The operation of a plant requires the ongoing availability of a number of utility services: Electric Power and Steam first and foremost, as vital plant arteries, but also industrial and cooling water, plant and instrument air, fuel oil and gas, nitrogen, condensate recovery, etc., examples of the most common utility systems needed for processing purposes. Utilities, however, are also the second largest operating cost component: their accurate design – often made difficult by the late and/or partial availability of a reliable Plant Utility consumption overview – is therefore essential to minimize production costs. A typical task of utility designers is to obtain the necessary info from the Process Contractors to accurately determine the capacity of the facilities: the consumption overviews provided by the Contractors are sometimes too late in coming and often rather optimistic. This involves design rearrangements during the engineering phase of the project, with schedule and cost impacts. Utility designers must properly take these problems into account, evaluating reserve capacities (or simply reserve spaces in the layout), but avoiding excessive oversizing and the unnecessary increase in investment costs. A few considerations regarding some of the above mentioned utilities are given below.