How Power Plants Generate Electricity: Part II

Subtitled: "HOW to SPIN a GENERATOR"

You learned from the previous post that Faraday's generator (dynamo) is the machine used by virtually all power plants (except PV solar) to generate the current electricity that powers the modern world. Remember where we left off: in order to generate the voltage that produces current electricity, a large coil of copper wire must spin within the magnetic field of a powerful magnet.

So the question remains: How is the force required to spin a large industrial sized generator produced in power plants?

The answer is simpler than one might imagine.

First, a very large metal fan blade (similar to a pinwheel) called a "turbine" is attached to the rotational shaft of the large coil of copper wire inside the generator.

Then, a powerful stream of moving air or water pushes on the turbine causing it to spin (just like a pinwheel in the wind). Because the turbine fan blade is attached to the shaft of the copper coil, it too spins! Spinning copper inside the magnetic field produces the force (voltage) that pushes the copper electrons through the wire!

This begs the question: Where do power plants get the moving air or water? The simple answer is, It depends on the type of power plant. (Remember those from a previous post?)

Fossil fuel plants burn gas or coal; the heat of combustion is used to boil water. The expanding gas (water vapor) and steam produced by boiling are forced through a nozzle under extremely high pressure. This high pressure stream of hot water vapor and steam strikes the turbine blade causing it and the generator coil to spin.

Nuclear power plants use fission reactions (splitting uranium atoms) to create the heat needed to boil water. The expanding gas (water vapor) and steam produced by boiling are forced through a nozzle under extremely high pressure. This high pressure stream of hot water vapor and steam strikes the turbine blade causing it and the generator coil to spin.

Hydro-electric power plants trap a reservoir of water behind a tall dam. Valves are opened that direct a powerful stream of falling water spinning the turbine blade and the attached generator coil.

A wind powered generator spins when persistent natural winds strike the large rotor (propeller type blade) which of course is attached to the rotational shaft of the copper coil.

Wave and tidal generators use the movement of ocean water to spin submerged fan blades attached to underwater generators.

Concentrated solar power (CSP) plants boil water using lenses or mirrors that focus the heat of concentrated sunlight. The expanding gas (water vapor) and steam produced by boiling are forced through a nozzle under extremely high pressure. This high pressure stream of hot water vapor and steam strikes the turbine causing it and the generator coil to spin.

The more common PV solar power plants use photovoltaic panels to produce current electricity without any moving parts! No generator is needed as the different types of silicon in photovoltaic solar cells simply convert light energy directly into electrical energy!