Results from PV GRID
Research for Germany
PV Curtailment and Prosumer Storage
Bianca Barth,
BSW-Solar
Dr. Oliver Franz,
RWE Deutschland AG
London,
22 Ocotber 2013
1
Outline
• Development of the German PV market
• Effectiveness of technical solutions in Germany
• Limited RES curtailment –
Barrier and possible solutions for Germany
• (Still too) High Costs of Prosumer Storage –
Barrier and possible solutions for Germany
 KfW support program
23/10/2013
2
Development of the German PV Market
MWp
Entwicklung der PV-Installationen
J ährlich neu installierte Leistung in MWp seit 200 0
8.000
Market
data
for PV in
Germany 2012
Marktdaten
Photovoltaik
in Deutschland
2012
7.000
6.000
5.000
Neu installierte PV-Leistung*
Gesamt installierte PV-Leistung*
Newly installed PV capacity*
Solarstromerzeugung**
Overall installed capacity *
Anzahl installierter Anlagen**
7.400
7.500
7.600
2010
2011
2012
7.600 MWp
32.000 MWp
7.600 MWp
28.060 GWh
32000 MWp
1.280.000
Electricity production from PV
Amount of installations**
* gerundete Werte von Januar bis Dezember 2012
vorläufige
Schätzung
* **rounded
values
** preliminary estimate
28.060 GWh
1.280.000
3.800
4.000
3.000
1.940
2.000
1.270
1.000
930
850
2005
2006
660
45
115
113
147
2000
2001
2002
2003
0
2004
2007
2008
2009
Quellen: BSW-Solar, BNetzA, EEX, Stand 01/2013
23/10/2013
3
Most effective technical solutions at LV level
Technical solution
DE
Curtailment of power feed-in at PCC
Network Reinforcement
Reactive power control by PV inverter Q(U) Q(P)
Active power control by PV inverter P(U)
Prosumer storage
On Load Tap Changer for MV/LV transformer
Adoption of solution requires regulatory changes
Can be applied where problems occur
The majority of solutions that were identified as most technically
effective by PV Grid are already available in Germany!
4
Limited RES curtailment –
Barrier and possible solutions for Germany
23/10/2013
5
Limited RES Curtailment as an example of a
barrier and possible solution in Germany
• Problem: Curtailment is only accepted for system security reasons in
emergency situations and if (local) bottlenecks can not be overcome in
the short to medium term and the DSO must overcome the bottleneck
as soon as possible
• Solution / Opportunity: Advanced, but limited curtailment reduces grid
expansion needs and may be used in order to help increasing the grid
hosting capacity
• Challenge / Possible conflict: Curtailment reduces investment security
and puts RES growth at risk (if losses are not fully compensated)
• Discussed recommendation:
DSOs could use curtailment as an alternative option to grid expansion if
the savings for the avoided grid reinforcement are higher than the costs
“caused” by the full reimbursement of curtailment.
23/10/2013
6
Current regulation for curtailment in Germany
• Since January 2012:
 PV systems >30 kWp must be equipped with a means to curtail
power by remote control; compliance required as of grid connection
2009 or later (Retrofit of ~ 50.000 systems)
 PV systems <30 kWp have a choice to either reduce injected active
power to a maximum of 70 % of the installed capacity or to install the
same technical equipment as plants >30 kWp.
• DSO may curtail power in case of local bottleneck / too
much power on the grid




Mainly ripple control receivers are used
Trend towards GSM based remote control systems
Typically 4 steps of power control: 100%, 60%, 30% and 0%
PV plant operator gets compensated for lost energy
23/10/2013
7
Data on RES-Curtailment
Topic is already relevant and will become even more important
moving forward…
2009
2010
2011
RES power production compensated by feed-in
tariff (sold via EEX by the TSOs)
75.034
GWh
80.672
GWh
91.227
GWh
RES power production directly sold via the EEX
by owner of RES systems
----
1.587
GWh
11.650
GWh
75.034
GWh
82.259
GWh
102.877
GWh
 Note: The main power source affected was wind.
74
GWh
127
GWh
421
GWh
Curtailment quota
0,1%
0,16%
0,41%
Overall RES production fed into the grid
RES power production curtailed
Source: BNetzA – Monitoringbericht 2011 & 2012
23/10/2013
8
A permanent but limited form of RES-Curtailment –
Restrictions and Conditions
• RES plant operators need to be able to recognize and comprehend
any interventions in the power supplied by their RES plant.
• Strict cap of maximum curtailment in the local grid as a percentage
of yearly production (not more than a certain percentage figure).
• Every curtailed kilowatt-hour must be fully reimbursed.
• The costs for reimbursement should always be lower than the
avoided costs for grid expansion, proven to the responsible
regulatory agency upon request.
• The adoption of curtailment should be limited to management of
congestion at the local distribution grid. Basically, any specific
curtailment measures have to be “allocated” to a specific congestion
area.
23/10/2013
9
A permanent but limited form of RES-Curtailment
– Restrictions and Conditions (continued)
• The network operator responsible for higher network levels
(affected directly or indirectly) has to base his grid capacity
planning on the non-curtailed kilowatt-hours that would be
injected into the network without any curtailment since
alternative grid enforcement measures might be applied with the
consequence that curtailment will no longer be necessary.
• Immediate start of grid reinforcement measures before either
maximum cap or limit of curtailment are reached or when
curtailment is no longer the most efficient alternative.
• Curtailment should be designed in a way that will not distort any
incentives for (self-) consumption that exist today or will be
developed in the future.
23/10/2013
10
(Still too) High Costs of Prosumer Storage –
Barrier and possible solution for Germany
23/10/2013
11
Small-scale PV storage systems can relieve the grid
• Grid benefits (study of BSW / Fraunhofer):
 Power peaks can be reduced by 40% without power losses by curtailment
 Increase of up to 66% of integration capacity in the local grid
23/10/2013
12
High Costs for Prosumer Storage –
Barrier and possible Solution for Germany:
• With increasing fluctuant power production, the demand for
flexibility options within the power supply system will rise.
 Prosumer storages could help to avoid production peaks
and to increase self-consumption
• Problem:
There is still a financial barrier to be overcome as the
costs for storage systems are (too) high.
• Recommendation:
Support the development of storage technologies
23/10/2013
13
KfW support program for battery storage
systems took effect on May 1st 2013
 Program provides low-interest loans and repayment
subsidies for solar PV installations which incorporate a
fixed battery storage system
 Requirements and technical prerequisites:
 Grid supporting operation of storage system
 new PV system or retrofit to solar PV system
commissioned after 31st December 2012
 PV system cap of 30 kWp
 Effective power reduction to 60%
 Fair value replacement guarantee (7 years)
 Disclosure of various interface points
 € Total volume of the program is € 25m
(around 8.000 systems in 2013, increase
to € 50m as of 2014 planned)
23/10/2013
14
Thank you for your attention
Bianca Barth,
BSW-Solar
Dr. Oliver Franz,
RWE Deutschland AG
Disclaimer: The sole responsibility for the
content of this presentation lies with the
authors. It does not necessarily reflect the
opinion of the European Union. Neither
the EACI nor the European Commission
are responsible for any use that may
be made of the information
contained therein.