Europe’s biggest ethane tank, at the Grangemouth petrochemical complex in Scotland, has a new roof.

Chemical company Ineos said last week that the 330-ton roof was floated up almost 150 feet on nothing more than a cushion of air, with four low-pressure fans lifting the structure into position.

The storage tank at Grangemouth is designed to hold more than 60,000 cubic meters of ethane imported from the United States to replace declining North Sea supply. It is part of Ineos’ $1 billion global project to get U.S. shale gas to Europe.

John McNally, CEO of INEOS O&P UK, said: “This is a landmark day for Grangemouth. We know that U.S. ethane has transformed U.S. manufacturing and now Scottish industry will benefit as well. This will secure a cost-effective supply of ethane for the next 15 years, and give a sustainable base for Grangemouth for that time.”

Ineos has agreed contracts to access a 100-mile pipeline from the Marcellus Shale in western Pennsylvania to the Marcus Hook gas terminal close to Philadelphia. The company has also commissioned eight Dragon class ships to carry liquefied shale gas ethane across the Atlantic.

In Europe, Ineos has built two new import terminals to receive the gas: one at Grangemouth and the other at Rafnes in Norway.

McNally added: “Bringing U.S. ethane to Europe is a huge undertaking involving Ineos experts from across the globe. To raise the roof of this huge tank means that yet another milestone for the project has been reached. It is still early days on this project as we now set to work on the internal structure of the tank and the surrounding infrastructure.”

The first delivery of U.S. ethane is expected to arrive in Grangemouth in the second half of 2016.