N° 20-10
Sol-ion, Europe’s largest PV energy conversion and storage project, moves
into field trial phase
• Close collaboration between industrial partners Saft, Voltwerk and Tenesol has
resulted in the successful development of a prototype integrated energy kit suitable
for production on an industrial scale
• EU-backed project is now moving into field trial phase with 75 Sol-ion energy kits
being deployed in France and Germany from mid-2010 onwards
Munich, June 10, 2010 – Saft, Voltwerk and Tenesol, industrial partners in the EU-backed Sol-ion
project, have successfully completed the development phase by creating an integrated energy
conversion and storage kit, capable of production on an industrial scale, for decentralized on-grid,
residential solar photovoltaic (PV) systems. The project, which commenced in August 2008, is now
moving into its test and evaluation phase. This involves the deployment of 75 Sol-ion energy kits for
field trials across France and Germany.
The Sol-ion trials will see Li-ion (lithium-ion) batteries used in PV systems on the largest scale ever
tested in Europe. The trials will be used to assess the performance of the technology, its economic
viability, the added value of energy storage in an on-grid system and the benefits to stakeholders.
‘The key to the success of the Sol-ion project is the way that all the individual partners, both from
industry and from the research institutes, have come together in close collaboration to function as a
seamless team. So rather than each partner providing a separate element – batteries, energy
conversion and system management – and then bringing them together, we have focused right from
the very start on the delivery of a comprehensive, fully-integrated, optimized solution’ says Michael
Lippert, Marketing Manager of Saft’s Energy Storage activities. ‘We are very excited to be moving into
the field trial phase as this will provide invaluable practical experience and feedback that will help
refine our approach as we move a step closer towards making PV energy storage kits commercially
available.’
Time-shifting
Currently, the majority of grid-connected PV systems do not include energy storage and the electricity
produced is fed into the grid directly, in real time. The advantage of the Sol-ion energy conversion and
storage concept is that solar energy can be ‘time-shifted’ to periods of peak demand or when there is
no sun, allowing self-consumption or grid support. The field trials will demonstrate the benefits to the
environment and to stakeholders of storing PV energy. One key benefit will be to reduce the impact of
intermittent injection to power grids, thus allowing a higher penetration of PV energy in the electricity
mix.
Sol-ion kit
The Sol-ion kit has been developed to accommodate PV energy production of 5 kWp (peak) with a
battery rated from 5 to 15 kWh and a nominal voltage of 170 V to 350 V. Li-ion is the only technology
that meets the project’s need for 20-year battery life in demanding environmental conditions.
The energy conversion and system management systems are designed to handle four system
functions: multidirectional energy flows; self-consumption; grid support; back-up. They are also
intended to handle requirements for demand side management such as control over storage and
loads using smart metering, and integration within future smart grids that will need to handle demand
response and dynamic pricing.
The Sol-ion battery is based on Saft’s high energy Li-ion modules, with a nominal voltage of 48 V and
2.2 kWh capacity. These compact, maintenance-free modules feature an advanced and robust
industrial design, and they can easily be connected in series or parallel to create the desired voltage
and capacity for each installation. Saft’s Li-ion technology has already proven an impressive 97%
energy efficiency in a recent 2 years field demonstration in residential PV systems in Guadeloupe.
Partners
Saft’s technology partners in the Sol-ion project are leading PV systems providers and integrators:
Germany’s Voltwerk has installed over 70,000 PV systems; France’s Tenesol supplies integrated PV
systems and also manufactures solar panels. E-ON, the German utility, three German research
institutes (ISEA, Fraunhofer IWES and ZSW) and INES-CEA, the French research institute, are also
associated with this project.
Sol-ion has been recognized by the EU/Eureka/Eurogia programme and has the support of the
French Ministry of Economy, Finance and Employment and the German Ministry of Environment.
About Saft
Saft (Euronext: Saft) is a world specialist in the design and manufacture of high-tech batteries for
industry. Saft batteries are used in high performance applications, such as industrial infrastructure
and processes, transportation, space and defence. Saft is the world’s leading manufacturer of nickel
batteries for industrial applications and of primary lithium batteries for a wide range of end markets.
The group is also the European leader for specialised advanced technologies for the defence and
space industries and world leader in lithium-ion satellite batteries. Saft is also delivering its lithium-ion
technology to the emerging applications of clean vehicles and renewable energy storage. With
approximately 4,000 employees worldwide, Saft is present in 18 countries. Its 15 manufacturing sites
and extensive sales network enable the group to serve its customers worldwide. Saft is listed in the
SBF 120 index on the Paris Stock Market.
For more information, visit Saft at www.saftbatteries.com
About Voltwerk electronics GmbH
Voltwerk electronics GmbH is an internationally successful manufacturer of string and central
inverters, tracking systems and facility monitoring systems. All its products are developed and
manufactured in Germany. Voltwerk‘s award-winning products have been installed worldwide in
systems with a total of more than 500 MW of generating capacity. Voltwerk is a provider of innovative
solutions and pioneering methods for highly efficient photovoltaic systems. Voltwerk’s success is
based on precise knowledge of the markets and intensive collaboration with customers and
engineering teams across the world. Voltwerk is represented in Bad Vilbel and Hamburg and has
sales and service support in all the major European markets. Voltwerk electronics GmbH currently
has nearly 100 employees. For more information visit Voltwerk at www.voltwerk.com.
About Tenesol
A rapidly expanding global player in the field of solar energy (with a turnover of €249 million in 2009,
+29%), Tenesol works on behalf of businesses, local authorities and private individuals. For more
than 26 years, Tenesol has been engineering, designing, manufacturing, installing and managing
solar energy systems including production and consumption of supplied systems (Off-grid sites,
general grid supply via direct connection, solar water heating) for its customers around the globe. A
benchmark player in its sector, Tenesol currently has a staff of over 1,000 employees across 20
subsidiaries including 2 production facilities. For more information visit Tenesol at www.tenesol.com.
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Press contacts
Jill Ledger, Saft Communications Director, Tel: + 33 1 49 93 17 77
e-mail: jill.ledger@saftbatteries.com
Marie-Christine Guihéneuf, Saft IBG Communication Manager, Tel: + 33 1 49 93 17 16
e-mail : marie-christine.guiheneuf@saftbatteries.com
Andrew Bartlett, Six Degrees, Tel: + 44 (0) 1628 480280
e-mail: andrew.bartlett@sixdegreespr.com
BACKGROUND INFORMATION
The role of each partner
Saft
Saft is responsible for the design and manufacture of the energy storage system. The battery is based
on Li-ion battery modules connected in series to obtain the energy and voltage required by the
application. This concept provides a high level of modularity offering a wide energy window without
additional development. Each module includes an electronic board for data acquisition (voltage,
temperature, ..) and cell balancing in order to optimise the battery life time and to allow
charge/discharge control, state of charge measurement, etc.
This electronic board is connected to the system management function that controls the battery. The
interfaces have been developed in cooperation with Tenesol and Voltwerk.
Saft is delivering the batteries both to Voltwerk and Tenesol. These two PV system integrators will
produce the other components and will assembly the Sol-ion kits (battery + inverter + system
management).
Voltwerk and Tenesol
With their extensive knowledge in the production of inverters, Voltwerk and Tenesol have specified
and developed the inverter and the energy management system to meet the customers’
requirements. The system design allows the inverter to either feed the electrical power into the public
grid or store it in the battery for later use.
Voltwerk is producing and installing 25 systems in Germany. Tenesol will produce and install 50
systems in various demonstration sites in mainland France and overseas departments. Finally, field
test demonstration supervision and data acquisition will be carried out for system monitoring and
future system improvements
E-ON
E-on is providing access to its network in Germany and is contributing to the development of the
system’s interface with the network.
Research institutes
These organisations are responsible for modelling the system and its impact on the network, and for
the analysis and utilisation of the test results.
Organisations involved in the project
Partner
Saft – Project coordinator
Voltwerk
Tenesol
E-ON
Fraunhofer IWES
ZSW
ISEA
INES-CEA
Core business
Batteries
Renewable energy products integrator
PV systems integrator
Utility
Research Institute
Research Institute
Research Institute
Research Institute
All the partners have confirmed their strong interest in the development of grid connected PV
systems, associated with a storage function and recognize that this concept offers new business and
market perspectives.
The role of energy storage in renewable energy systems
Example of residential PV system with energy storage
PV installations with a permanent connection to the electricity grid are categorised as ‘on-grid’
applications. This is the most popular type of solar PV system for homes and businesses in the
developed world. PV can be installed on top of a roof or integrated into the roofs and facades of
houses, offices and public buildings. An inverter is used to convert the DC power produced to AC
power for running normal electrical equipment.
Private houses are a major growth area for roof systems as well as for Building Integrated PV (BIPV).
A typical 5 kWp panel in southern Germany delivers approximately 5,000 kWh/year – sufficient to
supply nearly all the annual electricity needs of an energy conscious household.
Connection to the local electricity network allows any excess power produced to be sold at peak
hours to the utility. Electricity is then imported from the network outside daylight hours.
The role of energy storage in an on-grid application is to store excess PV energy until it is needed.
Effectively, energy storage will ‘time-shift’ PV energy produced during the day, peaking at noon, to
make it available on demand. This will both maximise local consumption and enhance the efficiency
of the PV system. Surplus energy can also be fed back into the grid, for which the owner of the PV
system would be remunerated at a higher tariff.
Energy storage will also increase security of supply while making individual consumers less
dependant on the grid. It will also help to boost the development of energy self-sufficient houses and
buildings and contribute to the continuous growth of PV as part of the global energy mix.
The main benefit of on-grid energy storage for utilities is that it will reduce the peak load on their grid
while at the same time making PV a source of predictable, dispatchable power that they can call on
when needed. Reduced grid losses, i.e. the energy lost by transporting power from a centralised
generator to the point of use, will result in some energy savings. Savings due to reduced consumption
in PV powered households are anticipated to be 10 to 20 per cent.
Rationale for on-grid energy storage
Household
The change in emphasis for on-grid PV production has created an increasingly sound rationale for
energy storage that maximises local consumption by time-shifting PV power from the peak production
to the evening, when it is most needed. Furthermore, the more of its own-produced power that the
household uses, then the more independent it becomes from the grid and the more secure its supply.
Energy storage will also enhance the efficiency of PV production and will play a role in improving
power quality and power ability.
Any surplus energy can also be injected into the grid for which the household will be paid at a high
tariff.
Utility
The utility will also benefit from its consumers having energy storage since this will reduce peak loads
on the grid. It will also enable it to make use of PV as a predictable, dispatchable, form of power. The
utility will be able to call on this stored energy at periods of high demand. Yet at periods of peak
production and low demand, the utility will not have to accept the excess power, and this will avoid
any potential overloads on the grid.
Socio-economic impacts
Energy storage could offer a number of socio-economic benefits. Mainly, it will help to stimulate the
continuous growth of PV as part of the overall energy mix. It will also help to reduce grid losses and
encourage reduced consumption in PV households.