UK-based owner Altera Infrastructure is already considering what the next generation of shuttle tankers will look like.

But the company is confronted with a familiar problem: figuring out what type of fuel they should use.

The former Teekay Offshore took delivery last year of four pioneering 130,000-dwt, LNG-fuelled E-Shuttle Tankers.

The Samsung Heavy Industries-built ships are supplied with fuel by Shell for North Sea operations.