Concentrated solar power (CSP): the general context and...

Concentrated solar power

(CSP): the general context and

the particle option Gilles Flamant,

Inma Perez

&

Benjamin Grange

CNRS

Gilles.flamant@promes.cnrs.fr

Overview

➢What is Concentrated Solar Energy (or CSP)?

➢State-of-the-art of concentrating solar

technology for power production

➢The future of concentrating solar power plants

➢The particle option for the next generation of

concentrating solar power plants

➢The Next-CSP, H2020 European Project

What is Concentrated

Solar Energy (or CSP)?

A set of mirrors concentrates the sun light to a solar absorber

that heats a heat transfer fluid or a reactive medium,

Concentrating

system

Electricity (CPV)

Electricity (Thermal conversion)

Solar fuels

Process heat

What is concentrated

Solar Energy (or CSP)?

300°C-500°C 500°C-1500°C

Concentrator

Focus

Linear (100 suns)

400-500°C

Point (1000-10 000 suns)

500-2000°C

Fixe

Mobile

Useful Solar Resource

DNI not GHI !

Useful Solar Resource

The useful solar resource for CSP is the Direct Normal Irradiation (DNI).

DNI above 1800-2000 kWh/m2.a is considered as favorable for CSP deployment

State-of-the-art of

concentrating solar

technology for power

production

State of the Art of CSP

technology

✓ The main asset of CSP technology is the massive storage

capacity of heat (industrially up to 3 GWh) that unables up to

14h electricity production at full power after sunset.

✓ Today molten salt thermal energy storage (TES) is the only

industrial option with operating temperature in the range 290-

550°C.

✓ Installed solar plants power ranges from 10 MWe to 250 MWe

NOOR 1, 160 MW,

3h storage full capacity

(Morrocco)

Crescent Dunes, 110 MW,

10h storage full capacity

(USA)

State of the Art of CSP

technology,

Cost of electricity

Decrease of electricity cost

Source: IRENA, Renewable power generation costs (2018)

➢ Decrease of electricity cost similar to

PV 5 years ago

➢ Doubling the installed power capacity

reults in about 30% solar thermal

electricity cost

➢ Cost divided by 2 in 4 years

➢ Last offer at 7.3 c$/kWh with 10h

storage in MENA region

State of the Art of CSP

technology,

Capacity Factor

By comparison, mean capacity factor

of wind and PV without storage are,

Wind: 27%

PV: 18%

(IRENA 2016)

To produce electricity when needed

State of the Art of CSP

technology,

Molten salt TESMolten salt TES and HTF in solar tower

State of the Art of CSP

technology,

Cycle efficiencyCurrent cycle efficiency 38-43%

State of the Art of CSP

technology,

Heat transfer fluidsLimited working temperature range of current liquid HTF

0 200 400 600 800 1000 1200 1400 1600 1800

Thermal Oil

Solar Salt

HITEC

HITEC XL

Na

LBE

T (K)T (°C)

The future of concentrating

solar power plants

The future of CSP

technology

Bottlenecks

Main issues

Source: W Stein & R Buck, Solar Energy (2017), 152, 91

• Cost and efficiency of the

concentrating system

• Working temperature of

the solar receiver / heat

transfer fluid

• Capacity and power of the

TES

• Thermodynamic cycle

efficiency

• Environmental impact

The future of CSP

technology

Thermodynamic cycles

Combined Cycles (hybrid)

Supercritical Cycles

Options to increase cycle efficiency by 25%

The future of CSP

technology

HTF & TES

➢ Heat transfer fluids (HTF)

✓ New high temperature molten salt

✓ High pressure gas

✓ Particles

➢ Thermal energy storage (TES) medium

✓ Liquid

✓ Solid

✓ Phase change

✓ Thermochemical

➢ Thermal energy storage (TES) system

✓ Two-tank

✓ Single tank thermocline

Options

The particle option for the

next generation of

concentrating solar power

plants

The Particle CSP

technology

Principle

The Particle CSP

technology

Particle CSP with combined cycle

Hot Storage

Rotary Valve

Solar Receiver

aeration

FluidizationDispenser

Bucket Elevator

Fluidization

aeration Air Heater/Exchanger

« On Sun » operation

Cold Storage

aeration

Hot pressurized air to Gas Turbine

Principle

Hot Storage

Rotary Valve

Solar Receiver

Dispenser

Bucket Elevator

Fluidization

aeration Air Heater/exchangerCold Storage

« Off Sun » operation

aeration

Hot pressurized air to Gas Turbine

Principle

The Particle CSP

technology

International developmentFalling curtain Centrifugal receiver Fluidized particles in

tubes

SANDIA (USA)KSU (Saudi Arabia)

Univ. Adelaïde (Autralia)

DLR (Germany) PROMES (France)

The Particle CSP

technology

International development

Falling curtain Centrifugal receiver Fluidized particles in

tubes

SANDIA

1 MWth solar receiver

tested (2016)

DLR

500 kWth SR + storage +

heat exchanger (2020)

Solar receiver esting

2018

CNRS-PROMES

3 MWth SR + storage +

heat exchanger + turbine

(2019)

The Next-CSP, H2020 European Project

2016-2020

High Temperature concentrated solar thermal

power plant with particle receiver and direct

thermal storage

The Next-CSP project

Partners

Participant No Participant organisation name Main contribution Country

1 Centre National de la Recherche

Scientifique

Coordination, pilot

testing FR

2 Electricité de France Concept scaling up FR

3 Schlaich Bergermann & Partners Gmbh Heliostat field DE

4 Fundacion IMDEA Energia Integration of high

efficiency cycles SP

5 COnstructions MEcaniques de Schiltigheim-

Strasbourg SA Process design FR

6 Whittaker Engineering Limited Manufacturing and

integration UK

7 European Powder and Process Technology Particle flow behavior BE

8 Katholieke Univerisiteit Leuven Environmental impact BE

9 Institut National Polytechnique de Toulouse Particle flow modeling FR

10 Euronovia Communication,

dissemination FR

The Next-CSP project

Objectives

To improve the reliability and performance of Concentrated

Solar Power (CSP) plants through the development and

integration of a new technology based on the use of high

temperature (750-800°C) particles as heat transfer fluid and

storage medium.

To test innovation for the next generation of CSP plants

with respect to: heat transfer fluids which can be used for

direct thermal energy storage; the solar field and high

temperature receivers allowing for new cycles.

To demonstrate the technology in a relevant environment

(TRL5) and at a significant size (3 MWth).

The Next-CSP project

Some key issues

➢ Solar receiver✓ Working temperature at the limit of alloys mechanical

resistance

✓ Particle flow stability

✓ Heat transfer between the wall and the fluidized particles

➢ Particle-pressurized air heat exchanger✓ Compactness due to low wall-to-air heat exchange

coefficient

➢ Process integration✓ Control of particle circulation in close loop

✓ Weight of the complete system

The Next-CSP project

Pilot loop integration

Concentrated solar beam

The Next-CSP project

Pilot loop integration

Gas turbine

Solar loop

Power cabinet

Solar receiver 3x3 m

Hot storage and

Particle heat exchanger

Cold storage

The Next-CSP project

Small-scale solar tests

Single-tube on-sun testingMean particle diameter: 50 μm

Absorber tube

The Next-CSP project

Small-scale solar tests

Single-tube on-sun testingParticle temperature increase with

1m irradiated length(solar flux density: about 270 kW/m2)

The Next-CSP projectControl of the solar flux

distribution on receiver tubes

To reduce the maximum temperature on metallic walls

No Aiming Strategy Aiming Strategy

Max flux density 650 kW/m²

Max power 3 MW

Max flux density 2.3 MW/m²

Max power 4.2 MW

The Next-CSP projectControl of the solar flux

distribution on receiver tubes

To reduce the maximum temperature on metallic walls

No Aiming Strategy Aiming Strategy

Thank you

Acknowledgements: “This project has received funding from the

European Union’s Horizon 2020 research and innovation programme

under grant agreement No 727762, Next-CSP project."