Japan’s Kawasaki Kisen Kaisha (K LINE) has announced the development of two conceptual designs for liquefied natural gas (LNG)-driven and battery-powered bulk carriers to reduce emissions while improving operational efficiency.

The two designs have received approval in principle (AiP) from Japan’s ship classification society, Nippon Kaiji Kyokai (ClassNK).

In collaboration with Namura Shipbuilding and Taiyo Electric, K LINE developed a conceptual design for a 200,000t class capesize bulk carrier.

K LINE also made a conceptual design for a 90,000t class post-Panamax bulk carrier. It has been designed together with Shin Kurushima Sanoyas Shipbuilding and Taiyo Electric.

The Japanese firm said that the energy-saving vessels have been designed to help reduce greenhouse gas emissions by selecting low-carbon LNG as the primary fuel source.

To further enhance the design, permanent magnet (PM) shaft generator technology and lithium-ion batteries have been used.

In a press statement, the firm said: “Moreover, by utilising batteries as part of the platform for power supply on board, the aim is to further reduce emissions going forward by later adding green energy sources with energy-saving technology.”

K LINE expects the power production with shaft generator technology to improve fuel efficiency compared to power generation with a conventional dual fuel generator.

Furthermore, small-capacity batteries, said to have ‘excellent charge and discharge rates’, will be used for auxiliary power during peak hours of on-board demand. They will also be used to store surplus electricity.

The new post-Panamax carrier design also reduces emissions by using large-capacity batteries, rather than a dual fuel generator, during cargo loading and unloading.

“In addition to the equipment for greenhouse gas emissions reduction under the recent AiPs, the aim is to further reduce emissions going forward by installing various optional technologies,” the company noted.