This question is actually about backup power.

The owners of a go-cart track,which runs races at nite,want to know if there's some way to have a system in place to power the track lites in case of a power failure in the middle of a race.

It would have to be something instantanous,and the lighting is metal halide.

Does such an animal exist? I'm familiar with usual,residential systems,even with automatic transfer switches,but even they have a reaction time.

Please enlighten me,and thanks for any help.

Russell