Renewable Energy and Transmission Networks - Green Energy and Efficiency: An Economic Perspective - page 368

of higher voltage levels or high voltage direct current (HVDC) technology, leading
to changes in the way most transmission networks are currently structured and
operated.
RES-based generation requires the support of conventional generation when
there is a lack of wind or solar radiation. The more geographically dispersed these
RES resources are, the less probable it is to face a simultaneous lack of production
from these resources. The wind will probably blow in some parts of the region and
the sun will shine in other zones of the region. But this geographically-changing
mutual support will require the existence of enough transmission capacity to cope
with all these resulting

ows. Moreover, whenever conventional generation support
is needed to cope with extreme adverse conditions (i.e., a generalized absence of
primary RES resources), the existence of a well developed and meshed network will
permit sharing these back-up generation units among the entire region.
All these features of RES generation will signi

cantly affect the way transmis-
sion networks are developed and operated, and therefore how the transmission
activity is regulated and managed [ 16 ]. The rest of the chapter is as follows.
Section 2 discusses the effect that the existence of RES generation has on the
planning of the expansion of the grid. Section 3 focuses on how access to the
transmission grid must be regulated and managed in the new context. Section 4
describes some impacts the existence of RES generation may have on the allocation
of transmission costs. Finally, Sect. 5 provides the main conclusions drawn from
our analysis.

2 Planning the Expansion of the Grid

As a result of the deployment of large amounts of RES generation, expansion
planning may probably need to take place in an integrated manner at regional level
due to the resulting increase in power ows between areas with abundant eco-

nomically ef cient RES resources and those that are lacking them [ 22 ]. At the same

time, mechanisms to manage in the long term the access of RES-based generation,
and probably also part of conventional one, to the transmission grid will become
necessary. What is more, demand for long-term transmission capacity products will
probably condition the optimal development of the grid. The format of these rights
will have to be de ned and even the mechanisms for coordination between trans-

mission and generation development will have to be revisited.
Lastly, and related to previous arguments, transmission expansion planning
algorithms will probably need to be upgraded to be able to deal with much larger
systems than those considered in traditional expansion planning exercises, while
considering a much larger set of operation situations as relevant for the dimen-
sioning of the grid.