A swathe of subsea power lines between Britain, Ireland and other European countries that will carry enough electricity to power millions of homes have been given the green light.

Energy regulator Ofgem approved three cables linking Britain to Germany’s, Ireland’s and Northern Ireland’s power grids and also approved lines to connect Britain’s grid with Dutch and Belgian offshore wind farms.

The projects, all of which are due to be completed by 2032, are designed to cash in on a massive planned ramp-up in UK wind power generation over the coming years, with plans to make Britain a net exporter of clean energy.

The power lines, called interconnectors, enable Britain to be more flexible with energy supply either by exporting surplus power abroad or buying it from other countries to meet its own demand.

Britain has interconnectors that can carry about 11.7 gigawatts of electricity and the new interconnectors will increase that to 12GW in 2030 and 18GW in 2032.

One gigawatt hour of electricity is enough to power about one million homes for one hour.

The interconnectors had initially been refused by Ofgem because they will add between £2 and £5 a year to energy bills from 2030 to 2035.

Akshay Kaul, Ofgem director general for infrastructure, said the regulator had only approved projects “which deliver for consumers in terms of value, viability and energy security”.

He said: “As we shift to a clean power system more reliant on intermittent wind and solar energy these new connections will help harness the vast potential of the North Sea and play a key role in making our energy supply cheaper and less reliant on volatile foreign gas markets and associated price spikes.”

He added: “With Britain expected to become a net energy exporter in the 2030s, these connections will equip us with world leading technology to export more of our surplus clean power overseas.

“They will also provide greater access to energy imports, which together with domestic low carbon energy sources such as nuclear and biomass, will provide vital back-up energy sources when renewable generation is more limited here.”

One of the interconnectors will run between East Anglia and Germany, a second will run between north Wales and Ireland and another will run between Scotland and Northern Ireland.

The other two lines are called offshore hybrid assets and will connect the UK to Dutch and Belgian grids with offshore wind farms belonging to the European countries in between.