Imagine you live in a town next to a fast-moving river. The town builds a big dam to control the water. 

Do you think that moving water could be used to make electricity? How might that help the town? What could be some downsides?

Hydropower is an adaptable, low-emission energy source, but why do you think we might not be able to build many dams in the future? 

Hydropower is flexible and long-lasting, yet its share of global electricity is expected to shrink. Explain possible reasons why.