How is the turbo-alternators driven by?

Turbo-alternators are driven by turbines. Essentially, these machines convert the kinetic energy from steam, gas, or water flow into electrical energy through the use of a turbine connected to an alternator. In most common cases involving large-scale power generation, steam turbines are used. The steam is produced by heating water through the combustion of fossil fuels or nuclear reactions, or by capturing heat from other industrial processes. This steam under high pressure is then directed to the turbine blades, making the turbine rotate. This rotation is transferred to the alternator (essentially a generator), which converts the mechanical energy into electrical energy.