The following whitepaper will discuss the vital role that batteries play in supporting data centre operations. It will explain how the requirements of uninterruptible power supply (UPS) systems have altered in recent years, and what the implications are for the supporting battery technology. Details will be given about the different battery chemistry available for UPS implementation and what factors should be considered before specifying one of these options. Based on different use case scenarios, the prospective trade-offs that may be made in order to either reduce OPEX or CAPEX will then be outlined.