TRIAD
Triad Demand is measured by the National Grid as the average demand on the national transmission system over three half hours between November and February (inclusive) in a financial year. These three half hours comprise the half hour of system demand peak and the two other half hours of highest system demand which are separated from system demand peak and each other by at least ten days. A customer’s triad charge is calculated by averaging the customer’s actual demands at the times of the national grid triad demands & multiplying by the triad charge applicable to their transmission zone (as published by National Grid).