ABSTRACT
Electric consumers require power, whether delivered from the utility grid or generated locally by distributed sources, in order to help accomplish the uses for which they need energy. Their need for electric power, and the value they place upon its delivery to them, has two interrelated but fundamentally separate dimensions. These are the two Qs: Quantity, the amount of power needed, and Quality, the most important aspect of which is usually dependability of supply (reliability of power supply, or availability as it is often called). The relative importance of these two features varies from one consumer to another depending on their individual needs, but each consumer finds value in both the amount of power he obtains, and its availability as a constant, steady source that it will be there whenever needed.
