IEEE Power & Energy Magazine - Grid Edge 2023 - 30

10
9
8
7
6
5
4
3
2
1
45
40
35
30
25
20
15
10
5
GWp
Share of PV Systems
on German Electricity
Consumption
8
7
6
5
4
3
2
1
figure 1. Annually installed PV capacity in Germany as of
July 2014 (source: www.energymap.info).
The batteries are designed to cope with PV systems whose
nominal power is 5-8 kWp, and their capacities usually vary
from 2 kWh to 12 kWh. The prices for such battery systems
still vary considerably and depend greatly on the technology
used and the capacity of each system. Most suppliers, however,
currently offer their PV storage systems for €5,000-
15,000; such systems typically include a 5-kVA inverter and
a 4-kWh lithium-ion battery.
In May 2013, the German government introduced an
incentive program that financially supports investments in
residential-scale PV storage systems. In addition to a soft
loan, the program provides up to €600 per installed nominal
kW of PV capacity when a battery system is installed
in parallel. The program obligates participants to limit the
active power feed-in over the household's point of common
40
35
30
25
20
15
10
5
figure 2. Accumulated installed PV capacity in Germany
and the share of PV energy in total German electricity consumption,
as of July 2014 (source: numbers for the installed
capacity from www.energymap.info and German net electricity
consumption from https://www.bdew.de/internet.nsf/
id/DE_Energiedaten).
coupling to 60% of the installed PV capacity. So far, approximately
15,000 PV storage systems have been sold since the
beginning of the investment program.
To assess the economic viability of the PV storage
option, a short case study will be presented. Accordingly,
various household consumption profiles, PV system sizes,
and battery sizes are simulated to determine the resulting
self- consumption, self- sufficiency, and grid feed-in numbers.
Figure 5 displays self-consumption and self-sufficiency for
different PV battery configurations for a sample household-
in this case, a four-person family.
Self-consumption and self-suffi37.47
32.005
27.239
24.911
21.238
12.068
9.24
5.997
7.14
4.082
3.873
Data Source: German Federal Network Agency for Electricity, Gas,
Telecommunications, Post, and Railway, " Monitoring Report 2013 "
figure 3. Installed capacities of different electricity sources in Germany as of 2013.
30
ieee power & energy magazine
ciency show the PV battery system's
capability to reduce grid feed-in of
generation and to reduce grid supply
for local load demand. A PV selfconsumption
of 100% indicates that
all of the locally produced PV energy
is consumed locally, and a self-sufficiency
of 100% indicates that no
electricity from the grid is consumed.
The trade-off between self-consumption
and self-sufficiency thus
becomes visible. Smaller sizing of
PV systems allows for increased selfconsumption
but lowers the potential
for increased self-sufficiency.
Further analyses show how
optimal installed system sizes
change with a decreasing FIT and
an increasing electricity price. In
the future, though, local generation
via PV systems will need to be
more finely adjusted to local load
march/april 2015
Installed Capacity (GW)
Annually
Installed PV Capacity (GWp)
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
Installed PV Capacity (GWp)
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
Share of PV Energy on German
Electricity Consumption (%)
Photovoltaic
Wind Onshore
Natural Gas
Hard Coal
Brown Coal
Nuclear
Pump Storage
Biomass
Mineral Oil
Hydro
Misc.
http://www.energymap.info http://www.energymap.info https://www.bdew.de/internet.nsf/id/DE_Energiedaten https://www.bdew.de/internet.nsf/id/DE_Energiedaten
IEEE Power & Energy Magazine - Grid Edge 2023

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