The commercial and residential multistoried complexes normally have large generators for Lift / Elevator back-up.Though the lift operation is intermittent the generator needs to run continuously, thus burning lot of fuel and the initial investment on the generator itself is high. Also there are regular concerns of pilferage of fuel.
A UPS that is designed to handle the Elevator intermittent loads plus some emergency lighting loads would reduce the initial investment greatly and also save recurring expenses on fuel greatly.
8 Green Technologies offers such Elevator UPS for various sizes of lifts and back-up durations. These come with excellent payback periods with or without Solar charging.