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CSPConcentrating Solar (Thermal) Power

Technologies and Challenges

Manuel RomeroIMDEA EnergyMóstoles, Spainhttp://www.energy.imdea.org

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CSPConcentrating Solar (Thermal) Power

Technologies and Challenges

Manuel RomeroIMDEA EnergyMóstoles, Spainhttp://www.energy.imdea.org

Concentrating Solar ThermalElectricity for tomorrow…. and

much more

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Index

1. CSP= STE (Solar Thermal Electricity)2. Dispatchable solar electricity: Storage3. Market deployment4. Technology challenges5. CSP beyond STE SFC6. Conclusions

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Solar Thermal Power Plants: Ambition of bulk power production

Solar time

From storage Solar direct

supply

To storage

From storage

Fixed power

Ther

mal

ene

rgy

to tu

rbin

e

Solar time

Fossilbackup Solar direct

supply

Fossil backup

Fixed power

Ther

mal

ener

gyto

turb

ine

OPTICAL CONCENTRATOROPTICAL CONCENTRATOR

RECEIVERRECEIVER

FOSSIL BACKUPFOSSIL BACKUP

HEAT HEAT STORAGESTORAGE

COLD POINTCOLD POINT

HOT HOT POINTPOINT

WW

OPTICAL CONCENTRATOROPTICAL CONCENTRATOROPTICAL CONCENTRATOROPTICAL CONCENTRATOR

RECEIVERRECEIVERRECEIVERRECEIVER

FOSSIL BACKUPFOSSIL BACKUPFOSSIL BACKUPFOSSIL BACKUP

HEAT HEAT STORAGESTORAGE

HEAT HEAT STORAGESTORAGE

COLD POINTCOLD POINTCOLD POINTCOLD POINT

HOT HOT POINTPOINTHOT HOT

POINTPOINT

WWWW

Slide 5Maricopa Solar by SES, USA

Archimede Priolo Italy by ENEA

LFC in the Liddell Power plant by Areva, Australia

PS10 solar tower by Abengoa, Spain

Solar Thermal Power Plants: Point focus (3D) Linear Focus (2D)

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Optimization of solar concentration systems

• Stagnation temperature:

0_ dT

d rectot

abs

ambabsT

TTCarnot

*

)(**44

ConcTT ambabs

rec

Carnotrecrectot *_

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-Spain: 1,000 GW grid-connected by end 2011, 2,500 by 2013 and 5,000 by 2020.-US: 4,500 MW under construction. Foreseen 8,000 MW by 2020.-First projects in Italy, Morocco, Egypt, Algeria, United Emirates-New markets in India, China, Australia and South Africa

CSP early markets: Spain and US

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USA: Distribution by technologies

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CSP: Examples of commercial projects in Spain

Villarrobledo, Cuenca (Infinia)

PS10 and PS20 (Abengoa Solar)

La Dehesa, Badajoz (SAMCA)

Gemasolar (Torresol)

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La Risca, Alvarado

Acciona/ Mitsubishi Corp (Alvarado, Badajoz)

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Acciona/ Mitsubishi Corp (Majadas, Cáceres)

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Acciona/ Mitsubishi Corp (Palma del Rio 1 y 2)

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Extresol 1 and 2

Two storage tanks (ø= 36 m, h=14 m)• Storage capacity (h): 7,5h @ 50 MW• Molten salts: 28,000 Metric Tons/• Melting temperature: 221º C• Working range: 291º C - 384º C

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Andasol 1 and 2

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Manchasol 1 y 2

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Renovables SAMCA, S.A. (La Florida, Badajoz)

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Renovables SAMCA, S.A. (La Dehesa, Badajoz)

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PER 2011-2020: Renewable electricity generation in Spain by 2020CSP & PV = 7.4% (about 30,000 GWh/year)

Coal

Oil & non-renewable wastes

Hydropower by pumping Hydropower

w/o pumping

Solar thermal electricity

Solar PV

Biomass, biogasand urban wastes

Waves and Geothermal

Wind (incl. off-shore)

Total Gross Production of Electricity in 2020:

Natural gas (incl. cogeneration)

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Spanish Renewable Energy Plan 2011-2020

Estimation of daily market price

Cost electricity generation

PV RoofPV Ground

Wind off-shoreWind

CSPWind with 2,900 h/year

Year plant start-up

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For large, state-of-the-art trough plants, current investment costs are USD 4.2/W to USD 8.4/W

CSP: Cost(2 GW learning curve)

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CSP markets: starting in 2007 & only 2GW installed

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The Challenge: Cost reduction

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Parabolic troughs or central tower, operating with thermal fluids at relatively modest temperatures, below 400 ºC .

The most immediate consequences of these conservative designs are: the use of systems with efficiencies below 20%

nominal in the conversion of direct solar radiation to electricity,

the tight limitation in the use of efficient energy storage systems,

the high water consumption and land extension due to the inefficiency of the integration with the power block,

the lack of rational schemes for their integration in distributed generation architectures and

the limitation to reach the temperatures needed for the generation processes following thermochemical routes of solar fuels like hydrogen.

Limitations of first-generation CSP

Extresol 1 and 2 (ACS/Cobra)

PS10 and PS20 (Abengoa Solar)

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295 ºC Oil

395 ºC Oil

Steamgenerator

. Deaerator

ReheaterOil expansion vessel

Steam turbine

CondenserG

Sol

ar F

ield

Steamgenerator

. Deaerator

ReheaterOil expansion vessel

Steam turbine

Condenser

Preheater

Superheated Steam (104bar/380ºC)

ReheatedReheated Steam 17bar/371ºC

G

Sol

ar F

ield

Molten salts(hot tank)

Molten salts(cold tank)

Molten salts(hot tank)

Molten salts(cold tank)

Challenge 1: Storage

Trough Technology with heat storage

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Generation of electricity in Spain during 2011 with CSP (GWh)

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Production week 25-31 July

Production July 2011

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Heat storage: Essential to become dispatchable

• 2-tank molten salt storage for central receiver plants.

• Thermocline pebble bed.• Sand or mobile solid material for

air and particle receivers• PCM/ fins storage for saturated

water/steam

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Thermal energy storageChallenge: < 20-30 €/kWhth

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DESIGN PARAMETERSTotal Reflective Area 285.200 m2

Number of heliostats 2480

Total Area covered by Heliostat Field 142.31 Ha

Thermal output of the Receiver 120 MWt

Tower height 120 m

Heat Storage Capacity (equivalent toturbine operation) 15 hours

Steam Turbine power 17 MWe

Natural Gas Thermal Power 16 MWt

Projected Operative FiguresDirect solar radiation over Heliostats 2062 kWh/m2

Annual Energy sales 96.400 MWhe

Contribution of Natural Gas 15%

Capacity utilization 65 %

CO2 savings 23.000 – 85.000 t/y

Solar Towers and storage: Gemasolar plant

PotenciaSalida

Energía almacén

media-noche

medio-día

Radiaciónsolar

Radiaciónsolar

media-noche

media-noche

medio-día

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ADVANCED Technological Concepts

Heating air Brayton cycle Solar Fuels and Chemicals

Solid Particles Receivers

Ceramic Receivers

High Pressure and High Temperature

C. Brayton Heat air

Ceramic Receivers

Low Pressure and High Temperature

Heat air

Solarized Stirling engines

with receiver Dish-Striling

CURRENT TECHNOLOGIES

Volumetric air receivers (metallic)

Cycle Brayton Preheating air

Molten Salt

Receivers Cycle Rankine Heat steam

Sodium Receivers

Heating air

Water/Steam Receivers

Cycle Rankine Heat steam

Oil Receivers Heating steam

500

ºC 1000

ºC 1500

ºC

Solar Receiver Outlet Temperature

CURRENT

Challenge 2: Higher efficiencies (high T, new fluids)

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Current R+D activities related to Trough TechnologyNew receiver tube designs

New evacuated receiver tube designs with glass-to-metal welds

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Receivers: More compact, durable and efficient(Efficiency > 85%)

New tubular panel for molten salt receiver (SENER)

0 1000 2000 3000

Cur

rent

Nex

tge

nera

tion

Peak flux on aperture (kW/m2)

VolumetricMolten saltWater-steam

Direct Indirect Particles Tubular Volumetric Fluid - Water Liquid metals Molten Salts Air Average flux (MW/m2) Peak flux (MW/m2)

(0.9) (2.5)

0.1-0.3 0.4-0.6

0.4-0.5 1.4-2.5

0.4-0.5 0.7-0.8

0.5-0.6 0.8-1.0

Fluid outlet temperature (ºC) (2,000) 490-525 540 540-565 (700-1,000)

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gas

inlet

exit

wal

lgas

gas

absorber

tube receiver volumetric receiver

inlet exit

concentrated solar radiation ~ 1000 kW/m

2

concentrated solar radiation ~ 200 kW/m

2

Volumetric receivers: a good example of high T solar absorption

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Volumetric air-cooled receiver

Incident solar flux

ambient air

absorber structur

SiSiC cup

cooling air

orifice

insulation

hot air

Heat transfer area: 255 m2/m3

Efficiency at 750°: 78% Porosity: 50%

Target:• Improve volumetricity• Increase solar flux

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Superheating steam with dual receivers

eSolar Double Cavity

B&W receiver

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Solar receiver: Reliable black-body is the key

Operational range for different solar receivers (Source: A. Kribus)

0

500

1000

1500

2000

0 20 40 60 80 100 120 140 160

Pressure (bar)

Tem

pera

ture

(ºC

)

Volu-metric

Futuredevelopments

Tubular cavity

Tubular external

Trough linear

n Water-steam need to develop super-heating at high solar flux.

n Volumetric should improve volumetric effect without penalizing fluid-dynamics and flux profile flexibility.

n Molten salt should demonstrate long-term availability and increase peak flux

n Particle receivers and falling films still to pass feasibility phase.

n All should accumulate operational experience and long-term endurance tests.

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El heliostato de SenerChallenge 3: Cheaper concentrators

Large areaheliostats

New reflectors

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The Solar Energy Development CenterSmall heliostats

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Key data on the solar power station PE 2

Manufacturer Novatec SolarProduct name Nova-1

Model28 rows of linear Fresnel collectors,conventional steam turbine equipment and generator

Solar field length 1.000 m

Net aperture area 302,000 m²

Operating temperature Up to 270 °C

Operating pressure Up to 55 bar

Peak thermal output 150 MWth

Peak electrical output 30 MWel

Planned current output 49 GWh/year

Linear Fresnel

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multitowers

Multitower arrays

Challenge 4:Modularity

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Modularity, urban integration

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Challenge 5: Uncertainty DNI

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Methodology

Based upon images of visible channel from geostationary satellites

Genertion of large temporary series

Estimation of DNI from satelliteimages

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MW-Scale High Fux/High Temperature Solar is possible

Central Receiver

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Challenge 6: Solar ChemistryHigh Flux/High T Solar Reactors

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• 1774: Oxygen is discovered by Joseph Priestly (30 cm diameter lens).

• Antoine Lavoisier formulated the theory of combustion.

• Lavoisier built a solar furnace (>1 m diameter), achieving more than 1700ºC and melted Pt.

Solar Furnace of Antoine Lavoisier(Ilustration XVIII century)

Solar Concentration technologies: Solar Chemistry was first!!!!!

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CONCLUSIONS

CSP introduces solar energy to high-value markets on high temperature processes, providing high capacity and dispatchability.

Solar thermal power plants offer a wide portfolio of integration options with heat storage or hybrid operation for massive production of electricity.

First commercial projects already going on in Spain, USA and elsewhere.

Substantial R&D still needed to reduce costs by 60% Solar Fuels & Chemicals the ultimate target.

CSP: