What kind of energy might be saved up for future use?

 Energy cannot be created or destroyed, but it can be saved in various forms.
The term that denotes  the capture of energy produced at one time for use at a later time is energy storage.
Thermal energy might be saved up for future use.
Thermal storage is used for electricity generation by using power from the sun, even when the sun is not shining

The salt in the sea water dehydrated the sailor because her body could not take in the amount to salt in the sea water