The project, which commenced in August 2008, is now moving into its test and evaluation phase involving the deployment of 75 Sol-ion energy kits for field trials across France and Germany.

The Sol-ion trials will use Li-ion (lithium-ion) batteries used in solar PV systems.

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 solar PV system and the benefits to stakeholders.

One key benefit will be to reduce the impact of intermittent injection to power grids, thus allowing a higher penetration of solar PV energy in the electricity mix.

The Sol-ion kit

The Sol-ion kit has been developed to accommodate solar PV energy production of 5 kWp with a battery rated from 5 to 15 kWh and a nominal voltage of 170 V to 350 V.

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. The compact, maintenance-free modules 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 a 97% energy efficiency in a recent 2-years field demonstration in residential solar PV systems in Guadeloupe.