How is electricity produced?
Water is injected into the geothermal
reservoir via an injection well, and
flows through the geothermal reservoir
using the network of fractures. As the
water passes through the reservoir it
is rapidly heated - this is known as the
underground heat exchanger. Under
pressure the heated water is returned
to the surface via a production well.
On the surface Binary Cycle or Flash
Steam power plants can be used
to generate electricity from the
Binary Cycle power plants use a surface
heat exchanger to extract heat. The
heat exchanger is a series of pipes
which allow the transfer of heat from
the geothermal water to another
liquid, without the liquids ever mixing.
The second liquid is allowed to boil,
producing high-pressure steam that is
used to drive the electricity turbines.
Once the heat has been removed
from the geothermal water it can be
re-injected into the reservoir to be
heated and used again.
Flash Steam power plants allow the
geothermal water to turn to steam,
and the steam is directly used to turn
electricity turbines. Any remaining water
is re-injected into the reservoir for re-use.