisation) as well as turbomachinery design/optimization and laboratory testing. The cycles will target energy storage services at industrial scale through spinning-reserve capable systems, based on rotating machinery, complementing electrochemical-based devices at an equivalent Round-Trip Efficiency (RTE>75%) and with higher sustainability (no use of rare or dangerous/poisoning raw materials). Furthermore, the project will investigate novel radial turbomachinery specifically conceived for the storage system and, for the first time, the use of innovative bladeless turbomachinery in such sCO2 reversible plants, which may solve integration and cost-effectiveness issues especially for the small power range, tackling known challenges related to the low specific volume of the CO2 in the high-pressure sections.
Three Italian partners (UNIGE, POLIMI, UNIFI), gathering well referenced background and expertise on sCO2 cycles, at system and turbomachinery levels, synergising with all the on-going European H2020 projects on such technology (SCARABEUS, sCO2FLEX, SOLARSCO2OL, CO2OLHEAT, all involving the three partners), and in close cooperation with the US Department of Energy leading the sCO2 technology development worldwide, will join their efforts with technical and strategic advice from industrial players such as Baker-Huges, Florence, leader in sCO2 turbomachinery. Ministero dell'Università e della Ricerca MUR - BANDO 2022 The research activities conceived to achieve such objectives encompass both eco-design and thermo-economic optimisation of plant layouts as well as advanced turbomachinery design and laboratory-scale experimental validation, leveraging on existing facilities and prototypes. In particular a bladeless expander for CO2 and an industrially based CO2 loop test rig will be integrated into a single “ECO-SEARCHERS laboratory” under UNIFI guidance, thus leading to a unique highly added-value outcome of the project. The ECO-SEARCHERS concept promises a highly efficient energy storage solution at industrial scale, compensating the fluctuating photovoltaics and wind, providing spinning reserve and, thus, enabling the future carbon-free power generation at affordable cost and minimum environmental footprint.