The Lib Dem minister said families should brace themselves for “more price rises” but ruled out backing Labour’s plan to freeze prices or Tory moves to cut green taxes.
The levies already add £132 to the average bill but now Mr Davey is preparing to sign off another new tax which will hike prices even further.
The levy will pay for two new nuclear reactors at Hinkley Point on the Severn estuary in Somerset. Mr Davey said an announcement was “extremely close”.
He has been in tough talks with French firm EDF over a guaranteed minimum price for the electricity they will produce. Mr Davey will pass the cost to consumers through a levy on bills, starting in the early 2020s.
“Green” taxes will then make up a third of a family’s electricity bill – about £270.
Mr Davey said the agreement would be good news.