The document discusses the design and analysis of a photovoltaic (PV) system installed on a house in Northern Italy. It describes the site details and energy usage, the 2.94 kW PV system components and specifications, tests and inspections conducted, a bill of materials, and an investment analysis. The investment analysis found a 5.4% rate of return over 20 years based on incentives of 0.49 Euros/kWh for the PV-generated energy and estimated energy savings of around 3000 kWh per year.

1. Webinar - 9 May 2008 Case Study - Photovoltaics

2. Index Site Design criteria PV system components Tests and inspections Bill of materials Investment analysis Summary

3. Site > Where

4. Site > Global horizontal irradiation (kWh/m 2 year) Source: PVGIS © European Communities, 2001-2007 http://re.jrc.ec.europa.eu/pvgis/ 1300 kWh/m2 per year

5. Site > Electricity from PV systems Source: PVGIS © European Communities, 2001-2007 http://re.jrc.ec.europa.eu/pvgis/ (1100 kWh/kWp year)

6. Site > The house

7. Site > The house Area: 356 m 2 Electricity consumption: 5.500 kWh/year

8. Site > The house Orientation Roof area (South): 95 m 2

9. Site > Area for installation Orientation: South Area: 45 m 2 Slope: 19°

10. Design criteria Available surface Feed-in tariff maximization 2005 – Ministerial Decree referred to in Art. 7, para. 1 of Legislative Decree no. 387 of 29 Dec. 2003. Criteria for incentivising electricity generation by photovoltaic solar plants 2005 - AEEG - electricity & gas regulator adopted its Decision 188/05, which identifies GRTN (now GSE) as “implementing body” in charge of granting incentivising tariffs 2006 - second decree on photovoltaic solar generation, extending and supplementing the Ministerial Decree of 2005, was enacted Incentive scheme applies to photovoltaic (PV) solar plants or systems which have a capacity of 1 to 1,000 kW and which have become operational after 30 Sept. 2005

11. Design criteria > Incentivising tariffs 0,44 0,4 0,36 P > 20 kW 0,46 0,42 0,38 3 kW < P ≤ 20 kW 0,49 0,44 0,4 1 kW ≤ P ≤ 3 kW Integrated Partially integrated Not integrated Incentivising Tariffs (€/kWh) PV System Capacity (kWp)

12. Design criteria > Contract Type and Energy usage PV energy Contract Type No sale Partial sale Complete sale Net Metering Energy sale

13. Design criteria > Contract Type and Rated Power PV system Net metering ≤ 20kW Sale contract > 20kW

14. Design criteria > Contract Type and PV energy value PV energy Used Net metering Used Sale contract To grid To grid Energy Energy 0,4 €/kWh 0,12-0,18 €/kWh 0 €/kWh 0,12-0,18 €/kWh 0,1 €/kWh

15. Design criteria > PV System size 2,94 kWp

16. PV system components (PV SC) PV Generator Inverter DC & AC Cables AC & DC disconnecting switch AC & DC overcurrent protection Metering Earthing Overvoltage protection Grid connection

17. PV SC > System overview Grid Energy measurement Coupling point Main Switch Load Interface Int. Protection PV energy measurement PV System switch Inverter PV modules

18. PV SC > PV Generator, module features

19. PV SC > PV Generator, module features

20. PV SC > PV Generator Module Diode 407,40 Vmpp @ STC (V) 344,73 Vmpp, min @ Ta, max (V) 460,74 Vmpp, max @ Ta, min (V) 9,91 Isc, max (A) 562,94 Voc, max @ Ta, min (V) 2940 System rated peak power (W) 1 Arrays 14 Modules

21. PV SC > PV Generator > constructive aspects PV module Roof underlay Tiles Orientation : -5° (South 0, East -90, West 90) Slope : 19°

22. PV SC > PV Generator > Final result

23. PV SC > Inverter, MPPT I V PV generator Inverter T cell, min T cell, max MPP MPP

24. PV SC > Inverter, efficiency Inverter n. 1 Inverter n. 2 MPPT adjustment efficiency Source: Photon International www.photon-magazine.com

25. PV SC > Inverter, efficiency Inverter n. 1 Inverter n. 2 Overall efficiency Source: Photon International www.photon-magazine.com

26. PV SC > Inverter

27. PV SC > DC & AC Cables Uo/U Section Capacity Voltage drop Cross section: 4, 6 mm 2 Formation: 1X 0,6/1 kV

28. PV SC > DC & AC Cables Type External installation Anti-Fraud

29. PV SC > AC & DC disconnecting switch & overcurrent protection Inverter PV modules Meter QS 2 QP1 To load Grid Existing electrical installation QS 1

30. PV SC > AC & DC disconnecting switch & overcurrent protection Inverter PV modules Meter QS 2 QP1 To load Grid Existing electrical installation QS 1

31. PV SC > AC & DC disconnecting switch & overcurrent protection 0,3 Rated residual current B Residual current type 6 Breaking capacity C Curve Magnetic release type C Curve Termical release type 25 32 16 Rated current QS 1 QS2 QP1

32. PV SC > Metering PV system energy Produced To grid From grid Measurement system Installation and maintenance Recording Transmission Location Type of connection Direct Indirect Semi-direct On way meter Two way meter Near the inverter

33. PV SC > Earthing All exposed conductive parts and the whole electrical system A PV system can be connected to earth only if a transformer separates it from the grid Without separation, PV system is considered as part of the grid, which already has an earthing connection. PV system is then connected to earth through the grid.

34. PV SC > Overvoltage protection Direct lightning strike Building LPS ? PV system increases strike frequency? Class 1 LPS New risk assessment LPS integration Risk assessment No No No Yes Yes Yes

35. PV SC > Overvoltage protection Indirect lightning strike SPD SPD SPD PV System

36. Tests and Inspections On site (acceptance and periodic) inspections Shadows Equipment Tests DC side AC side At acceptance: Array voltage and current Circuit insulation Equipotential bonding

37. Tests and Inspections > On site inspections Inverter Rack Cables Modules Yes Yes Plate damage Yes Yes Fan Yes Yes Connections Yes Yes Operation and alarm signalling No Yes Inverter proper installation Yes Yes Plate damage Yes Yes Earthing conductors damage Yes No Fuses Yes No Water/corrosion Yes Yes Terminal installation No Yes Rack proper installation Yes Yes Circuit identification Yes No Mechanical and fault stresses No Yes Cables type and installation Yes Yes Plate damage Yes No Boxes damage Yes Yes Earthing conductors damage Yes No Frame corrosion Yes Yes Module damage Yes Yes Module installation Periodic inspection Acceptance Type

38. Bill of materials Modules: 14.200€ Inverter: 1.900€ Other (cables, accessories, etc…): 7.081€ Total: 23.181€ Specific cost: 7.884 €/kW

39. Investment analysis > Energy cost Environment and energy. 2006. (epp.eurostat.ec.europa.eu) Calculation made on the basis of variation average index for domestic energy cost calculated for 2000-2006 (source Eurostat) Average: +0,26% / year 0,29 20 0,19 1 Electric energy (€/kWh) (VAT excluded) Year

40. Investment analysis > Cash Flows 5,4% Rate of return +7684,4€ NPV 2% Discount rate € 14.543,93 -€ 1.220,01 -€ 21.080,36 -€ 23.181,31 Cash flows € 1.931,33 -€ 764,79 € 2.100,96 Balance -€ 100,00 -€ 2.881,76 -€ 100,00 -€ 23.181,31 Total € - € - € - Insurance € - -€ 2.781,76 € - Maintenance -€ 100,00 -€ 100,00 -€ 100,00 Operative Costs € 2.031,33 € 2.116,97 € 2.200,96 Total € 1.234,57 € 1.356,50 € 1.524,15 Incentives € 796,77 € 760,47 € 676,80 Energy savings € - € - € - Energy sale Incomes 20th 12th 1st 0 Year

41. Investment analysis > Cash Flows

42. Summary Site location: Northern Italy Irradiation: 1058 kWh/kWp System power capacity: 2,94 kW System installation: roof integrated Investment cost: approx. 23.000€ Specific cost: 7.884 €/kW Incentive: 0,49€/kWh Investment rate of return: 5,4% Energy savings: ~ 3000 kWh/year Emissions savings: 2350 kg CO 2 /year