Photovoltaic solar systems

Transcription

1 Energy and sustainable devlopment Photovoltaic solar systems Stéphan ASTIER

2 Photovoltaic Solar Systems

3 Renewable energy ressources on Earth by year Réf. : human activities : GWh Moon Earth marées GWh 45% : sun GWh noyau 0, GWh GWh transformed In heat et rayed 30% directly re-emitted to space 25% converted at surface and atmosphère Hydrocarbon fossil = stored solar energy - Hydro cycles (88%) GWh - wind, waves GWh Photosynthesis (0,24%) 10 9 GWh Bernard MULTON 27 years = 1 day

4 The Sun R = km M = 1, kg Température on surface K Total emitted power : 3, kw (6MT/s) At earth level (150 M km) Solar Constant :Esc = 1367 W.m-2 Average energetic flux received by Earth : 1, kw Solar radiations 0,2 μm (ultra-violet) < λ < 4μm (infra-red) 0,4 μm < λ visible < 0,78 μm (infra-red) 97,5% of energy between 0,2 μm et 2,5 μm maximum at 0,5 μm (jaune-vert à 5800 K)

5 Atmosphere modifications Standard Atmosphère for reference : 7,8 km vertical thickness plane and stratified gaz layers at P=1.013mB et T=0 C m Air Mass number : = P sin A exp( out of atmosphere, at high altitude : AM0 conditions sun at zénith : AM1 conditions (unité atmosphere thickness (7,8km) sun at 30 on horizon : AM2 conditions AM 1.5 spectre : spectre through 1,5 atmosphère (h=41,8 ) z ) 7,8 P (N.m-2) pressure, z (km) altitude A ( ) heigth of sun on horizon.

6 Solar spectrums E = hν = h c λ Esc = 1367 W.m-2

7 Figure 4 : solar and blackbody spectrums Stéphan Astier 15/07/2007

8 Figure 5 : différent solar spectrums with low polluted atmosphères Stéphan Astier 15/07/2007

9 Figure 6.a : annual average duration of insolation (Météo France) Stéphan Astier 15/07/2007

10 Figure 6.c : énergie solaire annuelle moyenne reçue sur un plan horizontal en Europe (Source : EC-IES-pvgis) Energie annuelle moyenne kwh/m 2 /an

11 Figure 6.d : énergie solaire journalière moyenne reçue sur un plan horizontal en Afrique et Méditerrannée (Source : EC-IES-pvgis) Energie journalière moyenne Wh/m 2 /jour

12 Energie solaire annuelle moyenne reçue sur un plan horizontal en kwh 1m kwh par an, 120m 2 12 MWh = 1tep 5000 km 2 0, GWh = Elec France = 0,5 S couvertes km GWh = Elec World km GWh = Energy World S Terre = 510 M km 2, S terres émergées = 149 M km2 (29,3%) 1%

13 In solar photovoltaics AIE : roofs and faces in industrialised country : 20 à 60 % of the electricity : USA 58%, Australie 48%, Canada 35%, Espagne 48%, Italie 45%, Allemagne 30%, France: no evaluation (indeed 40%)! EPIA : available surface disponible in Europe for intégration to buildings 3630 km2 ie 10 m2 by inhabitant, annual 1122 kwh/m2. Europe : 10 m2 of PV captors for each birthday would cover the electricity need for 20 years : symbolic and efficient!

14 Figure 6.e : solar sunpath diagrams in solar hours (cylindrical projection). Site at 43 de latitude Nord et 6 de longitude Est Hauteur α h du soleil Est Azimut solaire α a Ouest

15 Thermodynamic Solar Plants THERMIc storage : several hours Materials : water, oil, melted salts

16 Photovoltaic Solar Systems Stéphan Astier 15/07/2007

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19 Remote solar applications already installed Sites isolés

20 Cumulated Peak Power Remote Applications Grid connected Figure 2 : installed peak power in the world between 1992 and 2004

21 Solar programs Stéphan Astier 15/07/2007

22 Figure 3 : produced and installed peak power by region (Source Solarbuzz et PV News 2006)

23 Sanyo Solar Ark Installation et production photovoltaïque Puissance photovoltaïque crête installée cumulée et répartition par pays. (Source Solarbuzz, PV News) Productions de modules PV

24 Photovoltaique Pointes réseau Base réseau Figure 43 : estimated evolutions of photovoltaïcs Source EPIA Greenpeace Stéphan Astier 15/07/2007 Connecté réseau Industriel isolé Rural isolé Petites applications Emplois en production Emplois en installation Emplois en maintenance

25 Figure 5 : différent solar spectrums with low polluted atmospheres Stéphan Astier 15/07/2007

26 Figure 7 : different photons fluxes for spectrum given on figure 5 Stéphan Astier 15/07/2007

27 Figure 8.a : principle of the photon électron conversion in a system with two levels of energy Stéphan Astier 15/07/2007

28 Power Exceeding energy E>Eg lost in heat Number of photons Energy converted in électricity Photons E<Eg non absorbed 4,0 2,0 Eg 1,0 0,8 E ev λ c 0,5 1,0 1,5 2,0 λμm Figure 8.b : illustration of the double filtering of the solar spectrum in a two level of energy system of photovoltaic conversion, with an Eg Gap fixing the λc cutting wavelenth

29 Figure 9 : theoretical efficiency of an ideal photovoltaic cell under solar spectrum Stéphan Astier 15/07/2007

30 Source : Gozerberg et Hebling 2000, haug et Zurich 2003 Source : Loferski 1956 Figure 10 : theoretical maximal efficiency of photovoltaïc materials

31 Figure 11 : energy levels near the PN junction Stéphan Astier 15/07/2007

32 Figure 8.a : principle of the photon électron conversion in a system with two energy levels

33 Current Voltage Figure 12 : electric characteristics of a PN junction in darkness and under irradiation (E) in motor convention

34 Current I (A/m 2 ) Models of PV cell Points de puissance maximale Iph = Icc Id Ip Vp I P ev = I I exp P CC S 1 KT Ip Rs Iph = Icc Id Rsh Vp Voltage I P = I CC I d R V p SH I d V = Is exp 1 ηvt V T = kt e V(V) With temperature increasing : - Icc increases : di/dt=0,04%/k - Vco decreases : dvco/dt= -0,4%/K - Efficiency decreases : dη/dt= -0,4%/K.

35 Reflected Photons Transmitted Photons hν E g Excess energy of photon hν E g Solar ray Energy Photovoltaic conversion Useful Électricity Recombination Leakage Currents Conduction losses Figure 15 : différent losses attached to PV conversion

36 Current Ip, Pp Ip(Vp) Pp(Ip) = Vp Ip Icc1 Icc2 E1 = 1000 W/m2, T1 < T2 E = 800 W/m2, T2 Vp Ip = Cte Figure 16.a : electric characteristics and power curves for different irradiation and temperature conditions Vco Vp Voltage

37 Current Ip Pp(Ip) = Vp Ip Vp(Ip) Pc = Vc Ic Pm = Vco Icc Icc Ic E = 1000 W/m2 Peak power working point Vc Vco Vp Voltage Figure 16.b : électric characteristic and peak power point of a PV cell at T = 298 K, under AM 1.5 irradiation

38 Source : Gozerberg et Hebling 2000, haug et Zurich 2003 Source : Loferski 1956 Figure 10 : theoretical maximal efficiency of photovoltaïc materials

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40 Figure 17.a : technological constitution of a PN junction PV cell and photography of a great cell 155 mm x 155 mm Figure 17.b : 10x10 cm 2 Si monocristallines celles with special sandwich encapsulation enabling curving without damage so as to fix on curved surfaces. Figure 17.c : multijonctions cell structure. Source : JoachimLuther, Fraunhofer Institute for solar energy systems

41 Axes de recherche : vers une baisse des coûts Amorphous silicon : efficiency improvement, low cost technologies Lower efficiency (10%) but better quality / cost ratio Thin films on glass (1/1000 mm) Organic thin films

42 Current One cell Global Voltage Figure 18 : serie association of ns identical cells

43 Current Voltage Cellule Cf iphf Cellule CF IphF iph R IphF-iphf Figure 19 : serie association of two different cells

44 Current Voltage Figure 20 : PV modules with bypass diodes for protection

45 Current Voltage Figure 21 : parallel association of np identical cells

46 Figure 22 : wiring of a PV panel made of six modules connected in serie (x3) and parallel (x2) with bypass diodes. Photographies on the site of ENS Cachan, antenne de Bretagne à Kerr Lann.

47 Current Power Identical cells Power One module characteristic With weak cells isolated by bypass diodes Voltage Figure 23 : electric characteristics of a generator constituted with np cells in parallel and ns cells in serie

48 Figure 24 : generator with dust on installed in sahelian country Stéphan Astier 15/07/2007

49 Current Optimal zone Stéphan Astier 15/07/2007 Optimal point (Vopt, Iopt) for E=600 W/m 2 Voltage Figure 25 : electric characteristics of a PV panel for different irradiations E : 200 to 1000 W/m 2

50 PV panel Ip Is Vp Static converter adaptator Vs Electric load (consumers) State Tracking control Figure 26 : principle of MPPT (Maximum Power Point Tracking) Real time impédance adaptation

51 I (A/m 2 ) Points de puissance maximale V(V) PV panel Ip Is Vp Static converter adaptator Vs Electric load (consumers) With temperature increasing : - Icc increases : di/dt=0,04%/k - Vco decreases : dvco/dt= -0,4%/K - Efficiency decreases : dη/dt= -0,4%/K. State Tracking control Figure 26 : principle of MPPT (Maximum Power Point Tracking) Real time impédance adaptation

52 Current Identical cells One module characteristic With weak cells isolated by bypass diodes Voltage From the cell to the panel

53 4 3.5 I [A] Panel model as a macrocell Modèle Bond Graph Modèle deux diodes Expérimentation U[V]

54 From the panel to the generator DC bus with battery V Figure 27 : PV generateur of figure 22 constituted of two strings connected to a battery by means of two MPPT systems

55 Figure 29.b : exemple de caractéristiques électriques obtenues en sortie de l émulateur photovoltaïque Figure 29.a : principle of a photovoltaïc emulator Using a buck chopper and a numeric memory

56 Photovoltaic Générateur Grid connexion Raccordement au réseau électrique Generator Photovoltaïque = Inverter Onduleur Batterie Battery (optionnel) (optionnal) Consommation locale Consumers (optionnel) Figure 30 : architectures of grid connected installations

57 Working with storage Working with sun Optimal load Figure 31 : architectures of remote photovoltaïc installations autonomous, isolated of mains

58 Isopower curve Optimal point of generator Optimal load characteristic Optimal point of load Optimal electromecanic characteristic Figure 32 : MPPT strategy optimising both PV conversion and load working.

59 η = 0,7 η = 0,5 Figure 33.a : hydraulic characteristics and iso-efficiency curves of a centrifugal pump with similitude working

60 Solar Energy Figure 33.b : pumping chain PVG Inverter Q Water Pump Water

61 I (A) Electric Energy (Solar, ) Flux vector Electrolyser 0,5 1 1,5 2 V (volt) Hydrogen for energy Stock vector Fuel cell I (A) Figure 41 : reversible electricity to hydrogne transformation

62 4 Icc I (A) Electrolyse cell MPPT with buck chopper 1 PV cell 4 ou 5 PV cells V (volt) 0,5 1 1,5 2 2,5 3 Figure 42 : électric charactéristics of electrolyse cell and PV cell association for direct connection with buck chopper and MPPT

63 Thermo photovoltaïc conversion Stéphan Astier 15/07/2007

64 PHOTOVOLTAÏC GENERATORS PROPERTIES Direct conversion from light to electricity Solar energy exploitation Efficiency 5 à 20% No fluid No moving pieces, static No direct pollution : no emmissions of gaz or noise Lifetime over 20 years High cost Autonomous systems on remote spots Service continuity : storage Design : complex system approach

65 Applications des systèmes photovoltaïques isolés sans stockage

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