LONDON (Reuters) – BP and its partners have given the green light for the development of a large gas project off the coast of Mauritania and Senegal, a first for the two West African nations.

The Greater Tortue Ahmeyim development, Africa’s deepest at 2 kilometres below the sea’s surface, will consist of a complex floating vessel with a plant to super-chill natural gas into liquid, BP said in a statement.

This is the second major LNG project to get the go-ahead this year as energy companies bet on a sharp rise in gas demand, with rival Shell also deciding to press on with the development of a plant in western Canada.

The Tortue floating liquefied natural gas (FLNG) facility will produce 2.5 million tonnes of LNG per year. The field holds total gas resources estimated at around 15 trillion cubic feet.

Work on the project will begin in the first quarter of 2019, and first gas is expected to be produced in 2022.

The Tortue go-ahead was given after the governments of Mauritania and Senegal reached an agreement over the sharing of production from the development.

BP is the project’s operator, with a 60 percent stake in the development in Senegal and 62 percent in Mauritania. Other partners include Kosmos Energy, with a 30 percent stake in Senegal and 28 percent in Mauritania.

Societe des Petroles du Senegal (PETROSEN) and Societe Mauritanienne Des Hydrocarbures et de Patrimoine Minier (SMHPM) each hold a 10 percent stake on their side.

BP’s trading arm has been selected as the sole buyer of the project’s LNG.

Additional reporting by Shadia Nasralla; Editing by Jan Harvey