Is there a way to estimate increasing electricity use in our data center when purchasing a generator for disaster preparedness? We don't want to buy something now, have it sit unused for three years and when it is time to use it find that it is no longer adequate.
Begin by identifying all the devices that will be powered by the generator. Determine the power required for each device, in watts, and add these figures to determine the maximum load for the generator. Add an extra 10% to 20% of power output for generator start-up. It may be advisable to enlist the services of an electrical contractor to help you determine your true loads. If you are a tenant in a building, ask the building engineer for power loads needed by the building that may apply to your space when it comes to disaster prep.
Estimating changes in power usage over time is an inexact science, but here are some tips. Regularly review your power use. Examine monthly power usage levels to see if there are seasonal variations that need to be considered. When developing three- to five-year strategic plans, determine the potential impact of planned technology and real estate acquisitions (e.g., anything that may require electrical power), and then figure out the affect those things would have on power demands. Discuss power planning with your facilities staff, as they will be responsible for procuring power systems and maintaining them when it comes to disaster prep. If you don't have an electrician on your facilities staff, consider retaining an electrical contractor.
When buying backup power systems as part of your disaster preparations, overestimate the demand by at least 30% to 40%. This way you can provide an emergency power cushion. Finally, have your facilities staff monitor power demand and provide forecasts of any possible unplanned demands that may impact the configuration of backup power supplies.
This was first published in March 2013