I don't think you want to use our current battery tech to store large amounts of energy. I'd go with hydrogen or perhaps synthetic methane instead, because we can reuse much of the existing natural gas infrastructure.
Hydrogen is a potential solution but it’s very difficult to store and transport.
It's a little more difficult to store and transport than methane, yes. If that turns out to be a deal breaker, you can always upgrade the hydrogen to methane using atmospheric CO2. You lose a bit of efficiency, but perhaps that's cheaper than upgrading the storage and transport infrastructure.
These steps reduce the efficiency of the fuel.
Yes, I said that. Efficiency doesn't matter, only cost matters. They correlate, but they're not the same.