Energy can't be moved as easily as food

It can be moved much easier. Electricity moves at the speed of light (through an ideal conductor).

If you generate electricity in Iowa you can't easily sell it to California.

Within the Eastern and Western grids, power generated anywhere can be easily sold anywhere else within the respective grids. For example, the Intermountain Power Project in Utah has historically supplied a significant portion of electricity to Southern California.

Moving power between these grids is a little more complicated --- only because the grids are not synchronized. But this too is technically possible and could be made easier if there was more demand to do so.