Power generation by thermal power plants

Electricity generation at high power levels - several hundred megawatts - is achieved by converting the chemical energy contained in a fuel (coal, oil or gas), or nuclear energy, into heat, then mechanical energy, then electricity. Alternators are used for mechanical-electrical conversion, while thermal-mechanical conversion is carried out by steam engines (IMV) or gas turbines (TAG), also known as combustion turbines (TAC). The transformation of chemical energy into thermal energy takes place in the steam generator (GV) for IMVs, or in the furnace for TACs.

A basic understanding of how these systems work requires a return to the concepts of applied thermodynamics, which involve energy balances, entropy balances and the evolution cycles of the fluid used as the thermodynamic or working fluid: water in the case of VMIs, air, fuel and smoke in the case of TACs.

The first two parts of this article describe and analyze the operation of conventional systems. The third part is devoted to the coupling of the two systems, a coupling which enables the best efficiencies to be achieved.

As this article does not claim to be exhaustive, all presentations will remain at the level of principles. Readers are referred to specialized articles in Techniques de l'Ingénieur for more detailed technical information on these thermal machines.