Diesel generator

A Diesel Generator is the combination of a diesel Engine with an electric generator (often an alternator) to generate electrical energy. This is a specific case of engine-generator. A diesel compression-ignition engine often is designed to run on fuel oil, but some types are adapted for other liquid fuels or natural gas.

Diesel generating sets are used in places without connection to a power grid, or as emergency power-supply if the grid fails, as well as for more complex applications such as peak-lopping, grid support and export to the power grid.

Sizing of diesel generators is critical to avoid low-load or a shortage of power and is complicated by modern electronics, specifically non-linear loads. In size ranges around 50 MW and above, an open cycle gas turbine is more efficient at full load than an array of Diesel Engines, and far more compact, with comparable capital costs; but for regular part-loading, even at these power levels, diesel arrays are sometimes preferred to open cycle gas turbines, due to their superior efficiencies.

Generator size

Generating sets are selected based on the electrical load they are intended to supply, the electrical load's characteristics such as kWe, kVA, var, harmonic content, surge currents (e.g., motor starting current) and non-linear loads. The expected duty (such as emergency, prime or continuous power) as well as environmental conditions (such as altitude, temperature and exhaust emissions regulations) must also be considered.

Most of the larger Generator Set manufacturers offer software that will perform the complicated sizing calculations by simply inputting site conditions and connected electrical load characteristics.

https://en.wikipedia.org/wiki/Diesel_generator