Environmental Engineering Reference
In-Depth Information
2
Features of Conventional and
Renewable Generation
2.1 Introduction
The purpose of this chapter is to describe the essential features of the different electricity
generation plant, so that the role of the renewable sources and how they might be integrated
into the electricity supply system can be better understood. The main features of conventional
sources are dealt with in one section and in less detail. Such sources supply the overwhelming
proportion of energy in power systems in which renewables are now being integrated but are
themselves not the focus of this topic. Such plant will remain for a long time to come and
in the transition to a sustainable supply system they will need to complement the growing
proportion generated from renewable sources. It is therefore essential that the reader has a
basic understanding of conventional sources and their characteristics. Each of the renewable
energy sources is treated in greater length and separately to refl ect their rather diverse
characteristics.
First the rather obvious fact should be remembered that due to conservation of energy the
time varying power demand of the consumers should be continuously matched by the gener-
ated power. In this situation, generation is said to be load following . How this is done and
what happens when exact balance is not achieved is the topic of the next chapter. Conven-
tional sources, taken here to include both fossil fuelled and nuclear generation, in general
produce a given output when required to by the operator and so can be dispatched , 1 whereas
most renewable sources generate according to the time varying strength of the renewable
energy source. These time variations are particularly noticeable in the case of wind, solar,
wave and tidal power, although they are different in the extent to which the variations can
be predicted, a factor that will turn out to be signifi cant for effi cient operation of the power
system. Conventional generation in itself is neither instantly dispatchable nor completely
fl exible; it takes time to prepare large thermal plant for full load output and such plant are
1 Dispatching is the planned allocation of plant to meet expected future loads on the system.
 
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