Standards for PV metrology IEC and IEC Stefan Winter, PTB German member of IEC TC82-WG2

Transcription

1 Standards for PV metrology IEC and IEC Stefan Winter, PTB German member of IEC TC82-WG

2 Overview o Demand for high accuracy solar cell calibrations o Standard Test Conditions o DSR Method o The new PTB setup: Advantages and disadvantages o International Comparisons => WPVS

3 Magnitude of Solar Energy Sun radiation onto earth corresponds to 120,000 TW Total human energy need today: 13 TW Solar energy is the only kind of energy that can solve the earth s energy problems! Sources: G.W. Crabtree and N.S. Lewis, Physics Today, March 2007 ; and Prof. Eicke Weber, ISE

4 Land requirements for PV You need 6 areas of 340x340 km² (1800 kw/j) with actual available solar modules (15 % eff.) to get 20 TW Source: G.W. Crabtree and N.S. Lewis, Physics Today, March 2007 sowie Prof. Eicke Weber, ISE

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8 Energetic amortization of PV systems Study for the German Federal Ministry of Economics, Technology and Labor: Energetic Amortisation time in years sc-si system 2,2 pc-si system 2,3 a-si system 3,2 CIS System 2,1 Including solar modules, mounting system, frames, cabels, inverter, auxiliary energy, operating supplies Briem et al, Study Lebenszyklusanalysen ausgewählter zukünftiger Stromerzeugungstechniken made by Institut für Energiewirtschaft und Rationelle Energieanwendung an der Universität Stuttgart, Deutsches Zentrum für Luft- und Raumfahrt, Institut für Technische Thermodynamik, Stuttgart, Forschungsstelle für Energiewirtschaft e. V., München and the Lehrstuhl für Energiesysteme und Energiewirtschaft Published by the VDI-Verlag in 2004 (Page 133, Tab. 7-15)

9 Future trends

10 Economic Impact of Measurement Uncertainty for Photovoltaics System prices for end customers in Euro / Watt Prices in Euro/Watt Yearly worldwide newly installed PV Power / GW New PV installations * Source of data: Source of data: EPIA (European Photovoltaic Industry Association) and for 2015 according to IHS market research institute Financial uncertainty = Global annual installation Price Uncertainty 2012: Financial uncertainty = 30 GW/year 1.7 /W 1 % = 500 M /year A measurement uncertainty of 1% leads to a financial uncertainty of 500 M /year High demand for high accuracy solar cell calibrations Solar parks are financed from banks, who add the financial uncertainty arising from measurement uncertainty to the total amount to be financed. A low uncertainty leads to competitive advantage.

11 Metrological Integration Calibr.-Costs in Euro Uncertainty (k=2) > 0,5 % > 1,5 % Calibrationlaboratories IEC PV - Industry The pure measurement time for the calibration of one solar cell is about 24 hours.

12 PV calibration chain λ Laser Cryogenic radiometer Φ, P Current and Voltage Measurement < 0,01% Legende: Source Detector Standard Detector s Φ(λ) 0,1% λ, Ε Facility Monochromatic + Bias radiation DSR Facility Reference solar cell s (λ), Ε Ι STC 0,5% Ε Solar simulator IV-Characteristics PV-Module Ι STC Oerlikon

13 Standard Test Conditions Reference solar spectrum AM1,5 Irradiance E STC = 1000 W/m² Cell-Temperature (25 C) Angular distribution important, but not defined The calibration procedure must take into account these STC according to IEC

14 EMRP Project PhotoClass From Standard Test Condition to Climate Zones From Peak-Power to Energy rating Definition of new Standards (IEC series) Task of PTB: Metrological background Building up measurement capabilities for new measurement tasks

15 Metrological background Reference solar spectrum AM1.5 according to IEC :2008 Spectral responsivity of different solar cells Spectral irradiance Eλ / mw m -2 nm AM1.5 (IEC :2008) Wavelength, λ / nm Absolute spectral responsivity, s / AW -1 0,8 0,6 0,4 0,2 0,0 Photon energy / ev η = 100% a-si GaInAs CdTe GaInP c-si Poly-Si CIS Ge Component Cell Wavelength / nm Photocurrent: I λ s( λ)dλ = E, Norm ( λ)

16 DSR-Method Differential Spectral Responsivity IEC Bias radiation E b Modulated monochromatic radiation, measured with Ref.-PD E(λ) 10 8 Irradiance E 6 4 : Monochromatic + bias radiation 2 : Bias radiation ms 60 Time t Solar cell I b + I sc (λ, E b ) DC-Multimeter + Lock-In-Amplifier

17 Design of the new Laser-DSR Facility Electronic x,y,z-table Climate Chamber Φ-θ-Goniometer Biasradiator Compact Array Spectroradiometer Optics (Lenses, Apertures, Monitor phodiode) Monochromator Pulse-to-CW Convertor (Fiber) Lasersystem (Ti:Saphir Laser, OPO, SHG, THG, FHG) Chopper

18 Calibration objects Reference solar cells Component solar cells Industry solar cells Absolute spectral responsivity, s / AW -1 0,8 0,6 0,4 0,2 0,0 Photon energy / ev η = 100% a-si GaInAs CdTe GaInP c-si Poly-Si CIS Ge Component Cell Wavelength / nm

19 Determination of the Electrical Power using IEC Current I / ma V MPP V OV P = U I Electrical Power P / mw I sc I MPP P MPP = P elektrisch Maximum- Power- Point mv 600 Voltage V Energygeneration Energyconsumption

20 Realisation und maintainance of the World Photovoltaic Scale PTB NREL AIST TIPS

21 Conclusion and Outlook o PV is a 50 billion/year market o DSR method takes the IEC into account and is explained in IEC o PTB ensures the traceability of reference solar cells o PTB has developed the next-generation of the DSR facility with world-wide lowest measurement uncertainty: LASER-DSR o It is a multipurpose spectral comparison facility. s = s(λ, E, f Chopper, T, x, y, z, ϕ, θ) o One application: Energy rating o Future development: Calibration of reference modules