Facts of Photovoltaics_PV_ by noidarocker

VIEWS: 12 PAGES: 171

									Facts of Photovoltaics (PV) –
A Promising Alternative Energy Resource

     Dr. Nowshad Amin
     Solar Energy Research Institute (SERI)
     National University of Malaysia (UKM)
Biography

   Born in Chittagong.
   Secondary to College from Chittagong Collegiate School (‘82-’83) &
   Comilla Cadet College (SSC’87, HSC’89)
   Japanese Ministry of Education (Monbusho) Scholarship (Oct1990).
   Japanese Language Course to BS, MS & PhD (Tokyo Institute of
   Technology) in Japan (Oct 1990-March 2001)
   Job at Motorola Japan (Apr. 2001 – Nov 2004)
   Post Doctoral Fellowship at University of South Florida (2002-2003), US.
   Assistant Professor at Multimedia University in Malaysia (Nov 2004-Oct
   2006)
   Assistant Professor at National University of Malaysia (UKM) & Senior
   Associate Research Fellow at Solar Energy Research Institute (SERI)
   from Nov 2006 to date.
Contents

   Introduction
   Renewable Energy Resources
   PV Details
   Application of PV
   Some Facts: Japan and World
   Concluding Remarks
INTRODUCTION



ENERGY
  USE                           RENEWABLE
                                  ENERGY
     FOSSIL
    FUEL AGE               HYBRID
                          FUEL AGE



         PAST   Present       FUTURE
                 times
INTRODUCTION
Energy Demand and Production (Fluid Fossil Fuel)



                     Renewable Energy



                 2008
                                               2015
INTRODUCTION
World fossil fuel reserves
INTRODUCTION
Environmental damage due to fossil fuels (1998)

Total Annual
Loss: $4.35
trillion
Recent Trend of Energy
Renewable Energy Sources




 Wind Energy   Solar Photovoltaic Energy   Solar Thermal Energy


           Focus on Solar Photovoltaic Energy
SOLAR CELLS



                      sunlight




        solar cell               electricity


                     heat
              ENERGY
             RESOURCES
                             Wave and

Solar
            DIRECT SOLARTidal
Radiation
             Photovoltaic – Direct
               Geothermal
               ENERGY        Energy
            Conversion of Sunlight
              Photovoltaic Indirect
               into Electricity
                              Solar
Direct          Stored
                Thermal       Energy
Solar           Solar
Energy          Energy         Nuclear
                               Energy
AVAILABLE ENERGY: LATITUDE & CLIMATE




    FUNDAMENTALS 07
SOLAR CELLS
             ENERGY
           SOLAR THERMAL SYSTEMS
            RESOURCES
           Solar Drying, Solar Hot Water
                                Wave and
           Heating Systems, Solar Space
           DIRECT SOLARTidal
Solar        Heating and Cooling, Solar
              Geothermal        Energy
               ENERGY
Radiation Detoxification, Solar Desalination,
           Solar Refrigeration, Solar Heat
             Photovoltaic Pumping
               Pump, Solar       Indirect
                                Solar
Direct          Stored
                Thermal         Energy
Solar           Solar
Energy          Energy            Nuclear
                                  Energy
SOLAR THERMAL USAGE
Digging Deep Inside PV

   INTRODUCTION
   FUNDAMENTALS OF PV
   PV SYSTEMS
   BUILDING INTEGRATED
   PHOTOVOLTAIC (BIPV)
   DESIGN AND INSTALLATION ISSUES
   EXAMPLE-SIZING OF PV SYSTEMS
FEATURES OF PV


     renewable /
     sustainable
     direct conversion
       quiet
       reliable
     modular
       mW ~ multiMW
     Solar PV Energy

         Advantages                   Limitations
  Majority manufactured        Intermittent power
from silicon - most abundant   Low-energy density
element in the earth’s crust
                               High start-up cost
(28% by weight)
  Environmentally friendly
  Decentralized installation
  Long life (30 years)
  Low maintenance
  Noise-free
  Clean
  Light weight
  Overlap with IC technology
Solar Cell Fundamentals

    1.      What is a Solar Cell?
    2.      Solar Spectrum
    3.      Silicon
         a)    What is a Semiconductor?
         b)    How is Silicon Extracted?
    4.      Solar Cells
         a)    The Photovoltaic Effect
         b)    A Typical Solar Cell Design
         c)    Electrical Model of a Solar Cell
         d)    Limiting Losses in a Silicon Solar Cell
         e)    Performance of a Solar Cell
         f)    Basic Power Output of a Solar Cell
What is a Solar Cell?


    A solar cell is a semiconductor device
    designed to convert sunlight into
    electricity.

    The conversion of light into electricity in a
    solar cell is called the photovoltaic (PV)
    effect.

    Photovoltaics stands for photo, meaning
    “light”, and voltaic, meaning “electricity”.
Solar Spectrum

   The solar spectrum at Earth’s surface in ~ 0.3-2.5-µm range; the
 visible part in ~ 0.4 to 0. 8-µm range,
    The peak sunlight intensity (AM 1.5) is ~1000 W/m2 or ~ 100 mW/cm2
Sunlight Utilization In
Semiconductors

   Convert all sunlight into
electricity

 Design materials to achieve
maximum energy conversion

  Most suitable materials are single
and multiple layer semiconductors

   Silicon is most desirable due to
low cost and optimal match with
solar spectrum
Introduction


  Solar cells convert the incident solar radiation energy into electrical
 energy.
 Sunlight is composed of photons, or "packets" of energy. When photons
 strike a solar cell, they may be reflected or absorbed, or they may pass
 right through. When a photon is absorbed, the energy of the photon is
 transferred to an electron in an atom of the cell (which is actually a
 semiconductor). With its new found energy, the electron is able to escape
 from its normal position associated with that atom to become part of the
 current in an electrical circuit. By leaving this position, the electron
 causes a hole to form.




               The effect of the electric field in a PV cell
How do solar cells work?
p-n Junction

                            Xd
               p-type                     n-type


    anode                                          cathode




                p≈ Na                      p≈Nd


                        -xp 0        xn


                        +
                                Va
Ideal solar cell material


     Bandgap between 1.1 and 1.7eV.

     Direct band structure

     Consisting of readily available, non toxic materials.

     Easy, reproducible deposition technique, suitable for large area
     production.

     Good photovoltaics conversion efficiency.

     Long term stability.
PV EFFECT: BASIC PROCESS AND
LOSSES
   light absorption                             recombination



   transport of charge                    Egap                                         hν
   carriers

   charge separation &                                                       generation


   collection                                 1.6               solar spectrum
                                                                convertible by c-Si cell


                          power [W/(m2.nm)]
                                              1.2
   power generation
                                              0.8
   (energy dissipation)
                                              0.4

   final recombination                        0.0
                                                    400   800    1200 1600 2000             2400
                                                                wavelength [nm]
OPERATING PRINCIPLE SOLAR CELL



       _                              anti-reflection coating
                                      front contact
                                      n-type semiconductor

                       electron (-)   p-type semiconductor
       hole(+)   generation


                      recombination
                                      back contact
      +
CURRENT – VOLTAGE
CHARACTERISTIC OF A SOLAR CELL




                     current→
          dark                                          Vmax
                                    voltage →                     open
                                                                 circuit
                                                                voltage
                     Imax
                                                         Pmax
       illuminated
                                short circuit current
Solar Cells Parameters

                   qv

        Ι = Io[e   Akt
                         − 1] − IL
  Io is the reverse saturation current
  A is diode quality factor
  IL is the light generated current
  t is depth of the semiconductor material
  from the surface of incident light
Solar Cell Parameters (cont.)

   Short circuit current densities
   Isc=-IL
                            I   sc
           J   sc    =
                                A
   A is area of the solar cells
   Isc is the short circuit current
Solar cells Parameters (cont.)



  Open circuit voltage, Voc
                   ⎡ kT ⎤ ⎛ I sc       ⎞
         V oc   = A⎢    ⎥ ln ⎜ I o + 1 ⎟
                   ⎣ q ⎦ ⎝             ⎠
  Fill Factor, FF
                     V m Im
                FF =
                     V oc I sc
Solar cell parameters



  Efficiency, ŋ
                   FF × Voc × Isc
                η=                × 100%
                       Pin
    As the total radiated power incident on the cell Pin is
    100, the efficiency reduces


                  η = VocJscFF
PV Voltage, Current and Power




                                Imp × Vmp
                           FF =
                                Isc × Voc

                        ImpVmp IscVocFF
                     η=       =
                          Ps       Ps
 P max = Imp × Vmp
 EFFICIENCY AND YIELD



                    maximum electric power
 efficiency    =                               at Standard Test
                   incident illumination power
                                               Conditions (STC)

                       electric energy

energy yield   =    incident solar energy    under practical
                                             conditions


  STC: 25 oC, air mass (AM) 1.5, 1000 W/m2, ⊥
EFFICIENCY IDEAL AND PRACTICAL
CELLS

ideal cells
loss factor                           remedy
- spectral mismatch   η≤30%   - multicolour (tandem) cells   η≤85%
- recombination               - concentration

practical cells and modules: add
- excess recombination
- shadowing & reflection
- transmission                                example:
- resistance                                  multicrystalline
- non-optimal band gap(s)                     silicon cell (15%)
Study Details: CdTe Thin Film Solar Cell
                           hν


 Corning 1737

 ITO (2500Å )
     CdS                                       MOCVD法 (600Å )
                      Ag
                             CdTe              CSS 法
                                                                膜質改善
                                              (4~ 7μ m )
                             Carbon                             CdCl2 処 理
                                               印刷法
                                                              p 型化
                                Ag            (20μ m )
                                                            (Cu-Doping)

                                +
                Schematic View of the CdS/CdTe Solar Cell
                Schematic View of the CdS/CdTe Solar Cell
                           Objectives of this Study
                                                                      Cd T e Th ickn ess Red uctio n to 1µm
Cd Te A bso r ptio n Co efficien t: 2x10 4 cm -1         hν
                                                                                                      Rec ombi nat ion
                                                                                φ2 - φ1               S tate s
                                                                           CB                      Bac k Contac t
      Over 90% o f In cid en t                      Co r nin g 1737        EF
      Sp ectru m Ab sor b ed
       in 1 µ m-Cd T e layer                            TCO                VB
                                                                             Cd S            Cd T e
                                                         Cd S
                                               Ag          Cd Te
                                                              ZnTe      Heter o S tru ctu re at Back S ur face
                                                              Ag
       In sertio n of T extur ed TC O                                            V acu u m Level

                     Light
                     TCO                                                        E lectr o n F lo w
                                                                                                            2. 26e V
                                                                                               1. 44e V
      Diffraction                Diffraction
                                                                                  2 .4 1eV
        Light Absorption Layer
                                                                                   Cd S        Cd T e      Zn T e
                                          Achievements of the Study
                                          Achievements of the Study
CdTe 光吸収係数は 2x104 cm-1 、 入射光の 90%を 1µm で吸収                                                          1 µmまで薄膜化

  1.2 µm-CdTe 太陽電池の場合、変換効率は 11.5%。

  Textured SnO 2 の導入により、 0.6-µm CdTe 太陽電池の場合、変換効率は 11.2%。


                                                                                                                NREL (15.8%)
                                          16
              Conversion Efficiency [%]

                                                                           Matsushita
                                                                                                      U. S. F
                                                                             (16%)                   (15.8%)          T. I. T.
                                                                                                                     (15.3%)
                                          14                                             T. I. T.
                                                                                        (14.7%)
Present
Position                                  12
                                                           ITO


                                          10     Textured TCO

                                                   ITO
                                                                                                                T.I.T.
                                                                                                                Others
                                           8
                                           0.0       1.0         2.0     3.0    4.0    5.0            6.0          7.0           8.0
                                                                       CdTe Thickness [µm]
What is a Semiconductor?

    Semiconductors absorb sunlight to create electrical
    current

    A semiconductor has an electrical conductivity in
    between that of a metal and an insulator.

    Most common semiconductors for PV cells include:
      Silicon (Si)
      Gallium Arsenide (GaAs),
      Copper Indium Diselenide (CuInSe),
      Cadmium Telluride (CdTe).

    Silicon is also the material of choice in the integrated
    circuit manufacturing
How is Silicon Extracted?

    Raw silicon is first extracted from common sand. A
    series of chemical steps refine it until the purity
    level reaches 99.9999999 %. Thus, for every ten
    billion atoms, only one non-silicon atom can be
    permitted.

    Crystalline silicon is used in most solar cells.

    To create a crystal, two methods are used:
      Czochralski (CZ) process,
      Float-zone (FZ) process.
   CZ dominates the market.
The Czochralski Process
   A seed of single crystal silicon contacts the top of a molten mass
 (1421ºC) of purified silicon. The seed crystal is slowly raised (less than 10
 cm per hour) and rotated. As the crystal rises imperceptibly from the
 melt, silicon freezes on its surface, extending the size of the single crystal.




                                           Silicon ingots are "grown" from the
                                        purified molten silicon. Slices of the
                                        ingot - ranging from 100mm to 300mm
                                        (4 to 12 inches) in diameter with a
                                        thickness about 1/30th of an inch thick
                                        (approximately that of a credit card )
                                        are cut from this crystal. The slices are
                                        called "wafers."
The Photovoltaic Effect

 Described simply, the PV effect is as
   follows:
   Light which enters a PV cell imparts
   enough energy to some electrons      covalent                      free electron
   to free them from the silicon atoms. bond                          e-
                                                              created hole
                                                          +
   The missing electron in the bond is                        (missing
   called a hole. In other words,            Si atom
                                                              electron)
   incident light has created a free
   electron and a hole.
                                                                Photon
   The generation of electrons and holes by light is the central
   process in the PV effect, but it does not itself produce a current.

   A built-in-potential barrier in the cell acts on these electrons to
   produce a voltage, which can be used to derive a current
   through a circuit.
A Typical Solar Cell Design
  Solar cells comprise 2 major regions:
       A P-region conducting positive charges (holes),
       And an N-region conducting negative charges (electrons).

  A typical solar cell has several layers:
      A conducting grid on the top surface,
      An antireflection coating to reduce reflections of the incident light on
   the cell,
      A semiconductor with the P and N regions
      And a back metal contact electrode.
Electrical Model of a Solar Cell


                               A PV device can be modeled
                            as an ideal diode in parallel
                            with a light-induced current
                            generator, ISC.
      ID
                              Rsh: shunt resistance, mainly
                            due to crystal imperfections.

                               Rs: series resistance, arises
                            from the bulk conductivities of
                            the layers and from the
                            contacts.
     Limiting Losses in a
     Silicon Solar Cell


                               Sunlight has not enough
                             energy to separate electrons
                                                                Optical Losses

  Sunlight:100mW/cm2
                              Excess energy has heat
Cell Output:   16.6mW/cm2             losses



Why a solar cell                Collection efficiency



 is not 100%                                                    Material
                                  Thermalization
                                                                Losses
   efficient?               Metallic Losses


                                                            → Solar efficiency
Performance of a Solar Cell

 The performance of a solar cell is function of:

      Sunlight and climate conditions,
      Angle of incidence,
      Wavelength of the light,
      Polarization,
      Surface area of the solar cell.
Basic Power Output of a Cell

    Voltage of the electric current: 0.5 Volts.
    This results from the voltage across the P/N
    barrier layer of the solar cell.

    Current of a solar cell: proportional to the amount
    of radiation incident on the solar cells and the
    number of electron-hole pair created
    ~ 30-40 mA/cm2.

    Efficiency (ratio of electric power produced by a
    cell at any instant to the power of the sunlight
    striking the cell):
    ranges up to 28% (lab) but typical is ~ 15%
    (manufacturing).
     Solar Cell System Configurations

1.   PV Modules and
     Arrays




2.   PV Solar Electric
     Systems
Solar Cell System Configurations


One solar cell produces only 0.5 V and
30mA/cm2, which isn't enough power for most
applications.

To increase power output, cells are electrically
connected together.

Solar cells are connected in series to increase
the voltage.

Solar cells are connected in parallel to increase
the current.
PV Modules and Arrays

   Solar cells connected in series increases voltage. The positive lead from
 one cell is joined to the negative lead of the next cell and so on.

    Solar cells connected in parallel increases current. A common lead
 joined all the positive terminals and another lead joined all the negative
 terminals.




       Vtotal = V1 + V2 + V3 + …                Vtotal = V1 = V2 = V3 = …
        Itotal = I1 = I2 = I3 = …                Itotal = I1 + I2 + I3 + ...
PV Modules and Arrays

  A group of solar cells put together is called a photovoltaic module.

   Solar cells are combined to form a module to obtain the voltage and
current (and therefore power) desired.
For example, to form a 12-volt module, 24 solar cells have to be connected
in series.
                              A photovoltaic array is a group of
                           photovoltaic modules put together to generate
                           electricity.

                             A PV array may consist of one module to
                           thousands of modules. The output of the array
                           may vary from a few watts to tens of
                           Megawatts depending on the number and
                           output of the modules.
Typical Solar Module

   Cells are interconnected and packaged in a weatherproof module.

   The cells are encapsulated in a material like silicone or ethylene-vinyl
 acetate (EVA) and covered by a tempered glass sheet.




   The module is sealed into a metal frame (typically Al) complete with
 mounting holes so that the module can be attached to rack or building
 assemblies.
PV Modules and Arrays




                PV modules are very versatile. They can be
              mounted in a variety of sizes and applications. For
              example:
                    On the roof or awning of a building,
                    Building-integrated PV such as PV shingles,
                  which replace conventional roofing shingles (a),
                    Water pumping (b),
                    Communications (c),
                    Large-scale utility power (d),
                    And roadside emergency phones (e).
PV Solar Electric Systems

 Photovoltaics converts light energy directly into an electric current that
 can either be used immediately or stored for later use, such as in a battery.
                                                  A solar cell produces direct
                                               current (DC), but most of the
                                               appliances at home require
                                               alternating current (AC).

                                                 A device called an inverter
                                               converts a solar cell’s DC into
                                               AC.

                                                 DC: current always flows in
                                               the same direction.

                                                 AC: the direction of the
                                               current alternates.
PV Solar Electric Systems

   The solar electricity can also be integrated into an electric utility's grid
 system.

   During the day, you can complement the power grid with photovoltaic
 energy.

  Benefits:
    Reduced power bills
    Increased value of the
  residence
    Positive environmental
   contribution
Solar Cell Manufacturing
Solar Module Manufacturing
Types of Solar Cells
Types of Solar Cells in Market Share
World PV Research Growth
Multijunction Solar Cell

                           Spectrum of sunlight
                           split and distributed
                           over a variety of
                           semiconductor
                           materials by a prism.
                           Each semiconductor
                           material was
                           selected in which
                           would best match
                           each portion of the
                           spectrum
PV Cell to Module
Configuration of Solar PV System
PV TECHNOLOGIES

• commercial
       - wafer-type crystalline silicon (c-Si; mono & multi)
       - thin-film amorphous silicon (a-Si;
         incl. silicon-germanium and microcrystalline silicon)
• pre-commercial / pilot production
       - thin-film cadmium telluride (CdTe)
       - thin-film copper-indium/gallium-diselenide (CIGS)
• laboratory
       - sensitized oxides (a.o. dye cells)
       - organic cells (o.a. polymer cells)
PV TECHNOLOGIES
example sensitized*) oxide cell (not to scale)
                                 glass/plastic
                                 transparant conducting oxide +
                                 (counter electrode)

                                  electrolyte
                                 nanocrystalline, porous TiO2
                                  transparant conducting oxide
                                  (photoelectrode)

                                      dye

                                   TiO2

                                    *) with dye, polymer or
                                    inorganic absorbers
PV TECHNOLOGIES & EFFICIENCES

                 30                                                                                wafer-based c-Si cells

                 25                                                                                thin-film CIGS cells

                                                                                                   thin-film CdTe cells
efficiency (%)




                 20

                                                                                                   thin-film a-Si cells (stable)
                 15

                                                                                                   wafer-based c-Si modules
                 10
                                                                                                   thin-filmGIGS modules
                  5
                                                                                                   thin-film a-Si modules
                  0                                                                                (stable)
                      1955

                             1960

                                    1965

                                           1970

                                                  1975

                                                         1980

                                                                1985

                                                                       1990

                                                                              1995

                                                                                     2000

                                                                                            2005
                                                    year
PV TECHNOLOGIES & EFFICIENCES
        CATEGORY         GROUP      MATERIAL          TYPE         RECORD        TYPICAL
                                                                   EFFICIENCY    MODULE
                                                                   LAB CELLS     EFFICIENCY
                                                                   (%)           (%)
        inorganic      IV           (Cz + FZ) sc-Si   wafer        25            13-16
        semiconductors
                                    mc-Si + Si        wafer        20            12-14
                                    sheets

                                    (poly)crystalline wafer+film   16            (8-10)
                                    Si films
                                    a-(Si,Ge):H       thin film    14 (tandem)   5-9 (stable)
                                    and µc-Si
                         III-V      GaAs family, InP, wafer+film   25 (single)   20-22
                                    GaSb, a.o.                     30 (tandem)   (space)
                                                                   33 (conc.)
                         II-VI      CdTe, CdS, a.o.   thin film    16            6-9

                         ternary    Cu(In,Ga)(Se,S)2 thin film     19            8-11

        organic                     polymer           thin film    3             ---
        semiconductors
                                    molecular         thin film    5             ---

        sensitized       organic    dye/TiO2 a.o.     thin film    11            ---
        oxides
                         inorganic CIS/TiO2 a.o.      thin film    ?             ---

        other            hybrid     various
THIN-FILM SOLAR CELL:
EXAMPLE a-Si
THIN-FILM SOLAR CELLS:
INTERCONNECTION IN A MODULE




       monolithic interconnection in an a-Si module
SERIES CONNECTION IN A MODULE:
EFFECT OF PARTIAL SHADOWING




                           Demosite
MODULE BUILD-UP:
ENCAPSULATION OF SOLAR CELLS
MODULES BASED ON WAFER
TECHNOLOGY: CELL DENSITY
COMMERCIAL PV MODULES:
TYPE, SIZE, COLOUR AND FRAMING
COMMERCIAL PV MODULES:
FRAMELESS MODULES (LAMINATES)
COMMERCIAL PV MODULES:
PARTLY TRANSPARENT MODULES
INSULATED (PV) GLASS
PRECOMMERCIAL PV MODULES:
TRANSLUCENT MODULES




                            window
                            element with a-
                            Si cells
COMMERCIAL PV MODULES:
FLEXIBLE MODULES
roofing element with
flexible a-Si module
  MODULES BASED ON WAFER
  TECHNOLOGY: SPECIALS
BP SOLAR




           coloured PV cells
           note: (15-30% reduced output)
CUSTOM-MADE PV-MODULES




                      PV glass brick



  triangular module
CUSTOM-MADE PV-MODULES




                    “solar path”
CUSTOM-MADE PV-MODULES




                         solar chess
BIFACIAL PV MODULES
MODULES BASED ON WAFER
TECHNOLOGY: NEW DEVELOPMENTS

   conventional




          PUM




 Pin-Up Module (PUM):
 all interconnections at the back of the cells
THIN-FILM MODULES:
NEW DEVELOPMENTS




                         dye-sensitised solar cells
                         (laboratory/pre-pilot phase)




           price label
  PV MODULES & SYSTEMS:
  RATING
• module and system rating in watt-peak (Wp)

• e.g. a 50 Wp module generates 50 watt of electrical power at
Standard Test Conditions (STC)

• in addition, or alternatively, the power under realistic
conditions may be given (which is usually somewhat lower)

• in some cases also the actual energy production under
practical conditions (over a certain period of time) will be given
or guaranteed
          note: Standard Test Conditions are 25oC, 1 sun = 1000 W/m2,
                AM 1.5, normal incidence)
EFFECT OF OPERATING CONDITIONS

• temperature
      - module efficiency decreases with temperature:
        typically 0.2-0.5%/K (relative), depending on module
        technology

• light intensity
        - module efficiency decreases with light intensity:
          generally weak dependence from 1 to 0.1/0.2 sun,
          below 0.1/0.2 sun strongly dependent on module
          technology and type
             note: nameplate rating generally at Standard Test Conditions
             (STC; 25oC, 1 sun = 1000 W/m2, AM 1.5, normal incidence)
PHOTOVOLTAIC SYSTEMS – Standalone System



              PV Panel


                                     Lamps


        Charger                       TV


    Battery                          Radio
    Storage
PV SYSTEMS


 stand-alone
   systems

     consumer products
     telecom
     leisure
     water pumping
     lighting & signalling
     rural electrification
     etc.
PV SYSTEMS



 energy yield dependent on:

 - solar insolation (location)
 - system power rating (in watt-peak, Wp)
 - “system efficiency” (performance ratio):
      module efficiency under practical conditions
      inverter, regulator, battery (if applicable) & cable
       losses, etc.
     system availablitity
    STAND-ALONE PV SYSTEMS

charge regulator
- protect battery from over- and underloading
- prevent reverse current from battery to module when dark



battery
- simple lead-acid (“car battery”) to advanced solar battery or NiCd, etc.
- provide short- (day), mid- (week-month) or long-term (season) storage
- operate for long period (>4 years) if properly maintained
- requires replacement within module lifetime
STAND-ALONE PV SYSTEMS:
EXAMPLE SOLAR HOME SYSTEM

    typical energy yield 50 Wp solar home system:
    (assume 2000 kWh.yr insolation)
    - net module production: 70 kWh/year = 200 Wh/day
    - including storage losses = 150 Wh/day


    energy services provided:
    - 3 x 8 W TL lamp x 3 hrs = 72 Wh/day
    - 1 x 40 W B/W TV set x 2 hrs = 80 Wh/day
    - TOTAL = 152 Wh/day
STAND-ALONE PV SYSTEMS




                         Brazil
STAND-ALONE PV SYSTEMS




                         PV water pumping in India
STAND-ALONE PV SYSTEMS




                         lndia
PHOTOVOLTAIC SYSTEMS – Grid
connected

                       DC/AC
     PV Panel
                               Lamps   Utility Grid


                                TV




                Load
GRID-CONNECTED PV SYSTEMS


                                                             Japan
 ground-based
 integrated
  • roof-top & façade
  • sound barriers
  • etc.



                   (typical yield: 750-1500 kWhe/kWp·year,
                             depending on location)
GRID-CONNECTED PV SYSTEMS




                        key components in a
                  grid-connected PV system
GRID-CONNECTED PV SYSTEMS




  CIGS rooftop PV system (NL)
GRID-CONNECTED PV SYSTEMS




             2.3 MWp PV at the “Floriade” in NL
                      (horticultural exhibition)
GRID-CONNECTED PV SYSTEMS




          A residential area in the Netherlands
    GRID-CONNECTED PV SYSTEMS

inverter
- efficient DC/AC conversion
  (typical average efficiency ≥90%)
- maximum power point tracking (MPPT)
- high-quality output
  (low harmonic distortion, etc.)
- safe and robust operation
  (no island operation, protection against
   indirect lightning strikes, etc.)
- long lifetime
GRID-CONNECTED PV SYSTEMS


building integrated PV at ECN
COOLING
THERMAL EFFECT ON EFFICIENCY




                               ECN
COOLING
THERMAL EFFECT ON PV

      Mind local shading and possible hot spots!
COOLING - THERMAL EFFECT ON
SURROUNDING MATERIALS

  The temperature difference between PV and
  ambient up to 40°C (in summer up to 70°C)
  insulated PV at the rear side - higher
  temperatures
  air gap at the rear side preferable
  too high temperature: roofing material can melt
  (bituminous materials!)
  tear, leaking or breaking of the PV laminate
  can appear
  expansion space usually available
POWER & HEAT
PRINCIPLES OF PV-THERMAL




      combined generation of heat and electricity
POWER & HEAT
AIR and FLUID FLOW TRANSFER
FLAT ROOFS: INTEGRATION OPTIONS

 support
 structure on
 the roof


 PV parasol



 shed or
 saw-tooth
 roof
                                  M.ART
SLOPED ROOFS: INTEGRATION
OPTIONS

mounted over tiles (stand-
off) or integrated


fully covered roof




PV as roof tiles
PV- ventilated (air gap
at the rear)
                             M.ART
FAÇADES: INTEGRATION OPTIONS


fully or partly
façade
integrated



PV / glass conservatory




balcony breast wall
AWNINGS: INTEGRATION OPTIONS



independent of building
  envelope
fixed or movable

incorporated in building envelope as
a curtain wall


canopy
 SUN PORCH, VERANDA, ATRIUM
 INTEGRATION OPTIONS

in flat or sloped roof
limited roof load




special case: membrane
or network construction
FLAT ROOFS
mounting options
 Support structure on the roof
 Gravity mounted or fixed mounted
 Optimal orientation & tilt
 Limited covered area due to mutual shading
FLAT ROOFS
support structure
metal support structure
alternatives: concrete, plastics




                                   GROUND-BASED PV ARRAYS
                                   • similar concept as for roofs
                                   • metal support structure on
                                     concrete foundations
                                   • good accessibility
                                   • possibility of sun tracking
                                   • high land consumption
                                   • theft problem
FLAT & SLOPED ROOFS: PV
PARASOL
  PV covered roof construction as a parasol reduces
  heat load
  with or without water-retaining function
  SLOPED ROOFS
  mounting options
STAND-OFF
  support structure
  suitable for retrofits
  cooled from the rear
  easily mounted and
  replaced
INTEGRATED
  good integration
  possible
  no mutual shading
  mind water tightness
  and ventilation
FAÇADES
mounting options

 •might be cost-effective
  (replaces traditional cladding material)
 •risk for damage on the ground floor
 •not the optimal tilt
 •aesthetically challenging
COMBINED FUNCTIONS
SHADING DEVICES

ideal for PV
modules integration
suitable both for
new and existing
buildings
excellent
combination of
passive cooling,
daylighting control
and energy
production
OTHER OBJECTS

  sound barriers
  bus stops
  roofs of railway platforms or bus
  stations
  along the railways
  information boards, etc.
COMBINED FUNCTIONS
PV-THERMAL

Hybrid collectors with medium:
        AIR or WATER


  •cooling PV improves efficiency
  •heat can be used
    −in summer (hot water)
    −in winter (space heating)
   •attractive in case the
    available roof surface is limited
COMBINED FUNCTIONS
NATURAL LIGHTING
SKY LIGHTS
   PV at the South side
   light from the North
ideal for workshops

TRANSPARENT or
TRANSLUCENT PV
• opaque solar cells laminated in
  double glass
• space between cells 1-3 cm
• diffuse or tempered light
• interesting shadow patterns
  ORIENTATION & TILT
  location, building & planning
  constraints
orientation &
      tilt
influences the yield
considerably
southern orientation
preferable (northern
hemisphere)
count with the right
orientation while
planning a
residential area
mind possible
mutual shading

                                  M.ART
ORIENTATION & TILT
sun tracking

Sun tracking system

•movable along one axis (horizontal)
•movable along two axes
•sun tracking sensor
•lamellas with integrated PV modules
•integrated in a façade
•cost-benefit ratio questionable




      DESIGN PARAMETERS 02
RESIDENTIAL & COMMERCIAL
BUILDINGS
PV INDUSTRY



                    400                          average market growth 1981-2001: 24%
                                                                                                                     other
module production




                    350                                                1996-2001: 38%
                                                                                                                     Europe
                    300
                    250                                                                                              Japan
     (MWp)




                    200                                                                                              USA
                    150                                                                                              total
                    100
                     50
                      0
                          1976

                                 1978

                                        1980

                                               1982

                                                      1984

                                                             1986

                                                                    1988

                                                                           1990

                                                                                  1992

                                                                                         1994

                                                                                                1996

                                                                                                       1998

                                                                                                              2000
                                                                    year

           source: P.D. Maycock / NCPV Hotline



                     BUILDING INTEGRATION 18, 22, 24
PV INDUSTRY

                      The Top Ten Solar Cell Producers in 2001
                                   (Source: PHOTON International)



    Sharp                                                                                          74,0
    BP Solar                                                                      54,4
    Kyocera                                                                       54,0
    Siemens & Shell Solar                                                  48,3

    AstroPower                                           26,0

    RWE Solar                                        22,7

    Isofoton                                      18,7
                                             16,0
    Sanyo
                                           14,0
    Mitsubishi
                                           13,5
    Photowatt

                             0,0    10,0      20,0          30,0   40,0    50,0      60,0   70,0      80,0

                                                                      MW



   BUILDING INTEGRATION 22
PV SYSTEMS:
PRICE REDUCTION
price reduction of PV systems requires:
• economy-of-volume
• improved & new technology

price level in 2007:
(turn-key grid-connected rooftop systems):
• 4~5 US$/Wp

long-term perspective:
• turn-key system price <1 US$/Wp
ENVIRONMENTAL ISSUES


   energy pay-back time systems
         (grid-connected systems)
     now 4-8 years (EU)
     future (<10 years) 1-2 years
   materials consumption
    avoid hazardous or scarce materials
    some alternatives required (for Ag, e.g.)
    recycling to be developed further
SOCIAL ISSUES


    rural access:
    - 2 billion people without access to electricity grid
    - PV provides electricity (energy services) in any
       affordable amount
    - need for financing options
    - need for infrastructure (after sales, etc.)
    - PV may be used as tool in development programmes
    - PV is only sustainable energy technology for general use




   BUILDING INTEGRATION 25
SOCIAL ISSUES



   job creation:
   - high value jobs
   - quantified by European PV Industry Association
     EPIA and Greenpeace
   - possibilities for substantial added value in
     developing countries




    BUILDING INTEGRATION 25
PV ADDED VALUE


 PV is more than just a kWh-
 generator:
 - is also building element
 - provides green power
 - enables self-sufficiency in power generation
 - can be used everywhere (all countries, all
 locations)
 - can be designed in any size
 - etc.
EXAMPLE - SIZING OF STANDALONE
SYSTEM

   Step 1 – Determine the Load Available
   Sunlight, PV Array Size and Battery
   Bank Size
   Step 2 – Calculate PV System Costs
EXAMPLE - SIZING OF STANDALONE
SYSTEM
EXAMPLE - SIZING OF STANDALONE
SYSTEM
EXAMPLE - SIZING OF STANDALONE
SYSTEM
Recent Trend of Energy Industry
        World Shipment of Solar Cells

                                    Japan   U.S.A.   EU   Others
               3000


               2500


               2000
SHIPMENT(MW)




               1500


               1000


                500


                  0
                      1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
                                                 YEAR
World Shipment of Solar Cells
(by Manufacturers)

                Isofoton (Spain)

        SunPower (Philippines)

         Schott Solar (Germany)

               MOTEC (Taiwan)

      Mitsubishi Electric( Japan)

                  Sanyo (Japan)

                Suntech (China)

                Kyocera (Japan)

               Q-Cell (Germany)

                   Sharp (Japan)
   Annual
 Production
                                    0   100   200   300   400   500
 (MW/Year)
World Shipment of Solar Cells

                             single c-Si   cast Si   Si ribbon   Si thin film   CIS   CdTe
                 3000

                 2500
Production(MW)




                 2000

                 1500

                 1000

                 500

                   0
                         83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 0 1 2 3 4 5 6
                                                         Year
                        Production of Si thin-film solar cells: 98MW for 2006
World Shipment of Thin-Film Solar Cells
                                                   S i T h in F ilm     C u (In G a )S e 2   C dT e

                                      180
                                                                                             CdTe: 68MW
                                      160
P R O D U C T IO N (M W / Y E A R )




                                      140
                                      120                                                     CIS: 4.9MW

                                      100
                                       80
                                       60
                                       40
                                                                                                       Si: 98MW
                                       20
                                        0
                                            2001   2002          2003            2004           2005       2006
                                                                        YEA R
                            Cumulative PV System

                                             Japan    Germany     USA

                            1600

                            1400
Cumulative PV System (MW)




                            1200

                            1000

                             800

                             600

                             400

                             200

                               0
                                   97   98   99   0    1    2     3     4   5   6   7
                                                           YEAR
Applications
ECO HOUSE (UKM)
Mankind will need additional 20TW by the mid-21st century.
   Only Photovoltaics will meet this challenging target.
Thoughts to share

 Let’s create public concern with various
         PV activities in Bangladesh.

 No Luxury before ensuring Power for All.

 Our PV-Chain could assist Energy Demand
        of Bangladesh from now on.
       Cont…..
Let’s think about our
 coming generation
   with Solar…..

       Solar Energy Research Institute
        National University Malaysia
        Website: www.eng.ukm.my
         Email: nowshad@eng.ukm.my

								
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