The department of energy and climate change (Decc) said the new transmission constraints licence condition had been laid before parliament, would come into force on 29 October, and be regulated by Ofgem. It will run for five, or possibly seven, years.
The new rule aims to makes it harder for generators to make money when they are not able to use the transmission system, via balancing payments from National Grid, that are then passed on to all consumers. Last financial year those charges, or constraint payments, cost bill payers £324 million. That was almost double payments made in 2010-2011 (some £170 million). Decc said the new rules could save up to £300 million over five years.
Ofgem will regulate the licence condition. See the consulation here.