Integration of Renewables and System Services

In Europe, TSOs must maintain their electric frequency very close to 50 hertz (Hz) and this is readily achievable when supply matches demand (load). However the introduction of non-synchronous generators such as wind energy poses challenges when integrating a large proportion into a synchronous system. At times of high instantaneous non-synchronous renewable penetration levels, frequency control becomes more challenging due in part to the presence of Rate-of-Change-of-Frequency (RoCoF) protection relays and the potential for large amounts of wind farms to shut down during a fault scenario. Therefore system services, other than energy, are required for the continuous, secure operation of the power system.

In September 2011 EirGrid and SONI commenced a multi-year programme entitled “Delivering a Secure, Sustainable Electricity System” (the DS3) programme. This DS3 programme is designed to ensure that the island of Ireland can securely operate the power system with increasing amounts of variable non-synchronous renewable generation over the coming years. The DS3 programme is critical to Ireland meeting its 2020 renewable electricity targets; 40% of electricity energy generation from renewable sources by 2020 (RES-E).

An extensive period of consultation with industry was undertaken by the TSOs (Eirgrid and SONI) on their proposals to redesign the system service arrangements in order to meet the needs of the system in 2020. On the 20th December 2013 the all-island Single Electricity Market (SEM) committee set out its decision (SEM-13-098) in relation to the technical definitions of the services. The SEM committee concluded that there is clear evidence that enhanced system services are required in order to maintain a secure and reliable electricity system under conditions of high wind penetration.

Schwungrad’s facilities will facilitate an increase in the System Non-Synchronous Penetration (SNSP) limit to 75% by 2020, reduce the curtailment of wind, provide greater investment certainty in renewable energy and enable Ireland to meet its 2020 renewable electricity targets.