Economics of Residential PV Battery Systems in the
Self-Consumption Age
Johannes Weniger, Joseph Bergner, Tjarko Tjaden, Volker Quaschning
HTW Berlin - University of Applied Sciences, Germany
29th European PV Solar Energy Conference and Exhibition
25th September 2014, Amsterdam, The Netherlands
The project “PVprog” (11410 UEP II/2) is funded by the
Environmental Relief Program (UEP II) that is co-financed
by the European Union through the European Regional
Development Fund (ERDF) and the state of Berlin.
Transition from the feed-in into the self-consumption age
Evolution of the cost situation in Germany
0.5
Feed-in
age
Transition
period
Self-consumption
age
€/kWh
0.4
0.3
0.2
0.1
0
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
2
Data: Destatis, BSW, BNetzA (feed-in tariff for PV systems below 10 kWp), HTW
Transition from the feed-in into the self-consumption age
Evolution of the cost situation in Germany
0.5
Feed-in
age
Transition
period
Self-consumption
age
€/kWh
0.4
0.3
0.2
0.1
0
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
3
Data: Destatis, BSW, BNetzA (feed-in tariff for PV systems below 10 kWp), HTW
Required self-consumption rate to preserve profitability
Required self-consumption rate
0.20
60%
55%
PV electricity cost in €/kWh
0.18
50%
50%
45%
40%
0.16
40%
30%
0.14
35%
20%
0.12
30%
10%
25%
0%
20%
0.10
15%
10%
0.08
5%
0.06
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Feed-in tariff in €/kWh
4
Applicable for PV systems below 10 kWp assuming a mean retail price of 0.34 €/kWh
0%
Energy flows of homes equipped with PV battery systems
PV system
Battery
system
Loads
Direct use
Battery charge
Battery discharge
Grid feed-in
Grid supply
Grid
5
Cash flows of homes equipped with PV battery systems
PV system
Battery system
Expenses
• Investment cost
• Operational cost
• Cost of financing
• Investment cost
• Operational cost
• Cost of financing
for the grid supply
+
Mean electricity cost
€/kWh
6
from the grid feed-in
l
+
Revenues
Assumptions of the economic assessment
Rated PV power related to annual load demand
1 kWp/MWh
Usable battery capacity related to annual load demand
1 kWh/MWh
Feed-in tariff
0.12 €/kWh
Mean retail electricity price
0.34 €/kWh
Period of time
20 years
Annual operational cost
1.5%
7
%
Interest rate
4%
Mean electricity cost for varying system prices
2250
Mean electricity cost in €/kWh
0.50
0.48
0.46
0.44
1750
0.42
0.40
1500
0.38
0.36
1250
0.34
0.32
1000
0.30
0.28
750
0.26
0.24
500
0.22
250
1000
1200
1400
1600
PV system price in €/kWp
8
1800
2000
0.20
Limit of profitability
Battery system price in €/kWh
2000
Mean electricity cost for varying system prices
2250
Mean electricity cost in €/kWh
0.50
0.48
0.46
1750
0.42
0.40
1500
0.38
0.36
1250
0.34
1160
0.32
1000
0.30
0.28
750
0.26
0.24
500
0.22
250
1000
1200
1400
1600
PV system price in €/kWp
9
1800
2000
0.20
Reference case
0.44
Limit of profitability
Battery system price in €/kWh
2000
Sensitivity analysis of the required battery system price
Required battery system price in €/kWh
2250
Reference case
0%
2000
1750
1000 €/kWp
1500
1250
1160
0.38 €/kWh
1500 €/kWp
0.12 €/kWh
0.34 €/kWh
1000
0.30 €/kWh
750
0.04 €/kWh
2000 €/kWp
500
8%
%
250
PV system price
10
4%
Feed-in tariff
Retail price
Interest rate
Sensitivity analysis of the required battery system price
Required battery system price in €/kWh
2250
Reference case
0%
2000
1750
1000 €/kWp
1500
1250
0.38 €/kWh
1500 €/kWp
0.12 €/kWh
0.34 €/kWh
1000
0.30 €/kWh
750
0.04 €/kWh
2000 €/kWp
500
8%
%
250
PV system price
11
4%
Feed-in tariff
Retail price
Interest rate
Conclusion
12
•
Self-consumption of PV energy is becoming an essential
prerequisite for the profitable operation of PV systems.
•
The profitability of PV battery systems is subjected to a
variety of input parameters.
•
The major factor is the interest rate, followed by the PV
system price, retail electricity price and feed-in tariff.
•
Required battery system prices in the range of about
500─2000 €/kWh have been determined.
•
Investing in a PV battery system will become more
attractive than purchasing the entire electricity demand
from the grid.
•
It can be expected that most of the residential PV
systems will be equipped with batteries in the future.
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