Batteries have the serious downsides that (1) they cost more than almost anything else, and (2) cost is per kWh stored, rather than just kW in and per kW out. F

Batteries have the serious downsides that (1) they cost more than almost anything else, and (2) cost is per kWh stored, rather than just kW in and per kW out. Flow batteries could mitigate this some where electrolyte is cheap. Synthetic fuels have the enormous advantages that (1) tankage is super-cheap (negligible cost per kWh), (2) tankage is easily transported, (3) there is unlimited market for them, (4) you can burn them in existing combined-cycle turbines. These advantages easly overwhelm low round-trip efficiency, which is anyway relentlessly increasing. We will be shipping hydrogen or ammonia from the tropics to Baltic states in winter. It is hard to imagine any viable green alternative, aside from reliance on fallible transmission lines.