Life cycle analysis of a Carnot battery based on a Rankine cycle (Pumped thermal energy storage)

: The growth of renewable energy requires flexible, low-cost and efficient electrical storage systems to balance the mismatch between energy supply and demand. The Carnot battery (or Pumped Thermal Energy Storage) converts electric energy to thermal energy with a heat pump (HP) when electricity production is greater than demand; when electricity demand outstrips production, the Carnot battery generates power from a thermal storage (Rankine mode). Classical Carnot batteries architectures do not achieve more than 60% roundtrip electric efficiency. However, innovative architectures, using waste heat recovery (thermally integrated Carnot batteries) are able to reach electrical power production of the power cycle larger than the electrical power consumption of the heat pump (power-to-power-ratio), increasing the value of the technology. In this paper, a comparison with electrochemical batteries is performed. Particularly, a life cycle analysis is performed and shows the environmental benefits of the Carnot battery compared to an electrochemical battery. The aim of this study is to compare the environmental impacts of 5 electric storage systems with a power of 10 kW: Carnot battery based on a reversible heat pump/Rankine cycle with a water heat storage (10 and 25 K lifts), Carnot battery based on a reversible heat pump/RC with a phase change material heat storage (acetamide and naphthol), Li-ion battery. They are described in the inventory section.