Renewables for Self-Supply - German and international experiences" Prof. Dr. Stefan Krauter 6 th of September 2016 Windhoek, Namibia

Renewables for Self-Supply - German and international experiences" Prof. Dr. Stefan Krauter 6 th of September 2016 Windhoek, Namibia

Potential for different energy carriers Prof. Stefan Krauter Namibia, 6/9/2016 Page 2

First applications of PV (PV 1.0) Space, science fiction & remote energy supply 1960-2000 Important: Far away from electrical grid Prof. Stefan Krauter Namibia, 6/9/2016 Page 3

Scheme of a simple Solar-Home-System (SHS) Prof. Stefan Krauter Namibia, 6/9/2016 Page 4

Examples: Charge controllers & Inverters for off-grid systems Prof. Stefan Krauter Namibia, 6/9/2016 Page 5

Traditional markets for Off-grid PV systems Prof. Stefan Krauter Namibia, 6/9/2016 Page 6

New (2015) cost share of an autonomous PV system for 20 years (20 kw p, 60 kwh supply per day) Prof. Stefan Krauter Namibia, 6/9/2016 Page 7

PV 2.0 Grid-connected PV systems (PV grid injection): 2000-2015 Junction box PV generator Local loads Grid connection kwh-meter: Consumption vs PV energy Inverter (grid synch.) Important: Effective Feed-In Legislation Prof. Stefan Krauter Namibia, 6/9/2016 Page 8

Grid-connected residential PV systems (Freiburg/Germany) Prof. Stefan Krauter Namibia, 6/9/2016 Page 9

Price development & BoS-share Rooftop PV systems in Germany Average end customer price (net system price) for installed rooftop systems with rated nominal power from 10-100 kw p (small systems); data from BSW, plotted by PSE AG. Prof. Stefan Krauter Namibia, 6/9/2016 Page 10

Solar modules may also serve as shading elements: Saves energy for air-conditioning! Prof. Stefan Krauter Namibia, 6/9/2016 Page 11

Grid-connected 11 MW PV system (Cerpa/Portugal) Prof. Stefan Krauter Namibia, 6/9/2016 Page 12

Potential for different energy carriers Solar irradiance in Africa Prof. Stefan Krauter Namibia, 6/9/2016 Page 13

Solar irradiance and PV generation in Namibia Yearly sum of global irradiation in kwh/m² Electricity consumption of Namibia: 4 TWh/a PV area: 20 km² 4.5 x 4.5 km Yearly sum of electricity generation of a 1 kw p PV system (performance ratio: 0.75) in kwh/kw p Prof. Stefan Krauter Namibia, 6/9/2016 Page 14

Development of PV electricity costs in Germany (900 PV full-load hours per year) & in S-countries (1800 PV full-load hours per year) Since 2012: PV electricity cheaper than consumer tariff Cost reduction values have been achieved 8 years ahead of scheduled time Costs for electricity supply (grid & PV) References: Hoffmann 2000, Krauter 2014 PV Peak load Base load 900 h/a 0.10 /kwh 1800 h/a 0.06 /kwh Prof. Stefan Krauter Namibia, 6/9/2016 Page 15

Cost comparison of Diesel generation vs. PV Irradiance in most of Namibia Good value in Germany Namibia Source: C. Breyer, RLI, 5th ARE Workshop Academia meets Industry, 27 th EUPVSEC, Frankfurt 2012 Prof. Stefan Krauter Namibia, 6/9/2016 Page 16

Long-term cost development of fossil fuels Cost Increase: ca. 100% per decade Prof. Stefan Krauter Namibia, 6/9/2016 Page 17

Scheme of direct use, grid-feeding, storage for self-supply Option: small wind power plant Reference: Weniger et al. EUPVSEC 2014 Prof. Stefan Krauter Namibia, 6/9/2016 Page 18

Wind power use: More cost efficient = larger systems Prof. Stefan Krauter Namibia, 6/9/2016 Page 19

Wind power use: Trend to larger systems: More cost efficient & higher specific yield & higher capacity factor For residential applications, wind power is generally not a viable option: Small Wind power converters are relatively expensive Lifetime is often quite short (no general quality test such as IEC 61215 for photovoltaic generators) Capacity factor and yield is low due to low installation height Predictability in most locations (such as Namibia) is more difficult Therefore, this presentation is focused on Photovoltaics Prof. Stefan Krauter Namibia, 6/9/2016 Page 20

Seasonal challenge: Demand and generation from wind & solar during a year Problem in Germany, but not in Namibia Monthly distribution (annual total = 100 percent) of solar power calculated for Freiburg [PVGIS], wind power [DEWI], heating requirements based on the heating degree days (VDI Guideline 2067 and DIN 4713), energy requirements for domestic hot water production, electricity demand [AGEB1] and fuel requirements [MWV]. Estimate. Source: ISE 2016 Prof. Stefan Krauter Namibia, 6/9/2016 Page 21

Daily challenge: Excess PV during midday hours: PV electricity sold to gridoperator during midday, bought back during nighttime: Good with net-metering Reference: GTAI 2015 Prof. Stefan Krauter Namibia, 6/9/2016 Page 22

PV electricity stored in battery during midday period, used during nighttime Reference: GTAI 2015 Prof. Stefan Krauter Namibia, 6/9/2016 Page 23

Options for Storage Technologies as a function of storage capacity and duration of storage Comparison of Storage Technologies, Source: Breyer Prof. Stefan Krauter Namibia, 6/9/2016 Page 24

PV with storage reduces electricity from grid by 60% in Germany; in Namibia 100% are possible! Prof. Stefan Krauter Namibia, 6/9/2016 Page 25

Prof. Stefan Krauter Namibia, 6/9/2016 Page 26

Hint: Conventional charging regime does not reduce midday-peak production: No relief for the grid by PV! Prof. Stefan Krauter Namibia, 6/9/2016 Page 27

Hint: Adapted charging: Relief for the grid by PV! Prof. Stefan Krauter Namibia, 6/9/2016 Page 28

Economics of self-supply - background: Electricity costs and feed-in tariffs for wind & solar in Germany Prof. Stefan Krauter Namibia, 6/9/2016 Page 29

Price development for electricity from grid, PV, PV + battery storage (in Germany; for residential applications) Cost benefit for self-supply: Break-even reached For Namibia, PV electricity costs about 0.05 /kwh PV + Battery: 0.25 /kwh (higher degradation of battery) Prof. Stefan Krauter Namibia, 6/9/2016 Page 30

Battery storage costs are presently at 0.2 /kwh (four times the costs of PV electricity in Namibia) what is the development? Prof. Stefan Krauter Namibia, 6/9/2016 Page 31

Instead of waiting until battery prices will fall: Demand-side-management Demand side management with PV: 1. Increase consumption during midday hours (washing, pressing, dishwashing, heat & cooling applications) 2. Use thermal storage instead of expensive electrical storage: Freezers with good insulation & high thermal capacity Hot water storage Adapt industrial processes 3. Orient PV slightly more towards West: More power in the evening Prof. Stefan Krauter Namibia, 6/9/2016 Page 32

Thank you! Questions? Prof. Dr. Stefan Krauter Stefan.Krauter@upb.de

Cost development of LiO electricity storage capacity by different literature sources (Reference: Nature Climate Change) Prof. Stefan Krauter Namibia, 6/9/2016 Page 34