Environmental Engineering Reference
In-Depth Information
but very hard to assess in monetary terms; it is also frequently concluded that there
are less costly ways of avoiding those CO
2
costs than resorting to renewables ([
26
]
is a representative example). Most researchers focus mainly on the latter question, i.
e. the costs of grid integration. This is because by their very nature renewable
energies are intermittent and unpredictable: they depend on the vagaries of the wind
and sun, although the unpredictability applies mainly to the wind, as the sun is
variable but more predictable, at least a few days in advance, and throughout the
hours of the day. Since demand must be adjusted at all times, because electricity is
currently hard or indeed impossible to store in large amounts, the immediate
conclusion is that variable Renewable Electricity Sources (vRES) need some kind
of
generating capacity. Hydraulic energy is one possibility, but in
practice the task is usually assigned to natural Gas Combined Cycle Turbines
(GCCT), which are a fossil-fuel-based source. This may represent a substantial cost,
as this capacity must be kept waiting in
stand
-
by position
, i.e. operating but at low
levels, and for technical reasons such plants cannot be quickly started from zero on
short notice, at least at a reasonable cost.
Interestingly, from the point of view of market participants the question has been
analysed much more openly, in a manner based on the actual functioning of
electricity markets. And the fact is that experience seems to contradict academic
concerns to a large extent to judge from the high rates of penetration of renewables
achieved in some markets (Germany, Denmark, Spain and elsewhere) and the
results of some enquiries. One interesting example is a survey conducted among
system operators by the European Photovoltaic Association (EPIA): the main result
obtained is that even as it stands today the electricity network can accommodate
quite large amounts of renewable energy without signi
'
back-up
'
cant disruptions [
10
]. This
is all the more remarkable given that the actual grid is not designed for renewables.
That would require a
net at local levels -because of self-consumption and
distributed generation- and a few long distance connections capable of carrying
large volumes of electricity [
32
]. It must also be noted in passing that the cost of
investing in the network and the losses incurred in the transportation of electricity
are greatly reduced with renewables and distributed generation and consumption at
local level.
Finally, this is just one of the many externalities involved in the analysis of the
cost of renewable energies. It is signi
'
denser
'
cant, but so are many other externalities in
the present context. A brief discussion of this point follows later in this section.
Therefore, without denying their relevance, the fact that all externalities in general
are dif
cult or almost impossible to measure properly in monetary values results in
their not being considered in the present case. This is in no way to imply that they
should not be taken into account, but rather that as a
rst step it is best to have a
simple cost measure such as the LCOE or some other that can be easily assigned a
monetary value and can be used to make meaningful comparisons.
The point of view usually followed at present is that of an investor, be it a private
company, an individual, or the state. Therefore, it is not strictly cost that is being
considered but rather the price that has to be paid in the market to go ahead with the
investment in question. This is important, since the pro
t of suppliers of equipment
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