Energy regulator Ofgem has put forward plans to slash National Grid's budget by £185.4m.
The watchdog, which sets the amount of money granted to National Grid to look after the UK's gas and electricity networks, said the proposals were part of a mid-period review.
It means Ofgem's allowances for National Grid electricity and gas transmission price controls will fall from £16.9bn to around £16.7bn between 2013 and 2021.
The move includes cutting allowances by £168.8m for gas transmission because it no longer needs to build gas pipelines at Avonmouth.
Ofgem said it would also trim £38.1m from electricity transmission, as less fault protection work is needed due to fewer generators connecting to the high voltage grid.
But it said National Grid would be handed an extra £21.5m to help with its role of managing extra supply and balancing services as the UK moves towards a low carbon economy.
The decision on the proposals will be made in the autumn, with the changes coming into force from April 2018.
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