ACHIEVING 45% MICRO GAS TURBINE EFFICIENCY THROUGH HYBRIDIZATION WITH ORGANIC RANKINE CYCLES

Abstract

The demand for affordable, secure, and sustainable energy storage solutions has grown significantly with the increasing focus on decarbonization and the adoption of renewable energy sources (RES). Power-to-Power (P2P) energy storage systems (ESS) have emerged as a promising solution, utilizing excess electricity from RES to produce hydrogen for future power generation. This document presents a study on increasing the round-trip efficiency of P2P ESS by improving the electric efficiency of micro gas turbines (mGT) and integrating waste heat to power (WHP) technology. The research investigates the potential of mGTs as prime movers in P2P ESS, aiming to break the 45% electric efficiency barrier that would make them competitive with other alternatives like internal combustion engines (ICE) and fuel cells (FC). Increasing the nominal electric efficiency of mGTs would lead to significant reductions in hydrogen consumption, system footprint, and overall capital expenditure. Thus, this research focuses on increasing the electrical efficiency of the mGT by proposing a hybridization between the recuperative Brayton cycle and bottoming organic Rankine cycles, reaching higher than 45% electrical efficiencies in a hybrid configuration. An exhaustive comparison of the main ORC systems hybridized with the recuperative Brayton cycles is presented. The results reveal that hybridizing an intercoolingrecuperative Brayton cycle with a simple recuperated ORC has the potential to increase electrical efficiency to 46%. The work also presents a sensitivity analysis to assess how the design parameters influence the performance of the hybrid thermodynamic cycle.