Environmental Engineering Reference
In-Depth Information
of gravitational potential energy in surface water with respect to an aquifer or
water table below the surface. The proposed system design, operation, neces-
sary technologies and components, and aquifer characteristics are described.
System Description and Operation
The aquifer underground pumped hydroelectric storage system is designed
to store energy in the form of gravitational potential energy in water sepa-
rated between a surface reservoir and a subterranean aquifer. Energy is stored
by pumping water from the underground source into a surface reservoir for
storage. This energy is later recovered by releasing surface-stored water back
to the source through a turbine that generates electricity. Figure 4.2 illus-
trates an aquifer UPHES system. This storage system is most suitable when
used in tandem with variable renewable energy sources such as wind and
solar photovoltaics because the energy storage serves to buffer the variable
output and reliably supply on-demand power for user loads. The main ele-
ments of the aquifer UPHES system include:
• Source of electricity (solar panels, wind turbine, grid)
• Surface reservoir or pond
• Deep, high flow capacity water well
• Integrated motor-pump turbine generator unit
• Electrical center (power electronics, controls, protection)
System
Control
Electronics
User Power
Water Use
H
2
O
Electrical
Feeders
Water
Pump/
Turbine
Electric
Motor/
Generator
FIGURE 4.2
Aquifer UPHES system.
