Electrolysis is too inefficient for in-place energy storage, but economies of scale could in fact make this acceptably efficient for long-distance energy transport; available solar resource varies by more than a factor of three even within the contiguous US. LNG tankers are already a worldwide business, and LNG equipment can be used to transport hydrogen, albeit at much lower energy density. (Generating methane or ammonia from the hydrogen to improve its transportability might be worthwhile.)

Transmission losses in the electric power grid are around 6.5%, but that's because the energy is typically only transmitted a few hundred kilometers; about 4000 km is the longest cost-effective distance for AC power transmission. LNG tankers can travel further than that.