Checked out the SHIELD fight again to get some idea of how he ranked.
Electro seemed capable of absorbing energy in general to some extent, he just sucked it up right out of the hover crafts and from SHIELD's hover-carrier, despite them apparently having shields, referenced but not really shown, at least not on that youtube clip.
Also seemed capable of blocking/possibly absorbing the energy blasts from their ship.
Interestingly enough at one point we see a couple missiles launched at him from one hover craft but we never see what happens.....
Certainly could be a problem for Superman.