How might a renewable energy source become nonrenewable?

Non-renewable energy source : those source which can't be replenished .These will run out if not used judiciously. These includes : Fossil fuel ,coal , petroleum , natural gas

Renewable energy : Those source which are naturally replenished and can't run out in human life -time . Example : Sunlight , wind , rain etc.

Explanation:

Theoretically it is not possible that a renewable energy source become a non-renewable source.

Now , take the example of Water. Water is a renewable energy source because of water cycle. Due to water cycle the amount of water lost from earth surface comes back to it in the form of Rain. Hence water should not run out .  

But if we consider Underground water . It is only 1.7 % of the total earth water .

Now ,by 2020 many Populated cities run out of underground water . You may ask , How is it possible since water is renewable?

The reason is because of construction , overgrazing , agriculture The rainwater can't penetrate deep in earth . So amount of under ground water is decreased.

Overpopulation is also another reason. It result into more consumption of underground water .

So , at this point we can say that underground water has become non - renewable.

Hence there are possibility (very low) that a particular renewable source become non-renewable because of drastic human - activities like : Over -consumption of sources , overgrazing (these leads to climate change which in turn disturb the natural cyclic processes. Hence degrade the renewable sources)