The regulator has approved the Transmission Network Use of System (TNUoS) charging system known as WANM 2, which would split the TNUoS into two parts: the peak security tariff and the year round tariff.
The decision document stated this option was approved because “intermittent generators are not assumed to contribute to meeting peak security” demand, while conventional generation would.
Within the year-round tariff, there will also be two elements: shared and non-shared.
This refers to generators’ ability to “share transmission capacity”, which depends on the concentration of types of generation in an area.
It recognises that it is more efficient to built transmission capacity in areas of high region of low carbon generation because this type of plant is likely to generate at the same time – such as when the wind blows – and is more expensive to constrain off the system.
Once the proportion of low carbon generation in an area exceeds 50 per cent, then part of the year round tariff will be classed as “non-shared”.
The new regulatory regime will be implemented from 1 April 2016.