An undersea cable link could see Alderney supply all its electricity from renewable sources by 2022.
A tidal array is planned for the Raz Blanchard, the stretch of water between the channel island and Normandy, to primarily serve France.
The group behind the €46.8m (£40.5m) tidal array project would sell the power to Alderney Electricity.
Alderney Electricity's managing director said the island was "the wrong side of 90% reliant on fossil fuels".
James Lancaster said: "At its most basic, which is a cable connection to the tidal array and then on to the French mainland, and we see no increase in consumption or otherwise, then we expect the price of electricity to stay much the same.
"What the cable would give us is increased capacity, it also potentially opens up the avenue to, let's call it, 'all-electric Alderney'."
He said the island would save about 1.2 million litres of diesel a year.
Tim Cornelius, President of Normandie Hydrolienne and CEO of SIMEC Atlantis Energy, said the demonstration array off Normandy would show the potential of larger scale arrays in both French and Alderney's territorial waters.
"France and the Channel Islands sit on some of the best [tidal] resource in the world", he said.
Mr Lancaster said: "The cable project is not about Alderney's tidal resources... nonetheless if we ever in the Channel Islands wish to see our tidal energy resources exploited it's got to start somewhere."
He said the cable would be like those connecting Guernsey, Jersey and the French mainland.
He said sea bed surveys were needed to decide where the cable would come ashore, but his preference was for the rocky north eastern side of the island, avoiding all the beaches.
On-island fossil fuel generation would remain as a back-up in case of any failure in the cable.