Technology and Economics of PV Systems in Germany Regarding the probably coming new EEG revision April 2012

Transcription

1 Energy Technology and Economics of PV Systems in Germany Regarding the probably coming new EEG revision April 2012 Michael Vogtmann DGS e.v. International Solar Energy Society / German Section, Chairman of the Frankonian Section Riad, 13 May

2 Basics - Energiesource Sun Sun irradiation: Germany kwh /(m 2 a) to kwh/(m 2 a): up to kwh/(m 2 a) in Saudi-Arabia:(aequivalent 200 l oil)

3 Basics Sunlight turns into electricity Solarmodules convert the energy in the sun light (radiation energy in kwh) directly into electrical energy (Direct Current DC in kwh).

4 Basics Sunlight turns into electricity Solarmodules convert the energy in the sun light (radiation energy in kwh) directly into electrical energy (Direct Current DC in kwh). Sun resistant cables carry the Solar(direct)current to the inverter, which transforms it into low voltage current: 230 Volt alternating current (AC)

5 Basics Sunlight turns into electricity Solarmodules convert the energy in the sun light (radiation energy in kwh) directly into electrical energy (Direct Current DC in kwh). Sun resistant cables carry the Solar(direct)current to the inverter, which transforms it into low voltage current: 230 Volt alternating current (AC) The generated electrical work of the (AC)current is measured in kilowatt hours (kwh) due to a electricity meter.

6 Basics Sunlight turns into electricity Solarmodules convert the energy in the sun light (radiation energy in kwh) directly into electrical energy (Direct Current DC in kwh). Sun resistant cables carry the Solar(direct)current to the inverter, which transforms it into low voltage current: 230 Volt alternating current (AC) The generated electrical work of the (AC)current is measured in kilowatt hours (kwh) due to a electricity meter. The electrical work feeds into own grid oder public grid. according to technical performance, local irradiation and purchase cost this leads to a specific kwh-price. Purchase costs refer to kwp.

7 Basics Sunlight turns into electricity The electricity is paid at a rate guaranteed by law. If the solar power is fed 100% into the grid, the remain purchase of power and associated costs are not affected by feeding. In the public grid the electricity is used by other consumers and thus can replace conventionally generated electricity.

8 Basics Sunlight turns into electricity Own use of electricity: Whenever it is possible and useful, the solar electricity is self used. Excess electricity is fed into the public grid. The own purchase of public electricity is reduced. These avoided costs affect the economics of the PV system. In Germany often beneficial, since purchase costs of electricity are mostly higher than the feed-in rate.

9 Basics Space Reqirements Cristalline technology: 6 to 10 m 2 per kwp Thin layer technology: 9 to 16 m 2 pro kwp kwp under STC: 1000 W/m 2 Cell-Temperature 25 C AM (AirMass) = 1,5

10 Basics Angles, solar altidude, modul altitude Source: PVscout Best: Solarmoduls due south in northern hemisphere (same in Saudi-Arabia). But: Between east and west is also good. Source: SMA Best modul altitude in Germany: 30 But: Between 0 (flat) and 50 also good Saudi-Arabia: Best, 0-30 all good Result: Nearly all typical roofslopes between south east and south west provide more than 90% irradiation compared with due south, 30.

11 PV Systems - Overview Photovoltaic Systems Grid Connected Systems Stand-alone systems 100% fed into grid First own consumption, only excess electricity fed into grid with storage Hybridystems systems without AC - circuit with windpower with CHP Systems with AC - circuit with dieselgenerator

12 Stand Alone Systems Rural areas and sea water desalination DC Systems: with accumulator and charge controler DC/AC Systems: with accumulator, charge controler and stand-alone inverter 8 kwp PV stand alone system for seawater desalination in Jeddah (Saudi-Arabia) from 1982.

13 Components - Overview Which components belong to a gridconnected PV System? Inhouse Power grid Public Power grid Feed-in - point Electricity meter Solar generator = ~ Control-function Inverter

14 Components Solar Cell Cell Types cristalline silicon thin layer cells polycristalline silicon monocristalline silicon amorphous silicon (a-si) Copper-Indium- Diselenid/Sulfid (CIS) Cadmium-Tellurid (CdTe)

15 Components Solar Cell The photovoltaic effect (example: cristalline silicon) negative electrode - n-doped silicon (Phosphor) positive electrode + boundary layer No wear, no rotating parts, no fumes, no noise. No other type of power generation has these advantages at the same time. p-doped silicon (Bor)

16 Components - Cell, semiconductor cristalline silicon mono- und polycristalline silicon-cell Production with high energy input (at 1500 degrees Celsius) cell-efficiency: appr. 15% to 20% (Moduls 13% to 18%) Space requirement: 6 to 10 m 2 per kwp Long term experience over decades performance warranty (80%) : 20 till 30 years Appearance monocristalline: darkblue or black polycristalline light-, medium- or darkblue, often inhomogeneous structure Performance with diffuse light less efficient than thin layer technology (S.-A.: not so relevant) More temperature sensitive than thin layer cells (S.-A.: relevant)

17 Components - Cell, cristalline silicon (Mostly) serial connecting of cells: mostly between 48 and 72 Cells per modul Lamination of glass, cells, backside material with plastic film and tedlar (at 150 degrees Celsius) Junction box mit bypass diodes and sun-resistant cables Framing (for mechanical protection) Endcontrol: Solarmodul completed

18 Components - Cell, thin layer cells Deposition of photoactive semiconductors on a substrate (glass, plastic, ) at 200 bis 600 C Thickness of layer less than 0,001 mm Production at a high degree of automation No standard measurements of cells Interconnection of cells immediately during manufacture Quelle: DGS 1

19 Components - Cell, thin layer cells Amorphous Silicon-cell, CIS-cell, CdTe-cell Production cheap - low material use - low energy input Cell-efficiency between 5% (a-si) to 12% (CIS) Space reqirements 9 bis 16 m 2 per kwp higher output tolerances than cristalline Performance with diffuse light more efficient than cristalline technology (S.-A.: not so relevant) Less temperature sensitive than cristalline (S.-A.: relevant)

20 Interconnection of the cell to the whole PV System An example Voltage U in V Current I in A Power P in Wp one cell 0,5 7,7 3,85 one module with 60 cells 30 7, cells in series one String mit 22 Modulen One Inverter with 44 moduls 5 String- Inverters 660 7, moduls in series , Each 660 Each 14, Moduls in series, two Strings parallel PV System: 50,8 kwp

21 Components Mounting Systems Different roof hooks Free standing installations Mounting Modules on horizontal support rails Do not compromise with quality: it s meant for 30 years!

22 Components The Inverter Feature: Often a combination of Series Connection and Parallel Connection High voltage: advantageous for a relatively low cable cross section to avoid high losses of energy String inverters and central inverters Efficiency DC/AC Converting: > 95%

23 Grid Connection Highest voltage grid 220 kv / 380 kv High voltage grid (PV System > 10 MW) 60 / 110 kv Medium voltage grid (PV System > 100 kw) 6 / 10 kv; 20 kv Low voltage grid (PV Systems < 100 kw) 230 / 400 V source: SMA

24 25,0 20,0 15,0 10,0 5,0 Radiation, performance and daily yield Current performance (in kw) of a 24 kwp PV-System Current radiation in W/m ,0 Clear sky, cloudless high radiation high yield cloudy changing radiation medium yield Covered, small sun small radiation lower yield 0,0 6,38 kwh/kwp In Saudi-Arabia: almost daily! 3,12 kwh/kwp 1,71 kwh/kwp

25 Space Reqirements for large roofs and expected solar yields Flatroof: approx. double size of modulesize to avoid shading of moduls eath other. horizontally full use of roof space (but cleaning then important) west/east with 10 angle Image: Schletter Size: appr. 500 kwp on 1 acre Yield: appr kwh/kwp/a Whole yield: appr. 500 MWh/a Production costs of AC current: appr Ct./kWh Saudi-Arabia: Yield: appr kwh/kwp/a Whole yield: appr MWh/a Production costs of AC current: appr Ct./kWh (?) Images: Sunova

26 Space Reqirements for ground field and expected solar yields Ground field: Approx. double size of modulesize as distance between rows to avoid shading module to module Size: appr. 500 kwp on 1 acre Yield: appr kwh/kwp/a Whole yield: appr. 500 MWh/a Production costs of AC current: appr Ct./kWh Saudi-Arabia: Yield: appr kwh/kwp/a Whole yield: appr MWh/a Production costs: appr. 5-9 Ct/kWh (?) Images: Schletter

27 Economic considerations specific annual yield (kwh/kwp) Economics of PV systems in 2012, represented by return on equity as a percentage % 10% 11% 9% 8% 7% 6% 5% 4% 3% - relevant for systems less than 10 kwp % - Financing with 100% equity capital - Operating costs and in addition to costs regarded % feed-in, rest self used Return on Equity 750 between 3% and 7% net-investment expenses ( /kwp)

28 Chances for PV in Saudi-Arabia Highest irradiation worldwide and relatively uniform each day throughout the year Best chances to produce a maximum for daily domestic power demand. More solar electricity production in Summer months corresponding to more demand because of electrical air conditioning Best chances for production of solar components and export together with competent partners in east and west Images: Schletter

29 A surface of approx. 32 x 32 km (1000 km 2 ) would be enough to produce the whole Electricity power of Saudi-Arabias demand in 2010 (200 Billion kilowatthours) with own Solar electricity. A surface of km 2 would produce todays total annual world energy demand.

30 Thank you very much for your attention!