The simplest answer to this common question is that a generator works by converting mechanical (or kinetic) energy into electrical energy. This is true of huge generators at power plants, commercial backup generators and small, portable models.
Using a generator does not mean you’re creating energy. The Law of Conservation (one of physics’ major laws) states that it’s in fact impossible to create or destroy energy. Instead, we’re constantly shifting energy into different forms to suit our needs.
Generators convert mechanical energy into electrical energy using electromagnetic induction. In its simplest form, electromagnetic induction uses a magnet to move electrons within a conductor, such as copper wire.
A generator’s engine uses fuel, whether diesel, gasoline, propane or natural gas, to create mechanical energy, which is then converted to electrical energy within the generator’s alternator. Mechanical energy from the engine is used to move a wire coil within a magnetic field or move a magnetic field around a stationary set of wires in the alternator. This magnetic field is produced either using a physical magnet or a magnetic field created by induction.
The electrical energy created in the alternator is measured in volts. A voltage regulator takes the “new” electrical energy and regulates how much voltage passes to your home or business. It does this with a cycle of AC to DC conversion that encourages the production of more or less energy to power the required load.
Another output of the electromagnetic induction that occurs within a generator is heat. A voltage regulator helps reduce heat production by also reducing electrical output when possible. The byproduct of heat is removed from the generator using a cooling system. In small generators, this may be a simple air intake. In commercial standby generators, water and/or hydrogen is coupled with a heat exchanger to remove excess heat.