LNG can also be easily combined with diesel or heavy fuel oil in a dual-fuel engine system. Customers can therefore choose from two options: pure gas systems (ship powered by LNG only) and dual-fuel systems (ship powered by LNG or marine gas oil).

As they offer the flexibility to switch between fuels, dual-fuel systems are, for example, an interesting option for ships that operate both inside and outside an Emission Control Area (ECA).

ECAs are spreading internationally. The first Sulphur Emission Control Area (SECA) in the coastal region of California was established in 2009. An extension to other coastal regions in the U.S. and Canada came into effect in August 2012.