Automatic frequency restoration reserve

In 2013, the Nordic power system introduced a new type of reserve, Automatic Frequency Restoration Reserve (aFRR). Its purpose is to return the frequency to the nominal value of 50 Hz. aFRR is a centralized automatically activated reserve. Its activation is based on a power change signal calculated on the base of the frequency deviation in the Nordic synchronized area and sent by the TSO. The minimum size of regulation is 5 MW and full activation time 5 minutes.

Fingrid procures aFRR reserve in the hourly market and from other Nordic countries. aFRR is only procured for certain morning and evening hours which are informed in advance. Operators can submit bids to the hourly market separately for upward and downward capacities. In addition to the capacity payment, the operator receives a separate energy compensation based on regulation carried out.