Also, a grid operator may have higher confidence that PV or wind
power will deliver its forecasted output an hour later compared to
an open-cycle gas turbine because fueled plants are more complex
and because their failures are lumpier (more capacity fails at once)
than a diversified portfolio of small units [24]. Moreover, the “balancing
costs” of integrating variable renewables into the grid are
quite small as the efficiency losses from running some fossil-fueled
plants below their optimal load points are also modest. For example,
estimated wind integration costs associated with increased wind
energy from integration studies completed from 2003 through 2013
at various levels of wind power capacity penetration show that costs
estimated are below 9.0 €/MWh—and often below 3.8 €/MWh—for
wind power capacity penetrations up to and even exceeding 40% of
the peak load of the system in which the wind power is delivered
[7]. Of course, these values can be higher for insular systems because
of the lower number of conventional power units for matching
production and demand, as it will be discussed in this work.
However, it can be mitigated if (i) more flexible conventional power
generation is in place for achieving a higher penetration of renewable
energy; (ii) insular power systems are interconnected and, even
better, if they are connected to mainland grids [25]; and (iii) insular
grid codes (voltage and frequency operating range, active power
regulation, maximum power limitation, active power range control,
ramp rate limitation, delta control, reactive power limitation, powerfrequency
response, inertial power response and fault ride through
capability) for renewable energy technologies are introduced or
improved [26].