Grid code specifications for grid energy storage systems

The European grid connection network codes do not currently set any requirements on grid energy storage systems. The Grid Code Specifications for Grid Energy Storage Systems SJV2019, required by Fingrid Oyj, were established taking into account the shared goals of European grid connection network codes: to guarantee equal and non-discriminatory conditions for competition on the internal energy market, to ensure system security and to create harmonised connection terms for grid connections.

The Grid Code Specifications for Grid Energy Storage Systems are set for converter-connected grid energy storage systems which are to be connected to the Finnish power system and which provide system services.  In addition to these Specifications, connecting parties shall fulfil Fingrid’s General Connection Terms (YLE) valid at the time of connection, the terms specified in the Main Grid Contract and the connection terms set by the relevant network operator.

The requirements have been set on the basis of the connection technology which is identical to power park modules. If other types of grid energy storage systems are to be connected to the power system, Fingrid will determine their requirements separately.

Nationally, the purpose of the Grid Code Specifications for Grid Energy Storage Systems is to ensure that:

• the grid energy storage system withstands the voltage and frequency fluctuations occurring in the power system,

• the grid energy storage system supports the operation of the power system during disturbance situations, and works reliably during and after such situations,

• while connected to the power system, the grid energy storage system does not cause any adverse impacts to the other installations connected to the power system, and

• the relevant network operator and Fingrid obtain the data on the grid energy storage system, necessary in the planning of the power system and its operation and in the maintaining of system security.