This challenge, as it is officially called by the FWEE, is a nice and easy one and can be completed in one day. You will need to do a lot of driving depending on your location. You will get to visit astounding dams creating hydro-electric power.
Stamp your passport online after visiting each site. You have to visit at least 5 of the sites to claim the reward. See map below. At the FWEE website, you get the list with all the caches at the different dams.