Solar power status and perspectives – DESERTEC an … unit plant size of up to ~250 MW is possible...

© Siemens AG 2010Energy Sector

Siemens Press Trip Seville, Lebrija April 13, 2010

Dr. Bernd Utz Head of the Project Desertec Initiative of the Renewable Energy Division

Solar power status and perspectives – DESERTEC an update

Energy SectorApril 13, 2010 Dr. Bernd Utz © Siemens AG 2010Slide 1

Solar irradiation: PV versus CSP

The total irradiation reaching ground is the global irradiation. It consists basically of two irradiation types:

Direct normal irradiation (DNI) is using sun beams that still come directly from the sun‘s direction and are almost parallel

Diffuse irradiation was redirected as it passed for example humidity or dust or was reflected by clouds or water/ice surfaces

CSP can only use DNI whereas PV is using a mix of direct and diffuse irradiation called global horizontal irradiation (GHI).

Example: South East Asia has a high amount general irradiation but only little direct irradiation as a result of the monsoon weather regimes.

Global irradiation works for PV useDirect irradiation works for CSP use


Solar applications: Typical allocation of solar applications to different regions

Temperature irradiation Land consumption Dispatch ability

Crystalline silicon Low Diffuse to direct Moderate No

Thin film Medium to high Diffuse to direct Large No

Concentrating PV High Direct only Little No

Solar thermal (CSP) High Direct only Moderate Yes, with some storage

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DESERTEC project pushes development of solar activities in EU-MENA

region


CSP technologies: Four different CSP technologies are on the market for large-scale applications

The parabolic trough is currently the most commercially viable solution

Parabolic Trough

Stirling Dish EngineLinear Fresnel

Central Tower

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Presenter

Presentation Notes

Four CSP technologies existing 1) Parabolic Trough 2) Central Tower 3) Linear Fresnel 4) Stirling Dish Engine All technologies concentrating solar irradiation by mirrors -> direct sunlight, no diffuse light utilization Dish engine: Stirling engine driven by heat Direct power generation in solar field Development in test stage Size: 25 KW Central Tower: Flat mirrorfield focuses sun on central point receiver at top of tower High temperatures up to 565 °C 2 axis sun tracking Demostage (PS10 11MW installed) Size 50 MW Storage feasible Linear Fresnel: Flat, low cost mirror focusing sunlight on receiver tube 1 axis suntracking Lower temperatures Size: 50 MW Parabolic Trough: U-Shape mirrors focus sunlight on receiver tubes 1 axis tracking Higher temperature 400-550 °C Storage feasible > 400 MW installed


Concentration of sun rays on the focus line of parabolic trough(absorber tube)Two-cycle system (state-of-the-art: Oil / water)Main steam parameters: 380°C / 100 bar (HTF=thermo oil)Annual average efficiency (net): 12–15% (demonstrated)

Most proven and bankable technology(~350 MW with more than 15 years experience)Single unit plant size of up to ~250 MW is possibleEasy integration of thermal storage system dispatchwhen energy is neededCombination with process steam and ISCC possibleGood modularity of collectors

Strengths

Limitation of oil temperature to <400°CWater consumption in cooling towersAlternative: ACC with reduced overall efficiency

Weaknesses

CSP technologies: Parabolic trough technology is the only long-term proven technology

Technology


Siemens Solar Field: The SunField LP

A complete, reliable, warranted and bankable solar field, based on Siemens' vast CSP experience

Lebrija Site Spain, Feb. 2010

The only supplier that develops, manufactures and installs all the critical components of the solar field, including receivers, mirrors and collectorsSiemens's unique vertically integrated offering

enables a guaranteed performanceOperational know-how and efficiencyAdvanced command and control system which

maximizes performance and revenues


Optical Efficiency by automation and industrialization of constructionQuality in all dimensionsTransferable construction and training methodology Onsite engineering support

Siemens Solar Field: Construction

Quality and Precision


The SOLEL 6 Collector: The road to an improved trough design

Siemens designed a new collector – Solel 6, based on past experiences from LuzSolel 6 collector azimuth tracking platform enables testing all incident angles

An entire loop in the Negev test siteSolel 6 and its components tested for over three yearsOn site construction and production methodology optimized

Alpha Site

Beta Site


Absorption (α) >96%Emissivity (ε) typically below 9% at 400°CActive area to length ratio -96.3% Low profile radiation shieldPatented getters device – keeps vacuum levelCoating durable in air, resistant to fluorescents phenomena

UVAC has a track record of decades of field proven reliabilityOver 220,000 units already delivered and booked orders of around 130,000 units

Solar receiver: The UVAC 2010 Oil Receiver

Proven technology

Technical Data

Key FeaturesNew performance benchmarkMost efficient receiver in the market


Consisting of outer glass and inner metal tubeVacuum in between, reducing convection lossesHeat transfer fluid: molten salts

Special spectrally-selective coating (CERMET) ensures maximum sunlight yield Capable of highest temperaturesOperation with molten salt

Proven Basic Concept

Technical Data1)

Key Features

1) Parabolic Trough w/ molten Salt

Absorptance α [%]: ~ 95Emissivity ε [%]: ~ 10 @ 400°C

~ 14 @ 580°COperating temperature [°C]: ~ 300-550Tube length [m]: ~ 4Tube diameter [cm]: ~ 12

Solar receiver: The Archimede Molten Salt Receiver HEOI09

Siemens is a shareholder in Archimede Solar Energy

Presenter

Presentation Notes

Glass tubes: Main technological aspects Tubing glass manufacturers: Schott Rohrglas Few other sources Special glass composition High IR transmission (low Fe content) Thermal expansion matched to steel Large dimensions: > 4 m length, 10 cm diameter Absorbers: Main technological aspects Doped or multi-layer systems Long-term stability at > 400°C, thermal cycling Layer concept for absorbers differs from radiation layers (lighting, x-rays): Maximize temperature�(instead of minimizing) Low IR emissivity (instead of high ε) Absorption/emission balance defines the achievable temperature (@ ideal isolation):


CSP technologies: HTF type molten salt

BasicsLiquid molten salt widely used as heat transfer medium in process industry (e.g. melamine, alumina production) Molten Salt stable up to 550°C, melting point 220°CGoal for main steam temperature: > 500°CHeat transfer to conventional Rankine Cycle via heatexchangers

Low pressure design for solar cycleHigh annual average efficiency (projected >18%)Easy integration of thermal storage systemHeat transfer in liquid phase onlyEnvironmentally friendly

Strength

Freezing of molten salt >> 150°C (heating necessary) Corrosion behavior (special materials required)Two cycle system

Weakness


BasicsSynthetic oil, mixture of di phenyl and bi phenyl oxide Maximum reachable steam temperature: < 385°CHeat transfer to conventional Rankine Cycle via heat exchangersAnnual average efficiency ~ 15%

More than 15 years operating experience in solar power plantsHeat transfer in liquid phase only

Strength

Upper temperature limit of 400°C, overheating to be avoidedFlammable and toxicHeating necessary below 50°CThree cycle system in case of thermal storage system

Weakness

CSP technologies: HTF type thermal oil


CSP technologies: HTF type direct steam

BasicsDemineralized water as working fluidDirect heat transfer to conventional Rankine CyclePotential for main steam temperature: > 500-600°C 1, 2)

One cycle system resulting in lower invest and operating costsLess components and systems neededHigh annual average efficiency possible 1, 2)

Cheap and availableEnvironmentally friendly

Strength

Heat transfer in liquid and gaseous phaseThermal storage not available for large scale applicationsHigh nominal pressure in solar field 1)

Complex controlling effort in case of insulation fluctuationsDemonstration up to 500°C steam temperature 1)

Demonstration of single loops only 1)

Weakness

1) Parabolic trough; 2) Solar tower; 3) saturated steam only


HP module

LP moduleGear box Generator

As of September 2008, Siemens has booked orders for 45 steam turbines for solar thermal power plants

40 steam turbines for CSP trough technology3 steam turbines for solar tower2 steam turbines for ISCC power plants

Power Generation: Steam turbine for solar thermal application

Siemens solar steam turbines references

Power train SST-700 DRH with SGen5-100A-2P series generator


Dual-casing reheat turbine (DRH)HP module geared to LP module / generatorMiddle position of generator

Power output [MW]: 50Inlet pressure [bar]: 100Inlet temperature [°C]: 377Reheat temperature [°C]: 380Rotational speed [rpm]: 9,000 / 3,000

Condensing typeCustomized steam path for high efficiencyLow mass rotor and casings for highest cycling capabilitiesAxial exhaust

Market-leading steam turbine for solar applications SST-700 DRH

Features

Technical data 1)

General


Best practice in projects Lebrija/Spain CSP power plant

■ Pioneer CSP plant in Spain■ Capacity of 50 MW■ Parabolic trough technology■ Thermal oil as heat transfer fluid■ Built by Solel and Valoriza

Project profile


A vision for clean energy becomes reality – DESERTEC

Provide up to 100 GW of renewable capacity by 2050

Excellent potential for wind and solar power

Power used in North Africa as well as Europe

Low-loss electricity transport via HVDC from North Africa to Europe

The DESERTEC concept

Presenter

Presentation Notes


Siemens HVDC* transmission technologies for the Desertec concept

DC sea cable connections (400 kV, ca 600 MW, ca 300 km)

DC long distance transmission (±800 kV, 5000 MW, 1400 km)

Project Bass Link Project Yunnan

* HVDC: High voltage direct current


Hydro Power with 800kV HVDC Transmission

The hydro power of Yunnan can only transmitted with HVDC to the Hong Kong region.

HVDC with the largest transmission capacity of 5000 MW over a distance of 1400 km.

First 800kV HVDC line worldwide.

CO2 abatement of 30 Mio. tonnes per year


Wind> 20...40 GW

Hydro> 10..30 GW

2000 km

1800 km

Load CentresSolar > 10..20 GW

2000 km

Hydro> 30...50 GW

Integration of Renewable Energies is feasible - HVDC plays a central role

Use of hydro power in China Use of renewable energy in Europe


Onshore wind power

Energy Sector plays a key role in the DII GmbH

The DESERTEC concept – A great opportunity for the joint Energy Team

Offshore wind parks – Photovoltaics HVDC power transmission lines

Solar field Receiver Power block Steam turbinesConcentrated solar power plant

Solar power status and perspectives – DESERTEC an … unit plant size of up to ~250 MW is possible...

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