Base Load, Peak Load, and Load Factor

Base Load, Peak Load, and Load Factor

What are Base Load and Peak Load?
Load, in electrical engineering, is the amount of current being drawn by all the components (appliances, motors, machines, etc.).

The load is further categorized as base load and peak load depending upon the nature of the electrical components connected. As you may be familiar, all electrical appliances at your home do not run at all times.

A toaster or microwave oven may be used for a few minutes, a television or computer may be used for a few hours, lighting in the house is only required during the evening and so on.
There are several appliances which keep running at all the times, no matter what. The refrigerator, for example, has to be plugged in at all the times. Another such example is the heating, ventilation and cooling systems in the house (HVAC system).

Peak Load and Base Load defined
Baseload is the minimum level of electricity demand required over a period of 24 hours. It is needed to provide power to components that keep running at all times (also referred as continuous load).

Peak load is the time of high demand. These peaking demands are often for only shorter durations. In mathematical terms, peak demand could be understood as the difference between the base demand and the highest demand.

Now going back to the examples of household loads: microwave oven, toaster, and television are examples of peak demand, whereas refrigerator and HVAC systems are examples of base demand.

Load Factor
Load factor is the ratio of average electricity use vs. maximum electrical demand for a given time period. For example, if you use 60.8 kWh of electricity in a 24-hour period, your average electricity use is 2.5 kW per hour (60.8/24). If during this period, your electrical demand spikes to a peak of 8.6 kW even briefly, your load factor is only 29.1% (2.5/8.6).

The closer your load factor is to 100% (load factor 1.0) the better. On the other hand, the lower your load factor percentage, the more you pay in demand charges. Why? Because your electric utility must ensure it has the generation capacity to meet your peak demand even if you need it for only a short time. This capacity is expensive to maintain--and guess who ultimately pays for it.

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