Pump storage hydroelectricity involves pumping water from a lower reservoir to an upper reservoir during off-peak hours using surplus grid power. The stored water is then released through turbines to generators during peak hours to produce electricity and meet higher demand. It helps balance the electricity load by absorbing excess power during low demand and releasing it during high demand periods. The largest pump storage plant is located in Bath County, Virginia and has an installed capacity of 3003MW from 6 turbines. It provides load balancing and frequency regulation services on the power grid.

1. Pump Storage HydroelectricityPump Storage Hydroelectricity
Debojyoti Mukherjee
EE 3rd
year 44
Debojyoti Mukherjee
EE 3rd
year 44

2. What is Hydroelectric power?What is Hydroelectric power?

Water is stored at an
elevation. Then it is
released at a fixed rate, the
potential energy stored in
the water is used to drive a
turbine which works as a
prime-mover for the
generator.

It is most popular
renewable source of
energy.

It now supplies 17.5% of
world’s electricity needs.

In india it supplies 14.35%
i.e 42,783 MW of
electricity.

Water is stored at an
elevation. Then it is
released at a fixed rate, the
potential energy stored in
the water is used to drive a
turbine which works as a
prime-mover for the
generator.

It is most popular
renewable source of
energy.

It now supplies 17.5% of
world’s electricity needs.

In india it supplies 14.35%
i.e 42,783 MW of
electricity.

3. What is Energy Recapturing?What is Energy Recapturing?

At day time most
factories, offices and
households are
demanding electricity and
this is called on-peak
period.

since industrial electricity
rates are higher than the
domestic rates it is also
high-profit or high-cost
electricity.

Industry should not be
hampered due to power
shortage thats why
electricity during on-peak
is high-valued.

4. Pump Storage SchemePump Storage Scheme

It is a type of hydroelectric
plant but in this case water is
not naturally present at the
elevation, instead water is
pumped using Low-cost off-
peak electric power from the
grid or onsite steam plant.

It is a storage mechaism used
for high power demand at
peak hours, the water is
released just like an regular
hydroelectric plant and the
excess power demand is
fulfilled.

It is a type of hydroelectric
plant but in this case water is
not naturally present at the
elevation, instead water is
pumped using Low-cost off-
peak electric power from the
grid or onsite steam plant.

It is a storage mechaism used
for high power demand at
peak hours, the water is
released just like an regular
hydroelectric plant and the
excess power demand is
fulfilled.

5. Pump Storage Scheme cont...Pump Storage Scheme cont...
Helps to balance the flow of power across transmission networks by
absorbing excess when electricity demand is low and releasing it when
demand increases.
Helps to balance the flow of power across transmission networks by
absorbing excess when electricity demand is low and releasing it when
demand increases.

6. Number of machinesNumber of machines

Four unit scheme: separate generator,
motor, pump and turbine is used and they
operate independently. The cost is
generally more. Hence not commonly
employed

Three unit scheme: The generator and
motor are same devices and in tandem
with separate turbine and pump. This
sceme is more commonly used.

Two unit scheme: Same device work as
both turbine and pump and another device
serves as both generator and motor. This
method is gaining popularity.

7. Recirculation type PSSRecirculation type PSS
● The water volume in upper and
lower reservoirs are same, the
same water is used in pumping and
generation process.
● Seepage and evaporation can be
taken care by small inflows in upper
or lower reservoir.
● Power is generated only during on-
peak period.
● This scheme is more feasible where
potential head is already present.

8. Mixed PSSMixed PSS
● A conventional hydroelectric plant and a
pure recirculation pump strorage is
combinely used in this method.
● The upper reservoir is too large and
supplies water in most time of the year
when sufficient water is available.
● During off-peak period it can be used as
conventional plant.
● In dry seasons plant is used for pump
storage scheme only.

9. Advantages of PSSAdvantages of PSS
AdvantagesAdvantages
Converts low-cost,
Low-value off-peak energy
To high-value, high-cost,
on-peak energy
Converts low-cost,
Low-value off-peak energy
To high-value, high-cost,
on-peak energy
Load levellingLoad levelling
Can strore large amount
Of
energy
Can strore large amount
Of
energy
Eco-friendlyEco-friendly
Can Work as a
Synchronus
condenser
Can Work as a
Synchronus
condenser
Quick start-up time
(<5min)
Quick start-up time
(<5min)

10. Operating problemsOperating problems

Cannot be used again until it is again
pumped up.

Powerhouse locations must be such that
the pump operates under submerged
conditions. This is called cavitation.

Periodic reversal in water flow causes
runner craking due to fatigue.

Trash racks vibrate violantly during
pumping operations.

Flow during pumping lift the machine
vertically causing huge tensile stress in
the bearings and guide vanes.

11. ➔ Capacity: 3003MW
➔ Turbines: 6x500MW, Francis type
➔ Comissioning date: Dec, 1985
➔ Water Flow:
➔ Pumping: 801m3
/sec
➔ Generating: 852m3
/sec
➔ Upper reservoir: 1.07km2
, 32m
fluctuating water level
➔ Lower reservoir: 2.25km2
, 18m
fluctuating water level
Largest PSH plant-Bath CountyLargest PSH plant-Bath County

12. PSH Plants in IndiaPSH Plants in India

13. SourceSource
1. Pump Storage Hydro Power Plant-Mayadhar Swain
Electrical India (Nov, 2013)
2.Wikipedia-https://en.wikipedia.org/wiki/Pumped-
storage_hydroelectricity
3.Dominion-https://www.dom.com/corporate/what-we-
do/electricity/generation/hydro-power-stations/bath-county-
pumped-storage-station