Heat can be stored purely physically in the form of sensible heat (temperature difference), latent heat (phase change energy) and through the use of reversible chemical reactions (reaction energy).

The specific latent heat of a substance is the amount of energy needed to change the state of 1 kg of the substance without changing its temperature. It usually takes more energy to boil a ...

Note the flat lines on the curve where the latent heat must be overcome to change phase. Unlike batteries or capacitors, phase change materials don’t store energy as electricity, but heat.

Now, to figure how much energy is discharged when all that rain is produced, you have to use the so-called "latent heat of condensation." When water vapor cools sufficiently, it condenses into ...