Water is stored
in a high reservoir
Water is released
when electricity
demand is high
Water flows through
a turbine, generating
electricity for the grid
Lake or
loch
Head height
Greater height
improves efficiency
Water pumped
back to reservoir
when electricity
demand is low
Water is stored
in a high reservoir
Water is released
when electricity
demand is high
Water flows through
a turbine, generating
electricity for the grid
Lake or
loch
Head height
Greater height
improves efficiency
Water pumped
back to reservoir
when electricity
demand is low
Water is stored
in a high reservoir
Water is released
when electricity
demand is high
Water flows through
a turbine, generating
electricity for the grid
Lake or
loch
Head height
Greater height
improves efficiency
Water pumped
back to reservoir
when electricity
demand is low
Water is stored
in a high reservoir
Water is released
when electricity
demand is high
Water flows through a turbine,
generating electricity for the grid
Head height
Greater height
improves efficiency
Water pumped back to reservoir
when electricity demand is low
Lake or
loch