Environmental Engineering Reference
In-Depth Information
DID YOU KNOW?
The temperature of the Earth increases, on average, by about 28°C for every
kilometer (80°F for every mile) of depth below the surface for the first several
kilometers down.
D
ry
s
team
P
ower
P
lants
Location-specific dry steam power plants take advantage of subterranean rocks that
are so hot that the water vaporizes on its way up through the production well (see
Figure 6.3). This type of geothermal power plant is able to use steam directly from
the ground to drive the turbine. This is the oldest type of geothermal power plant.
It was first used in Italy in 1904 and is still very effective. These geothermal plants
emit only excess steam and very minor amount of gases (EERE, 2010a).
To transmission
lines
AC
Secondary
coil
Primary
coil
Step-up transformer
Electric
generator
Turbine
Condenser
Ground-
water
pump
Injection
well
Production well
Earth
FIGURE 6.3
Simplified functional diagram of a dry steam geothermal power plant.
