Triads or TNUoS (Transmission Network Use of System Charges) are one of the most valuable demand response activities in the market and have been used for many years to reduce stress on the grid over the winter months when the country uses the most electricity.
Triads apply to all businesses with HH meters and focus on the three half hour periods with the highest demand over November, December, January and February. Each Triad is separated by at least ten clear days and is calculated after the end of February each year.
Businesses are charged a Triad rate based on their consumption during these three highest system peaks. As Triads are not known in advance, businesses are issued with forecasting notices, often by their supplier when the system is likely to be under stress. To avoid the Triad costs, businesses reduce their electrical load on high likelihood days to increase the chance of registering low load on the actual Triads when calculated in February.