how it works

• Water stored at a hydroelectric dam has potential energy.

  When it runs through the dam this turns to kinetic energy.

  The kinetic energy of the moving water is used to generate electricity.

  A) potential energy

  B) kinetic energy

  C) electricity

  
• Water flows down through the penstock.

  It turns the blades of turbines as it passes through them.

  The spinning turbines turn generators that create electricity.

  The electricity passes through transformers so it can travel long distances efficiently.

  The water cycle returns water to the dam,

  making hydroelectric power renewable and reliable.

  A) transformer

  B) generator

  C) turbines

  D) penstock

  
• The water cycle returns water to the dam,

  making hydroelectric power renewable and reliable.

  A) rain

  B) clouds

  C) water

  D) evaporates

  E) river

  
• A dam’s job is to 

  block the flow of a water source,

  
• As the water has nowhere to go, a large amount of water pressure builds up.

  this generates potential energy as the water, if released, will rush down through the dam.
• As the water has nowhere to go, a large amount of water pressure builds up. 


  this generates potential energy as the water, if released, will rush down through the dam.

  
• When it is released,

  the water travels from the reservoir through a tunnel in the dam called the penstock

  
• Because the water is now moving, it changes from having potential energy to

   kinetic energy.

  
• This kinetic energy turns the turbines quickly, which then turn the 

   generators.

  
• When the generators turn, they convert the kinetic energy into 

  electrical energy.

  
• The transformers then adjust the electricity's voltage so that it can

  travel long distances through power lines without losing lots of energy. 

  
• Other transformers then reduce the voltage to a safer level 


  before the electricity enters our homes, schools or workplaces.

  
• hydroelectricity comes from

  moving water