This is right. For grid connected storage, two things matter: 10-year total cost, and durability. At least a 30-year design life. (Well, reliability matters to

This is right. For grid connected storage, two things matter: 10-year total cost, and durability. At least a 30-year design life. (Well, reliability matters too: that 's implicit.) Volume and mass are just whatever they are. They don't matter.