Before revision:  Finally, the numerical and empirical analysis suggests that the high cycle cost for battery  is still the main barrier for grid-connected battery systems , and the flexibility offered by such systems would be currently the most promising comparative advantage for this novel technology.
After revision:  Finally, the numerical and empirical analysis suggests that the high cycle cost for battery systems is still the main barrier for grid-connected battery systems , and the flexibility offered by such systems would be currently the most promising comparative advantage for this novel technology.