Mitsui OSK Lines (MOL) has ordered two 89,900-dwt coal carriers at compatriot shipyard Oshima Shipbuilding, it said Thursday.

The two ships have been ordered on the back of long-term contracts with Electric Power Development Co and Hokuriku Electric Power Co to ship coal from overseas to their power plants in Japan.

The ships will be built to what is described as a “next generation” design dubbed EeneX, which was unveiled earlier this year.

MOL said the EeneX series was designed in pursuit of the “optimal coal carrier” for electric power companies in Japan.

The shipowner said it anticipates “ongoing orders” for EeneX vessels and expects them to play a leading role in its coal carrier business.

MOL said the EeneX carrier design reflects its “proactive stance” in providing safe, reliable, and stress-free transport of resources and energy.

Financial details of the newbuilding contracts and the dates of delivery were not disclosed.

The vessel’s design is said to draw on the extensive knowledge of coal carriers by several Japanese shipyards as well as MOL’s know-how in ship operation.

The main characteristics of the EeneX design include the adoption of a double-hull structure which allows the cargo holds to have completely flat sides.

This is said to eliminate the work of scraping out coal, which in turn boosts the efficiency of discharging operations and speeding up cargo handling.

Discharging operations are said to be further improved by the use of a semi-box shape hold which prevents cargo from accumulating inside.

The design has also eliminated the ballast hold, which on conventional coal carrier designs are sometimes filled with ballast water to maintain the ship’s stability during ballast voyages.

MOL said this design concept saves the effort of preparation time for ballasting into cargo holds and reduces the risk of salt and rust contamination due to rust.