I'm not sure efficiency matters that much when you have far more energy production capacity than you need but it's concentrated in places and times where you can't use it.
As for costing more: compared to what ? Batteries don't seem like an economically effective option for storing solar energy at massive scale, do they ? And in any case they don't allow the stored energy to be shipped to other locations.
Run some numbers and you find batteries are surprisingly cheap at grid scale. Grid solar is already tied into the grid and does DC>AC conversion anyway as part of it’s 2c/kWh pricing. So, rather than AC>DC>AC>DC you can just use solar panel’s AC power directly. Which means your just adding minimal cabling, batteries, some electronics, and a basic box for weather protection. So, ~100,000$ for 200kWh of storage x ~5,000 cycles that’s 10c/kWh for storage + (2c/kWh solar / 90% efficiency) = ~12.2c/kWh.
Granted that ignoring some real world costs like interest payments, but battery costs are also dropping so it’s a reasonable ballpark. Especially vs a theoretical system that’s never been scaled.
PS: By comparison if your at 50% efficiency to chemical storage and world record 63% thermal efficiency at combustion that’s 2 /.5 /.63 = ~6.3/kWh just for electricity plus the cost of your combined cycle gas turbine and chemical plant.
EDIT: I think for that use case you'll find that a reasonable technology doesn't exist for transporting electrons over that distance (I don't think there are any superconducting transmission lines in actual use) but pipelines have been around for a long time.
