  Renewable energy sources (RES) are close to grid parity compared with
conventional generation. Therefore, it is important to consider proper costs to
assess the economics instead of technological aspects only. While some scholars
are in the opinion that RES only adds complexity - as RES production is
volatile and stochastic - others share the opinion that RES has value in terms
of energy savings, as well as capacity savings, and contributes to the
reliability of an energy system. Instead of analyzing the losses as a result of
adding RES, it should be focused on the overall system economics, as this is
more important than if more or less electricity is lost for whatever reason.
Economy of Scale (EoS) can have significant impact on project evaluation, and
therefore should be considered in medium- and long-term planning exercises. As
a result of not limiting RES to minimize losses within the system, the most
economic systems show penetration for photovoltaic of above 80 percent, and for
Wind of above 55 percent, on peak demand for both locations. This shows that
significant energy out of RES is not used during the winter, as the demand is
less than 50 percent of summer RES, adding value to the system, as RES saves
fuel and increases system reliability by decreasing the required electricity
from conventional generation. Dependent on the location, between 30 and 40
percent of peak demand on renewable technologies are required before curtailing
takes place. It looks like the concept of Effective Load Carrying Capacity
(ELCC) is not that important anymore, as prices for RES came down significantly
within the last decades. The RES quality still plays an important role but is
getting less important as RES costs are decreasing further. It is expected that
also average RES quality site will be more economic in several years.
