  Since intermittent and highly variable power supply is undesirable,
quantifying power yield fluctuations of wave energy converters (WECs) aids with
assessment of potential deployment sites. This paper presents analysis of
3-hourly, monthly, seasonal, and inter-annual variability of power output of
the M4 WEC. We compare expected performance from deployment at two wave energy
hotspots: off Albany on the south-western coast of Australia and off the
European Marine Energy Centre (EMEC) at Orkney, UK. We use multi-decadal wave
hindcast data to predict the power that would have been generated by M4 WEC
machines. The M4 machine, as a floating articulated device which extracts
energy from flexing motion about a hinge, is sized according to a
characteristic wavelength of the local wave climate. Using probability
distributions, production duration curves, and coefficients of variation we
demonstrate larger variability of the 3-hourly power yield at Orkney compared
to Albany. At longer timescales, seasonal trends are highlighted through
average monthly power values. From a continuity of supply perspective, we
investigate occurrences of low production at three different threshold levels
and calculate duration and likelihood of such events. Orkney is found to suffer
from more persistent lows, causing a more intermittent power output. We also
consider the effect of machine size on its power performance. Smaller machines
are found to more effectively smooth out the stochastic nature of the
underlying wave resource.
