An additional insight from this analysis is the break-even battery efficiency. For our sce-nario with a demand charge of 6 USD/kW and an energy charge of 0.10 USD/kWh, we obtain no savings on operating costs if the round-trip battery or storage system efficiency falls below 74%. In practice, the break-even round-trip efficiency is expected to be even higher as there are additional costs to operate the battery such as thermal management systems, general maintenance, self-discharge losses, and more. This limits the potential of re-purposing endof-life batteries from automotive applications, as they have efficiencies of 75 -83% which further decrease upon use. This result also indicates that several other electrochemical stationary energy storage solutions such as nickel-metal-hydride, nickel-cadmium, redox flow, and lead acid batteries do not meet the round-trip efficiency requirements. The same applies to thermochemical storage systems which have even lower round-trip efficiencies in the range of 30-60%. 100 Sodium-ion battery is an emerging technology that has the potential to be a good fit for the charging station application. It features similar round-trip efficiencies as lithium-ion batteries, but benefits from lower material costs as sodium is considerably more abundant than lithium. It has the potential to reach prices of 40 USD/kWh based on targets set by CATL. 101 However, this technology still lacks commercialization and will only be a viable solution in the coming years.