The laying of a £30m undersea power cable linking Guernsey to Jersey has been completed.
The cable will restore Guernsey to the European grid, after faults to existing infrastructure meant the island had burn oil for more than a year.
Once it is operational next month, Guernsey's grid will return to being 90% supplied by French nuclear and renewable energy.
Guernsey Electricity said the cable would also increase "energy security".
The NKT Victoria, a 140m (450ft) ship based in Sweden, began laying the cable on Saturday, contending with strong currents between the islands.
The old cable, installed more than 20 years ago, had three faults between 2012 and 2018 which cost £14m to repair.
The build-up of damage to the previous cable meant that Guernsey Electricity decided that additional repairs to the cable would not be cost-effective in February.
The company's chief executive Alan Bates said they were also aiming to install a cable linking the island with France by the mid-2020s.
That second project is estimated to cost £85m and could potentially require government backing to complete.
Mr Bates said the company were in the process of discussing how to fund it with the States of Guernsey, their principle shareholder.
Deputy Barry Brehaut, president of the Environment and Infrastructure Committee, indicated the States could support installing a direct link.
Mr Brehaut said the purpose of both projects was to ensure "security of supply" for the island's power grid, as well as furthering the process of "decarbonisation".
"If you're connected to the European grid and you're not burning heavy fuel oil, then that lowers your emissions massively," he added.