Diesel generators are used for:
- back-up power generation
- regular power generation
- peak shaving
When used for back-up power generation in case of a grid malfunction, the diesel generator either turns itself on automatically or is operated manually.
When used for regular power generation, as a prime generator, diesel generators are used when the national grid is unusable or if it is difficult or inefficient to connect to it. The generator is also used, when the connected loads are so large that their effects would disturb other users in the grid.
Peak shaving is needed when an electricity contract includes a surcharge for surpassing a certain efficiency limit, particularly if the surcharge is large enough in comparison to the yearly electricity bill. Peak shaving is often used in connection with back-up power generation.