Thermal Energy Storage in Solar Thermal Power Plants
Thermal Energy Storage (TES)
Technologies
Applications – Ice cream
cart to Power Gen
Materials -pebbles, Metals,
Molten salt, Paraffin Wax
TES –
Storage of energy in the form
of Latent or Sensible heat of
a material for a later use
WIDE
TES in Power Generation Applications –Concentrated Solar Plants (CSP)
Solar Field
Power BlockTES
Primary UsePower
ApplicationsCSP
Material75%
InstallationsMolten Salt
Parts of a typical Parabolic
Trough CSP with TES
Molten Salt Storage –Big installation base already
Storage – Base load Solar plants possible, Gema Solar 15 hours storage
Molten Salt Storage
2.5 GW ~13 GWh
Electrochemical storage
1.9 GW Small Durations
MOLTEN SALT – Ideal for CSP TES
Thermal Energy Storage (TES) TypesDirect and Indirect
TES
Direct Indirect
• No separate working
fluid for heating &
storage
• Mostly used with
Solar Tower
• E.g.: Solar Electric
Generating Station I,
Gema Solar etc.
• Higher operating
temp upto 5500 c
• Separate working
fluid for heating
(HTF) and storage
(molten salt)
• Mostly used with
Parabolic Trough
• E.g. : Arenales,
Andasol-I, Andasol-II
• Lower operating
temp upto 3800 cRef: NREL,IRENA
Working Principle of Parabolic Trough plant and and need for storage
© Solarmillenium
Cold Tank
Power Block
Heat
ExchangerHeat
Xchngr
Solar Field
380o C
390o C
285o C
385o C
290o C
290o C
Hot Tank
390o C
DD
Parabolic Trough Type Solar Power Plant – Storing Heat in the Molten Salt
© Solarmillenium
Cold Tank
Power Block
Heat
ExchangerHeat
Xchngr
Solar Field
380o C
390o C
290o C
285o C
390o C
290o C
385o CHot Tank
DD
Parabolic Trough Type Solar Power Plant – Recovering Heat from Molten Salt
Cold Tank
Power Block
Heat
ExchangerHeat
Xchngr
Solar Field
380o C
390o C
285o C
390o C
290o C
385o CHot Tank
DD
Molten Salt – Direct storage systems Generally used with Solar Tower - CSP
Solar Tower
Heliostats
Central
Receiver
Hot Tank
Solar Tower - CSP plants Molten Salt – Direct storage systems
Cold Tank
Power Block
Heat
Exchanger
Solar Tower
Upto 560o C
Hot Tank
Plant Configuration
• Technology: Parabolic trough
• Electricity Generation: 150 GWh/yr
• PT Loops : 156
• Turbine Capacity (Gross): 50 MW
• Storage – 7 Hrs Full load
Thermal Storage
• EPC - Flagsol
• Molten Salt - 28,500 tons (BASF)
• Tank Height - 14 m
• Tank diameter – 38.5m
• Temp loss per day – 1o
C
Steag 50 MW CSP Plant with 7 Hrs storageMain Parameters
Molten Salt Indirect storage : Costing Breakup