numerous studies have analyzed the benefits of combining wind
and hydropower to provide stable power [10e12], but only a few
have addressed if, by interconnecting advantageously-distributed
wind farms, it may be possible to guarantee a certain amount of
wind power output all the time, eventually transforming wind
energy into a reliable supply. There is no clear consensus in the
literature for evaluating the contribution of wind toward reducing
the conventional capacity of power systems. In general, two parameters
for describing this contribution have been used: capacity
credit and firm capacity. Capacity credit is a measure of the ability
of a wind farm or a solar plant to contribute to the peak demands of
a power system, maintaining the same security of supply as conventional
power plants [13]. This parameter is usually expressed in
%. Obtaining the capacity credit is no easy task, since full modeling
of the power system is necessary. Several studies have analyzed the
wind energy capacity credit, in individual countries and for all
Europe [13e15]. The main conclusion was that wind power has
capacity credit but is highly dependent on the supporting electric
system, wind load factor and penetration level. On average, for a
penetration around 20%, the wind energy capacity credit could