A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems.

It generally includes redundant or backup power supplies, redundant data communications connections, environmental controls (e.g., air conditioning, fire suppression) and various security devices.

Large data centers are industrial scale operations using as much electricity as a small town and sometimes are a significant source of air pollution in the form of diesel exhaust.

Capabilities exist to install modern retrofit devices on older diesel generators, including those found in data centers, to reduce emissions.