yeah i just tested that, you need to do shift before ordering the hydro and then press the hotkey once again (quite fast) to get the energy storage.
if you do hydro then shift you can't get energy storage by pressing once more on the hotkey. Even if you do this fast.
though i've always played with energy storage on same hotkey than pgen (from a previous ui mod), and it never occur that i would build e storage after hydro. Just saying, not like making a point here.