MIL-HDBK-1003/11 Section 3: INFORMATION REQUIRED FOR DESIGN 3.1 Introduction. This section defines the data that must be developed to establish engineering design bases and to evaluate between various design and ownership alternatives. 3.2 Electrical Loads. Electric loads should be determined carefully to size electric generating plant components properly. The duration and variation of electric loads should be determined to provide inputs to required life-cycle cost analyses and for various clauses when tailoring NAVFAC guide specifications, (refer to Section 1) for procurement purposes. 3.2.1 Electric Load Determination. To determine the electric load that the plant must satisfy, utilize the load estimating data described in NAVFAC DM-4.01, Electrical Engineering, Preliminary Design Considerations. For retrofit projects, the local utility may be able to supply load duration curves from actual metering records. 3.2.2 Typical Electrical Load Curves. Figure 1 is an example of a typical electrical load curve. 3.2.2.1 Growth Curve. In Figure 1(a), note the normal trend of growth in electric demands and the additional loads (steps) when new buildings or processes are added. Development of this data and preparation of the growth curve is useful in timing additions to power plant generating capacity. 3.2.2.2 Average 24-Hour Load Curves. The average of daily electrical demands in Figure 1(b), showing 24-hour variation in seasonal demands, is very important. Such curves are useful in determining load factors, the duration of certain demands, and in dividing the total electric load among plant units. This information is a necessary factor in life-cycle cost analyses to be conducted when selecting among alternative designs and equipment configurations. 3.2.2.3 Annual Load Durations Curves. Plot the duration in hours, of each load during a year for both present and future load conditions. The type of curve shown in Figure 1(c) is useful in determining load factors and in sizing electric generating plant equipment. Information from this curve is also used in required life-cycle cost analyses. Durations of plant electric loads at full load, three-quarters load, and at one-half load is a required input for tailoring NAVFAC guide specifications. 3.3 Duty and Capacity Requirements for Electric Generating Plants. Sources and duty types of electric generating plants are defined in Section 2. Table 2 summarizes capacity requirements as related to each duty type. 8 . guide specifications. 3.3 Duty and Capacity Requirements for Electric Generating Plants. Sources and duty types of electric generating plants are defined in Section 2. Table 2 summarizes capacity. ownership alternatives. 3.2 Electrical Loads. Electric loads should be determined carefully to size electric generating plant components properly. The duration and variation of electric loads should. new designs of prime duty diesel -electric generating plants. Cogeneration may be considered for existing plants if proven economically viable. Standby/emergency plants will rarely justify use of