  Modelling, forecasting and overall understanding of the dynamics of the power
grid and its frequency are essential for the safe operation of existing and
future power grids. Much previous research was focused on large continental
areas, while small systems, such as islands are less well-studied. These
natural island systems are ideal testing environments for microgrid proposals
and artificially islanded grid operation. In the present paper, we utilize
measurements of the power grid frequency obtained in European islands: the
Faroe Islands, Ireland, the Balearic Islands and Iceland and investigate how
their frequency can be predicted, compared to the Nordic power system, acting
as a reference. The Balearic islands are found to be particularly deterministic
and easy to predict in contrast to hard-to-predict Iceland. Furthermore, we
show that typically 2-4 weeks of data are needed to improve prediction
performance beyond simple benchmarks.
