Money quote: Using the worst assumption in each case, solar cells with storage emit 631 gCO2e/kWh vs 337 gCO2/kWh for normal hydrocarbon fuel in spain.
Important takeaway: A solar cell embodies a huge amount of energy, yet can be shipped. Make solar cells in places with lots of clean energy and ship them elsewhere.
True, but that's only half the story. The other half is that high-load and low solar-insolation means batteries degrade faster / require larger batteries and requires more panels, respectively. Even batteries built with clean energy isn't necessarily always the best application versus taking energy from the grid (especially a nuclear powered grid).
Shipping is negligible and when compared by energy per tonne per km, can be up to almost 100x better than road, so going 200km by road can compare to going nearly 20000km by sea in some cases.
Putting everything in one place could get savings from many factors, but transport doesn't appear to be that major compared to the others.
Important takeaway: A solar cell embodies a huge amount of energy, yet can be shipped. Make solar cells in places with lots of clean energy and ship them elsewhere.