1.4.1. Electricity supply chains
To carry out energy conversions to produce electricity, several supply chains can be considered, depending on the use or not of electronic power converters.
The most frequently used electricity generation cycle requires a heat source to heat the water, in order to obtain vapor under pressure. By expanding in a turbine, this vapor drives an alternator, which generates electricity. After passing through the turbine, this vapor is condensated with the help of a cold source, which is generally water (river, sea) or air in cooling towers. Figure 1.1 represents the conventional cycle of electricity generation.
When the heat generated by the vapor condensation is recovered for heating needs, we can speak about cogeneration.
The heat source is generally obtained by the combustion of fossil fuels (oil, gas, coal) or by a nuclear fission reaction in reactors designed to control the extent of this reaction.
The fossil fuels or uranium used in conventional cycles can be replaced by some renewable energy sources. The heat source can then be obtained by:
– biomass combustion (wood, biogas, organic waste);
– the heat found in the depths of our planet, either by directly pumping hot water towards the surface or by exploiting the high temperature of the ...