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Concentrating Solar Power (CSP)From Solar Fundamentals to CSP Plant Modeling
Dr. Rafael Guédez September 5, 2018
KTH Industrial Engineering and Management
Researcher – Energy Department MASEN Talent Campus, Agadir, [email protected]
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 2
Agenda© SolarReserve
9:00 – 9:45 Introduction• Solar Fundamentals
• CSP Technology Basis
10:00 – 10:45 CSP Technology, Market & Prospects• Overview of technologies (cont.): projects
• Market outlook, Drivers and Prices
11:15 – 12:30 Thermal Energy Storage (TES)• On the value of TES in CSP
• Review of TES technologies for CSP
2:00 – 3:30 Modeling of CSP Plants with TES• Review on Project Development and Actors
• Power Plant Techno-economic Modeling approach
3:40 – 5:00 Case study: Simulation in SAM
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 3
Agenda© SolarReserve
9:00 – 9:45 Introduction• Solar Fundamentals
• CSP Technology Basis
10:00 – 10:45 CSP Technology, Market & Prospects• Overview of technologies (cont.): projects
• Market outlook, Drivers and Prices
11:15 – 12:30 Thermal Energy Storage (TES)• On the value of TES in CSP
• Review of TES technologies for CSP
2:00 – 3:30 Modeling of CSP Plants with TES• Review on Project Development and Actors
• Power Plant Techno-economic Modeling approach
3:40 – 5:00 Case study: Simulation in SAM
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 4
Introduction: about meAt Academia: • Research Leader in Solar Power (CSP and PV) and thermal power cycles at KTH• Research Leader in Power Plant Techno-economic Modeling at KTH• Lecturer, course responsible and supervisor at MSc and PHD level at KTH.
At Industry:• Director at Europe Power Solutions (Consulting)• Advisor in Strategy and Technology to Azelio AB• Senior Performance Analyst at SolarReserve LLC
Education / Background:• PhD in CSP Plant Techno-Economic Performance Modeling – KTH • Executive programs in Business Administration, Marketing and Negotiation (ESADE, GEM, MIT)• Mechanical Engineering – Universidad Simon Bolivar (Venezuela)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 5
Introduction: KTH• Sweden’s oldest
Technical University
• Founded in 1827
• +12000 students
• 10 Schools
• World Rankings:• 36 (Times - Engineering 2017)• 25 (QS Top Universities – Energy Engineering 2016)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 6
Introduction: KTH• Sweden’s oldest
Technical University
• Founded in 1827
• +12000 students
• 10 Schools
• World Rankings:• 36 (Times - Engineering 2017)• 25 (QS Top Universities – Energy Engineering 2016)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 7
Introduction: KTH CSP R&D Group
• + PostDoc, 3 PhD students+ 20 MSc Students and affiliates
• In close collaboration with industryand other R&D institutes
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 8
Solar EnergyIEA Energy Outlook: + 6°C by 2050
Solar Energy is the mostabundant renewable resource on Earth
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 9
Solar Basics: Radiant Flux1. The Sun’s energy radiates outwards into space from the photosphere..2. The intensity of the radiation decreases in accordance with the inverse-square law.3. At Earth’s mean orbital then it is internationally accepted the value of 1367 [W/m2]4. At atmosphere limits, incident radiation approaches a black-body distribution.
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 10
Solar Basics: Radiant Flux
Indeed, the Earth is closest to the Sun in January (perihelion) and furthest away in July (aphelion)
Incident flux on Earth varies due to its elliptical trajectory around the Sun
−
+⋅=365
22cos034.01 nII sco π
For a given day
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 11
Solar Basics: Atmospheric EffectsDuring passage through Earth’s atmosphere, partial flux is scattered or absorbed
Even on a clear day, up to 30% of the incoming radiation is absorbed
The peak flux at the Earth’s surface is approx. 1kW/m2
Largest losses result from absorption and reflection
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 12
Solar Basics: Atmospheric EffectsThe amount of scattering and absorbing is expressed by means of the air mass,the ratio of the actual path length to the path length when the Sun is directly overhead
( ) 636.1cos08.965057.0cos1
−−+=
zz
AMθθ
Standard design assumption:AM = 1.5 (850 W/m2)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 13
Solar Basics: Radiation Components
Beneath Earth’s atmosphere, Solar flux is divided into two components: Beam and Diffuse radiation, which sum is known as the Global Irradiation
diffusebeamglobal III +=
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 14
Solar Basics: Radiation Components
The incident solar radiation at a site can be measured using a pyranometer, which measures the global solar irradiation.
Placed flat, thus measuring thehorizontal global irradiance:
diffusezbeamhglobal III +⋅= )cos(, θ
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 15
Solar Basics: Solar Time
1. Solar time: defines 12:00 as the moment when the Sun is exactly due South at the local position of the observer.
2. Clock time: defines 12:00 as the moment when the Sun is due South for an observer on the local standard time zone meridian
Two key concepts:
DSTEOTlocstd
clks tttt ∆+∆
+°−
+=6015
ψψts: solar time [hrs]tclk: clock time [hrs]Ψstd: time zone meridian [°W]Ψloc: local longitude [°W]ΔtEOT: equation of time [min]ΔtDST: daylight saving time [hrs]
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 16
Solar Basics: Earth-Sun GeometryThe direction of the incident beam radiation depends on the position of the Sun, which varies throughout the day. Moreover, the Sun’s path for a location depends on its latitude and the day of the year (through the declination angle)
−
=365
1732cos39795.0arcsin nπδDeclination angle:
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 17
Solar Basics: Earth-Sun GeometryThe design of solar energy systems requires knowledge of the position of the Sun throughout the day, which can be defined using a number of angles:
First step: convert local solar time into the Hour Angle.The angle through which the Earth has rotated since noon
Hour Angle ( )1212
−= stπω
Noon: ω = 0Midnight: ω = ±180
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 18
Solar Basics: Earth-Sun GeometryThe design of solar energy systems requires knowledge of the position of the Sun throughout the day, which can be defined using a number of angles:
( )δϕωδϕθ sinsincoscoscosarccos +=z
−=
ϕθδϕθ
ωγcossin
sinsincosarccos)sgn(z
zs
zs θθ −= 90
Zenith Angle
Azimuth Angle
Elevation Angle
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 19
Solar Basics: Radiation on a SurfaceThe intensity of radiation that is incident on a given surface is dependenton the relative orientation of the surface and the position of the Sun.The position of the surface (or aperture) can be defined by two angles:
The slope angle βc defined between the normal to the aperture and the zenith
The surface azimuth γc defined by the surface normal clockwise from due-South
( )( )cszczc γγθβθβθ −+= cossinsincoscosarccos
For determining radiant flux on a given surface, the Incidence Angle is needed:
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 20
Solar Basics: Radiation on a SurfaceWhen the incident radiation does not arrive normal to a collector, the surface intensity (Ic) of the radiation is reduced. This is known as cosine effect
θcosocccob AIAIAI ==
Cosine Effectiveness:
θε coscos ==b
c
II
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 21
Solar Basics: TrackingSingle-axis tracking system can be defined by certain quantities:
Tracking Angle (ρ): fixed by the tracking system and adjusted throughout the daySolar Tracking Incidence Angle (θt)Tracking Axis (n): vector about which the tracking system rotates to position the collector
DUAL-AXIS TRACKING
εcos = 100%
SINGLE-AXISTRACKING
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 22
Electricity from Solar Energy
Solar energy is harnessed mainly by two key technologies to produced electricity. Both of them commercial and in continuous development
Concentrating Solar Power (CSP) Solar Photovoltaic (PV)
© SENER
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 23
CSP Technology Basics
SOLAR ENERGY HIGH TEMPERATURE HEAT ELECTRICITY
THERMAL ENERGY STORAGE (TES)
HYBRIDIZATION
© Torresol Energy © Torresol Energy
TES
Solar Field(Heliostats)
ReceiverTower
Power Block
3 Main Blocks: Solar Field, TES, Power Block
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 24
CSP Technology Basics
SOLAR ENERGY HIGH TEMPERATURE HEAT ELECTRICITY
THERMAL ENERGY STORAGE (TES)
HYBRIDIZATION
© DLR
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 25
CSP Technology Basics
Fresnel Tower Dish Trough
Maturity Early commercial projects going online
Proven(First large projects)
DemonstrationProjects
Proven(most mature)
Tracking No tracking 2 axes tracking 2 axes tracking 1 axis tracking
Receiver Linear – Fixed Point - Fixed Point - Movable Linear - Movable
Storage Available, not proven Commercially Available Probable – not yet available
Commercially Available
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 26
CSP Basics: Concentration RatioConcentration increases density of the radiant energy flux, allowing more power to be absorbed for agiven surface area and thus a more effective receiver operation at higher temperatures
The CR varies depending on the technology and is an indicator of the system efficiency.The CR is connected to reachable temperatures and thus to identifying suitable power cycles.
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 27
Agenda© SolarReserve
9:00 – 9:45 Introduction• Solar Fundamentals
• CSP Technology Basis
10:00 – 10:45 CSP Technology, Market & Prospects• Overview of technologies (cont.) & projects
• Market outlook, Drivers and Prices
11:15 – 12:30 Thermal Energy Storage (TES)• On the value of TES in CSP
• Review of TES technologies for CSP
2:00 – 3:30 Modeling of CSP Plants with TES• Review on Project Development and Actors
• Power Plant Techno-economic Modeling approach
3:40 – 5:00 Case study: Simulation in SAM
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 29
Parabolic Trough PlantsSolana 280 MWeArizona, USA – 2013Abengoa
Solar Field: Therminol VP1Storage: 6h 2 Tanks indirect (molten salts)
Power Block: Rankine Reheat
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 30
Parabolic Trough Plants
Andasol: 3 x 50 MWeGranada, Spain– 2008ACS Cobra - SENER
Solar Field: Therminol VP1Storage: 7h 2 Tank indirect (molten salts)
Power Block: Rankine Reheat
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 31
Parabolic Trough PlantsAmal West Field: 8 MWthAmal, Oman – 2014GlassPoint Solar – PDO, Shell, Total
Solar Field: Enclosed Parabolic Troughs for DSG
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 32
Parabolic TroughsSolar Collector Assembly (SCA)
Absorber Tube / Heat Collection Element (HCE)
Support Structure
Drive Pillar
Flexible Joint
Intermediate Pillar
Parabolic Mirror / Trough Collector
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 33
Parabolic Troughs
The net energy supplied by a given SCA is a function of a number of factors, and can be defined by:
( )( )endshdsurfoSCASCA ffIAQ −−⋅⋅⋅=+ 11IAMcosεε
QSCA: thermal power [W] εcos: cosine effectiveness [-]ASCA: SCA aperture area [m2] fshd: shadowing factor [-]Io: incident beam radiation [W/m2] IAM: incidence angle modifier [-]εsurf: surface effectiveness [-] fend: end-loss factor [-]
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 34
Parabolic Trough Plants: Schematics
STORAGE SYSTEM
SOLAR FIELD - HTF CYCLE POWER CYCLE
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 36
Solar Towers
Gemasolar: 20 MWeSeville, Spain – 2011Torresol (SENER)
Solar Field: Molten Salt towerStorage: 2 Tank Direct, 15h
Power Block: Rankine Reheat
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 37
Solar Towers
Ivanpah SEGS: 3 x 120 MWeCalifornia, USA – 2013Brigthsource
Solar Field: DSGStorage: no TESPower Block: Rankine Reheat with ACC
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 38
Solar Towers
Crescent Dunes: 110 MWeNevada, USA – 2015Solar Reserve
Solar Field: Molten Salt towerStorage: 2 Tank Direct, 10h
Rankine Reheat
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 39
Solar Towers
© B
rightsource
© Chevron Coalinga Oil Field: 30 MWthCalifornia, USA – 2013Brigthsource
Solar Field: DSGStorage: No TESPower Block: Process heat for EOR
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 42
Solar TowersCentral Receiver
Heliostats
Tower
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 43
Solar TowersHeliostats: Sun-tracking mirrors mounted on dual-axis tracking structures
Designing addresses different aspects:
High reflectivityHigh optical precisionHigh tracking accuracyResistant structure
The aim is then to simultaneously address:• Collector efficiency• Temperature
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 44
Solar Towers: Heliostats
( )( )( )( )spillattblockshadsurfohh ffffIAQ −−−−⋅⋅=+ 1111cosεε
Qh: thermal power [W] εcos: cosine effectiveness [-]
Ah: heliostat surface area [m2] fshad: shadowing factor [-]
ρh: mirror reflectivity [-] fblock: blocking factor [-]
Io: incident beam radiation [W/m2] fatt: attenuation factor [-]
εsurf: surface effectiveness [-] fspill: spillage factor [-]
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 47
Solar Tower Plants: SchematicsHTF CYCLE POWER CYCLE
STORAGE SYSTEMSOLARFIELD
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 48
CSP Market Today
6 GWe Installed Capacity
75%Parabolic Trough
25%Tower
Spain 2.4 GW - USA 1.9 GW
2GWeTendered - Under
Construction
50%Parabolic Trough Tower
China 1 GW - Morocco 0.7 GW
50%
70% w/ STORAGE 100% w/ STORAGE
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 49
CSP: Troughs vs Towers
• Maturity:
• Standardization of component development. More players.
• Proven, easier for bankability (finance).
• Achieved significant cost reduction due to technology improvements.
• O&M best practices known (e.g. Spain is increasing generation share).
• Solar field size is not limited as in towers larger power blocks.
• More ‘Modularity’ than for towers (specially for industrial process heat)
Parabolic Troughs:Despite being less efficient more projects will be built. Why?
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 50
CSP: Troughs vs TowersSolar Towers:The share of ST is only increasing. Why?• Higher CR, higher temperatures and system efficiency:
• Double axis tracking.
• Allowing for superheated steam and also gas turbine power blocks.
• More secure: HTF is ‘safe’ (non-flammable) & restricted to ‘smaller’ areas.
• Molten Salts are easier to control and to store directly (no additional HEx).
• Although being a less mature tech, there is room for innovation, thus a great potential for driving down costs
• Bankability: Technology proven to be reliable (Gemasolar)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 51
Upcoming Solar Tower Plants
• 2020: 110 MW Redstone, South Africa (10h TES – molten salts)
• 2019: 110 MW Cerro Dominador, Chile (17.5h TES – molten salts)
• 2018: 150 MW Noor III, Morocco (7.5h TES – molten salts)
• 2018: 121 MW Ashalim, Israel (DSG – no TES)
• 2018: 50 MW Khi Solar One, South Africa (DSG – 2h TES)
• 2020: 2x100 MW DEWA, Dubai (10h TES – molten salts)
• 2021: 150 MW Aurora Project, Australia (7.5h TES –molten salts)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 52
CSP Deployment Drivers• Technical: Renewable and dispatchable (cost-efficient and reliable storage)• Macroeconomic: Local content of CSP plants is one of largest for renewable projects• Technical Developments – Higher efficiencies• Cost Developments:
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 53
CSP 2030 Market Outlook and Scenarios
9h STORAGE
* For a 200$/kWh combined battery and batteryBOS costs and increased lifetime
* For PV systems (module + BOS) of 1$/W
27GWe
130GWe
SOLARPACES - ESTELA
87GWe
155GWe
IRENA IEA 2D
Current policy Moderate policy
(2016)
(2015)(2014)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 54
CSP Market Outlook: Prices
63$/MWh
Chile 2016DNI: 3400
73$/MWh
UAE 2017DNI: 2200
• CSP is generally seen as less competitive on the basis of $/MWh
• We are seeing aggresive PPA bids,yet higher than other renewables e.g. PV
• It is now being understood that its value relies on its dispatchable attribute.
This has led to tech-specific tenders with time-of-use tariffs (hourly)
This means that the optimum design and operation of each plant is unique to each tender and location
220 MW Tower14h TES
200MW Tower8-10h TES
© SolarPACES-ESTELA 2016
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 55
Agenda© SolarReserve
9:00 – 9:45 Introduction• Solar Fundamentals
• CSP Technology Basis
10:00 – 10:45 CSP Technology, Market & Prospects• Overview of technologies (cont.): projects
• Market outlook, Drivers and Prices
11:15 – 12:30 Thermal Energy Storage (TES)• On the value of TES in CSP
• Review of TES technologies for CSP
2:00 – 3:30 Modeling of CSP Plants with TES• Review on Project Development and Actors
• Power Plant Techno-economic Modeling approach
3:40 – 5:00 Case study: Simulation in SAM
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 56
CSP Deployment Drivers• Technical: Renewable and dispatchable (cost-efficient and reliable storage)• Macroeconomic: Local content of CSP plants is one of largest for renewable projects• Technical Developments – Higher efficiencies• Cost Developments:
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 57
Thermal Energy Storage (TES) IntegrationPower plants have different roles in the electricity market
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 58
Thermal Energy Storage (TES) IntegrationWhen designing a system, not only the nominal power and demand
should be considered, but also how is the system expected to operate
Power plants have different roles in the electricity market
This is often decided by the System Operator and Utilities
The role and share of a technology in the market is policy-related
CSP Plants with storage are dispatchable and thus able to fulfillany specific role, for which then the system can be designed for
Decision making involves multiple stakeholders and is based on policy, incentives, regulations and demand that define the market
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 59
Thermal Energy Storage (TES) Integration
CSP Plants withstorage are
dispatchable and flexible
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 60
Thermal Energy Storage (TES) IntegrationDepending on the role of the CSP plant, and specifically of
the TES system, the solar field might be oversized
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 61
Thermal Energy Storage (TES) IntegrationDepending on the role of the CSP plant, and specifically of
the TES system, the solar field might be oversized
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 62
Thermal Energy Storage (TES) Integration
The size of our TES system will be defined based on market needs or desired plant operating strategy
…we measure it through the storage capacity in hours,related to the thermal capacity through the following equation:
][ thhCAPPBthCAP MWhTESQTES −− ⋅=
…where QPB is the thermal power required from the PB at nominal design
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 63
Thermal Energy Storage (TES) Integration
The size of the SF then needs to be related to the desired operation and TES size:
)/(SM
min recnomPB
nomSF
SF
nomSF
η
==
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 64
Thermal Energy Storage (TES) IntegrationDesign considerations:It is desired for the plant to be able to operate under nominal conditions when running from TES, so systems are dimensioned based on discharging
• NaNO3-KNO3• Freezing point 270 °C• Stable up to 580 °C.
TES media: Solar Salt
2 Tanks in Parabolic Trough Plants
≈ 290 °C
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 65
Thermal Energy Storage (TES) Integration
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 66
Thermal Energy Storage (TES) Integration
Tanks
Salt Pumps
HTF-Salt Heatexchangers
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 67
Thermal Energy Storage (TES) IntegrationDesign considerations:Different high temperature TES concepts and technologies exist:
Active TES Passive TESForced convection heat transfer
into TES mediumTES medium passes through
heat exchanger *Direct: HTF = TES medium
E.g.: 2-Tank Direct (Gemasolar)Indirect: HTF ≠ TES mediumE.g.: 2-Tank Indirect (Andasol)
Dual medium TES systemsHTF charges/discharges
a solid materialAlso called regenerators
E.g.: Concrete TESPCM TES
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 69
TES: Sensible Heat
In sensible heat storage systems, variations of the stored energy are dependent on the variation of the mean temperature
∆𝑄𝑄𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 = 𝑚𝑚 �ℎ(𝑇𝑇1)
ℎ(𝑇𝑇2)
𝑑𝑑𝑑 = 𝑚𝑚 �𝑇𝑇1
𝑇𝑇2
𝑐𝑐𝑝𝑝 𝑇𝑇 𝑑𝑑𝑇𝑇
∆𝑄𝑄𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 ≈ 𝑚𝑚 � �̅𝑐𝑐𝑝𝑝 𝑇𝑇1
𝑇𝑇2� 𝑇𝑇2 − 𝑇𝑇1
𝑞𝑞 = 𝑑 = 𝑇𝑇𝑑𝑑𝑇𝑇
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 70
TES: Sensible Heat Example: Concrete
Concrete TES
Start
Discharging
Charging
End
Charged
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 71
TES: Sensible Heat Example: Concrete
Start
Discharging
Charging
End
Charged
𝑄𝑄1 = 𝑚𝑚 � 𝑑(𝑇𝑇1)
𝑄𝑄3 = 𝑚𝑚 � 𝑑(𝑇𝑇3)
𝑄𝑄2 = 𝑚𝑚 � 𝑑(𝑇𝑇2)
∆𝑄𝑄𝑠𝑠𝑠𝑠𝑠𝑠 = 𝑚𝑚 � 𝑑 𝑇𝑇2 − 𝑑(𝑇𝑇1)
∆𝑄𝑄𝑠𝑠𝑠𝑠𝑟𝑟 = 𝑚𝑚 � 𝑑 𝑇𝑇2 − 𝑑(𝑇𝑇3)
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 72
TES: Sensible Heat Example: Concrete
Start
Discharging
Charging
End
Charged
Simplification
In order to simplify the calculation the heat exchanger charging/discharging efficiency εis introduced
𝑄𝑄𝑠𝑠𝑠𝑠𝑟𝑟𝑠𝑠𝑠𝑠 = 𝑄𝑄𝑓𝑓𝑟𝑟𝑓𝑓𝑠𝑠𝑠𝑠 � 𝜀𝜀𝑐𝑐ℎ
𝑄𝑄𝑓𝑓𝑟𝑟𝑓𝑓𝑠𝑠𝑠𝑠 = 𝑄𝑄𝑠𝑠𝑠𝑠𝑟𝑟𝑠𝑠𝑠𝑠 � 𝜀𝜀𝑠𝑠𝑠𝑠𝑠𝑠
Charging:
Discharging:
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 75
Agenda© SolarReserve
9:00 – 9:45 Introduction• Solar Fundamentals
• CSP Technology Basis
10:00 – 10:45 CSP Technology, Market & Prospects• Overview of technologies (cont.): projects
• Market outlook, Drivers and Prices
11:15 – 12:30 Thermal Energy Storage (TES)• On the value of TES in CSP
• Review of TES technologies for CSP
2:00 – 3:30 Modeling of CSP Plants with TES• Review on Project Development and Actors
• Power Plant Techno-economic Modeling approach
3:40 – 5:00 Case study: Simulation in SAM
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 76
CSP Project Development: Bid TendersThere are multiple stakeholders involved in the value-chain
of the development of a CSP plant under a competitive bid tender
Each one with different interest so PPA price is not the only design objective
This makes the optimum design and operation more challengingand also dependent on the actual stakeholder
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 80
CSP Techno-economic Modeling
a number of design objectives shall be considered in the evaluation of CSP plants
and also dependent on the stakeholder
These are all relevant decision criteria and often conflicting
Optimization Trade-offs
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 81
CSP Performance Indicators
TECHNICAL ENVIRONMENTAL
Annual Yield (Enet ) [GWh]
Capacity Factor (CF) [%]
𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑌𝑌𝑌𝑌𝑌𝑌𝐴𝐴𝑑𝑑8760 × 𝑁𝑁𝑁𝑁𝑚𝑚𝑌𝑌𝐴𝐴𝐴𝐴𝐴𝐴 𝐶𝐶𝐴𝐴𝐶𝐶𝐴𝐴𝑐𝑐𝑌𝑌𝐶𝐶𝐶𝐶
Annual Specific CO2 Emissions [kg CO2/MWh]
FINANCIAL (Costs)
Investment Costs (CAPEX) [$] Annual Operational Costs (OPEX) [$/y]
𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐶𝐶𝐶𝐶2 𝐸𝐸𝑚𝑚𝑌𝑌𝑇𝑇𝑇𝑇𝑌𝑌𝑁𝑁𝐴𝐴𝑇𝑇𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑌𝑌𝑌𝑌𝑌𝑌𝐴𝐴𝑑𝑑
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 82
CSP Performance Indicators
FINANCIAL (Performance)
Levelized Cost of Electricity [$/MWh] Internal Rate of Return (IRR) [%]
𝐷𝐷𝑌𝑌𝑇𝑇𝑐𝑐.𝐶𝐶𝐴𝐴𝑇𝑇𝑑 𝐶𝐶𝐴𝐴𝐶𝐶𝑂𝑂𝐴𝐴𝑁𝑁𝑂𝑂𝑇𝑇𝐷𝐷𝑌𝑌𝑇𝑇𝑐𝑐.𝐸𝐸𝐴𝐴𝑌𝑌𝑐𝑐𝐶𝐶𝐸𝐸𝑌𝑌𝑐𝑐𝑌𝑌𝐶𝐶𝐶𝐶 𝐺𝐺𝑌𝑌𝐴𝐴𝑌𝑌𝐸𝐸𝐴𝐴𝐶𝐶𝑌𝑌𝑁𝑁𝐴𝐴
𝐿𝐿𝐶𝐶𝐶𝐶𝐸𝐸 = 𝑂𝑂 𝐶𝐶𝐴𝐴𝐶𝐶𝐸𝐸𝐶𝐶,𝐶𝐶𝐶𝐶𝐸𝐸𝐶𝐶,𝑌𝑌𝑌𝑌𝑌𝑌𝐴𝐴𝑑𝑑,𝐷𝐷𝐷𝐷
𝐷𝐷𝐷𝐷 = 𝑊𝑊𝐴𝐴𝐶𝐶𝐶𝐶 = 𝑂𝑂𝐸𝐸𝑞𝑞𝐷𝐷𝑌𝑌𝐷𝐷𝐶𝐶 , 𝐼𝐼𝐷𝐷𝐷𝐷𝐸𝐸𝐸𝐸, 𝑌𝑌𝑠𝑠𝑠𝑠𝑑𝑑𝑠𝑠
𝐼𝐼𝐷𝐷𝐷𝐷 = 𝐷𝐷𝐷𝐷 → 𝑁𝑁𝐶𝐶𝑁𝑁 = 0
𝑁𝑁𝐶𝐶𝑁𝑁 = 𝐷𝐷𝑌𝑌𝑇𝑇𝑐𝑐.𝐶𝐶𝐴𝐴𝑇𝑇𝑑 𝑌𝑌𝐴𝐴𝑂𝑂𝐴𝐴𝑁𝑁𝑂𝑂𝑇𝑇− 𝐷𝐷𝑌𝑌𝑇𝑇𝑐𝑐.𝐶𝐶𝐴𝐴𝑇𝑇𝑑 𝑁𝑁𝐴𝐴𝐶𝐶𝑂𝑂𝐴𝐴𝑁𝑁𝑂𝑂𝑇𝑇
Project acceptable if IRR Project > IRR min (owners)
Higher IRR project betterConstant price for breakeven
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 83
CSP Performance Indicators
FINANCIAL (Performance)
Levelized Cost of Electricity [$/MWh]
𝐷𝐷𝑌𝑌𝑇𝑇𝑐𝑐.𝐶𝐶𝐴𝐴𝑇𝑇𝑑 𝐶𝐶𝐴𝐴𝐶𝐶𝑂𝑂𝐴𝐴𝑁𝑁𝑂𝑂𝑇𝑇𝐷𝐷𝑌𝑌𝑇𝑇𝑐𝑐.𝐸𝐸𝐴𝐴𝑌𝑌𝑐𝑐𝐶𝐶𝐸𝐸𝑌𝑌𝑐𝑐𝑌𝑌𝐶𝐶𝐶𝐶 𝐺𝐺𝑌𝑌𝐴𝐴𝑌𝑌𝐸𝐸𝐴𝐴𝐶𝐶𝑌𝑌𝑁𝑁𝐴𝐴
𝐿𝐿𝐶𝐶𝐶𝐶𝐸𝐸 = 𝑂𝑂 𝐶𝐶𝐴𝐴𝐶𝐶𝐸𝐸𝐶𝐶,𝐶𝐶𝐶𝐶𝐸𝐸𝐶𝐶,𝑌𝑌𝑌𝑌𝑌𝑌𝐴𝐴𝑑𝑑,𝐷𝐷𝐷𝐷
𝐷𝐷𝐷𝐷 = 𝑊𝑊𝐴𝐴𝐶𝐶𝐶𝐶 = 𝑂𝑂𝐸𝐸𝑞𝑞𝐷𝐷𝑌𝑌𝐷𝐷𝐶𝐶 , 𝐼𝐼𝐷𝐷𝐷𝐷𝐸𝐸𝐸𝐸, 𝑌𝑌𝑠𝑠𝑠𝑠𝑑𝑑𝑠𝑠
Constant price for breakeven
Minimum PPA Price [$/MWh]
min Price at which IRR project ≥ WACCDifferent from LCOE
depends on hourly tariff schemes and usually public numbers relate to average or base PPA price
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 84
CSP Techno-economic Modeling
a number of design objectives shall be considered in the evaluation of CSP plants
and also dependent on the stakeholder
These are all relevant decision criteria and often conflicting
Optimization Trade-offs
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Process 1: Power Plant Nominal Design
SOLAR FIELD SIZE (SM)Mirror area / reflectivity
Receiver Rating / geometryTower height
TES CAPACITYTank specs
Loss CoefficientsMinimum tank levels
POWER BLOCK CAPACITYCycle Layout Design
Live steam and reheat conditions
MULTI-PARAMETER
VALIDATED SUB-COMPONENT THERMODYNAMIC MODELS
Nominal design for specific conditionse.g. Solar positioning and Irradiance (Location)
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Process 2: Annual Dynamic Simulation
Example: Simplified model of a 100 MWe molten salt CSP tower plant with 6h storage (TES) for spot market in Seville, Spain
INPUTS: plant size, weather, TES dispatch-strategy, start-up limitations
OUTPUTS: hourly generation, yield, capacity factor, ...
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Ref. Data: Literature / Quotations / Industry Reports / Industry coop
BOTTOM-UP COST MODEL – LOCATION AND TECH DEPENDENT
Process 3: Techno-Economic Calculations
CAPEX [$]
CPB CSF CTES
Csite CBOP Ctow Ccont
Crec
Cland CtaxCDEV-EPC
CDIRECT
CINDIRECT
OPEX [$/y]Clab Cser Cuti Cmisc
LCOE [$/MWh]IRR [%]
Local Economics(e.g. discount rate)
Market Conditions(e.g. electricity price)
𝐶𝐶𝑛𝑛 = 𝐶𝐶𝑠𝑠𝑠𝑠𝑓𝑓,𝑛𝑛 ⁄𝐶𝐶𝑛𝑛 𝐶𝐶𝑠𝑠𝑠𝑠𝑓𝑓,𝑛𝑛𝑦𝑦𝑛𝑛
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Process 4: Multi-Objective OptimizationTo identify Trade-Off Curves between conflicting objectives
A, B and C are optimal configurations
D is sub-optimal (’naive design’)
Genetic Algorithims used to address:
• Discontinuities / non-linearity
• Local optima
To provide decision-makers with universe set of solutions
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Location Data (i.e. Meteo & economics) - Technical Reports - Industry
OBJ 1: Minimize Investment (CAPEX)OBJ 2: Maximize Profits (IRRPROJECT)
Case study
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Sizing and operation of sub-blocks has a clear impact
PB size, SF size, TES size and dispatch are decisive
Case study
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 92
Case Study: Influence of Price Tariffs
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IC [MWe]
TES[h]
SM[-]
Tower height
[m]
OperatingStrategy
CAPEX[USD×106]
LCoE[USD/MWe]
Fcap [%]IRR [%]
S1 S2 S3A 110 4 1.35 176 Peaking 371.8 106.5 38.6 24.4 -1.2 11.4B 110 14 2.60 235 Peaking 635.0 89.4 74.6 18.7 2.6 10.9C 110 1 1.38 186 Continuous 353.1 99.6 39.5 20.9 0.5 13.3
Optimums are different for different market conditions
One should not compare projects built under different conditions / locations
B CA
Case Study: Influence of Price Tariffs
Agadir, September 5, 2018R. Guédez – Concentrating Solar Power 94
Relevant Effects to consider in CSPThermal Stress
”Internal distribution of force per unit area within a body reacting to applied forces”
Restricted expansionTemperature changesMaterial propertiesThermal gradientsConstraints dependant
Thermal Expansion”Tendency of matter to change in shape,
area, and volume in response to a changein temperature”
Free expansionMaterial propertiesInitial lengthTemperature changes
OUTSIDE
INSIDE
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Agenda© SolarReserve
9:00 – 9:45 Introduction• Solar Fundamentals
• CSP Technology Basis
10:00 – 10:45 CSP Technology, Market & Prospects• Overview of technologies (cont.): projects
• Market outlook, Drivers and Prices
11:15 – 12:30 Thermal Energy Storage (TES)• On the value of TES in CSP
• Review of TES technologies for CSP
2:00 – 3:30 Modeling of CSP Plants with TES• Review on Project Development and Actors
• Power Plant Techno-economic Modeling approach
3:40 – 5:00 Case study: Simulation in SAM
Concentrating Solar Power (CSP)From Solar Fundamentals to CSP Plant Modeling
Dr. Rafael Guédez September 5, 2018
KTH Industrial Engineering and Management
Researcher – Energy Department MASEN Talent Campus, Agadir, [email protected]