Estimation and Negative Consumption

In some cases, a service point may be fitted with its own renewable energy source such as wind turbines or solar panels. The energy generated at this service point, as well as any energy used, could possibly be measured by a single meter, with the energy generated being netted against the energy used (a situation also referred to as net-metering). When the energy generated exceeds the energy used, negative consumption can result.

The possibility of negative consumption occurring at a particular SP/meter combination is indicated by the presence of a characteristic on the SP that identifies it as one that has generation capacity, as well as a characteristic on the meter type that identifies the meter as one capable of rolling backwards. Both characteristics must be present before negative consumption is allowed for that SP/meter combination. These characteristic types and values are defined on the Meter Management Options Feature Configuration. The following points describe the various Option Types that must be defined if negative consumption is allowed by your implementation:

• Negative Consumption SP Characteristic Type. This option indicates the characteristic type used on service points to denote generation capacity.
• Negative Consumption SP Characteristic Value. This option indicates the characteristic value used on service points to denote generation capacity.
• Negative Consumption Meter Type Characteristic Type. This option indicates the characteristic type used on meter types to identify meters capable of rolling backwards.
• Negative Consumption Meter Type Characteristic Value. This option indicates the characteristic value used on meter types to identify meters capable of rolling backwards.

Because the factors that cause a meter to roll forward are very different from the factors that cause it to roll backward, it is impracticable for the estimation algorithms to try to derive an estimate in situations where negative consumption is allowed. The estimation rules simply cannot combine the effects of all these disparate factors into one meaningful figure. By extension, the same issue applies to the determination of high/low factors. Besides the fact that high/low validation is impossible without first obtaining an estimate, a meaningful set of high/low factors cannot be determined when it is not known how energy generated at the service point may have affected the consumption in the first place. Therefore, no estimation is done by the system for SP/meter combinations that allow negative consumption. Reads that belong to these SP/meter combinations are also excluded from the trending process so as not to skew the rest of the estimates for a certain trend area and trend class.