ste peaking plants

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Innovative Technology Solutions for Sustainability

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SOLAR


STE Peaking Plants: I. Solar thermal energy II. Thermal storage system, flexibility


Introduction: Power Management

Power Generation: Baseload Plants vs. Peaker Plants

STE Peaker Plants: Flexibility

Solana (EE. UU.): The World Largest Parabolic Trough Solar Power Plant



Energy is generated from myriad sources and delivered to very

different consumers

The power sector is a complex system

The grid operator manages, in real-time, generation and demand

considering:

The characteristics of each power plant:

Efficiency

Fuel type

Operation and maintenance

Energy cost

Grid reliability



4

The system operator stacks the power plants’ energy from least to most expensive until the load in met

How is the energy supplied to the grid?

To ensure the most cost-effective energy production

Which is the main goal?



Baseload plants are always running and don’t need to be flexible, like a nuclear power plant

These plants are necessary because there is always some level of energy consumption, even at night

The demand profile changes throughout the day

Flexible peaking units are always available and allow operators maintain grid reliability, peaking plants

Baseload plants Peaking plants

Constant output Flexible capacity

STE plants can incorporate energy storage systems to operate as a

baseload or peaking plant

The grid demands at the same time constant output and flexible capacity. Therefore, we need different types of plants:



Power block Storage system

In order to operate as baseload or peaking plants, STE power plants incorporate:

Appropriate power blocks

Specific storage system


As the grid relies more and more on intermittent

renewable energy resources…

STE Peaking plants: flexibility

Peaking plants provides:

Stability

Flexible capacity

Negligible running cost

CO2 emission free

Long term supply of stable priced peaking electricity



Thanks to its molten salt thermal storage system, Solana can operate as a peaker plant



Gila Bend•

Solana Site

Solana:

Located in Gila Bend, in the Arizona desert

280 MW parabolic trough plant

Its molten salt storage system provides up to six hours of full-load capacity

70,000 households supplied with clean energy

430.000 tons of CO2 emissions eliminated each year



The thermal energy is stored in molten salt insulation system

The sun heats a thermal fluid (HTF) which transfer thermal energy to the molten salts

The storage system provides up to six hours of full-load capacity when there is no sun, in this case at the beginning and at the end of the day

Flexible capacity used to meet load changes before sunrise and

after the sunset

Storage system

Solar field Molten salt storage

system



The thermal storage system allows enough flexibility to face changes in the load demand • An example, June to September

Electricity demand (not scaled) Solar irradiation(not scaled) CSP plant generation

Ou

tpu

t M

W

Hour of day

There is no sun but we keep producing by means of the storage

system



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