Lighting in the data center has been a target in data centers for a while, as they can have upwards of 1.5 watts per square foot of white space. While this power density may seem small by comparison with the computing loads, any lighting with over 1.0 watts per square foot is likely higher than needed. For a data center the exception is enough task lighting to allow work in the aisles as needed. But most of the time the lights aren’t needed; if you’re not doing it already, turn them off when you can.
The lights in the data center are likely fluorescent, which is more efficient than incandescent, but even with these there are big differences. T12 types of fluorescents should be replaced with T8 or even better T5. The number refers to the tube diameter, and the smaller diameter lamps have better efficacy (lumen-to-watt output).
LED lighting has caught on since the prices have reduced dramatically over the last decade. They are brighter, easier to set up, control, replace, and have little wasted heat output. If you have the choice for an upgrade in your building, ask for LEDs as the solution instead of other solutions.
More advances are coming and even now organic LED (OLED) has taken off, as the output is higher while requiring even less energy. Plus the heat is reduced too, making them them the next likely candidate to replace all of your building lighting in the coming years. But even with the newer technologies, off still uses less energy.