Cranes are big structures, and as such require the right industrial lighting systems so that they can be easily seen. A crane without lights is next to invisible against the night sky, which is an extreme danger to aircraft and other moving cranes near by.
Crane lighting systems come under the aviation lighting category. Not to be confused with standard lighting designed to illuminate a lifting area, crane aviation lighting is designed so that aircraft can easily spot a tall crane from several miles away.
Crane lights are usually LED and be additionally solar-powered if the application suits it. LED lights are available various colours, common colours used are often red or white, and set in a flashing or steady configuration.
In recent history, incandescent bulbs were used to meet aviation warning light requirements. However these used large amounts of energy and needed to be regularly maintained, so a general switch to LED technology was made.