International shipping accounts for about 2.5% of global emissions, or about 1 billion tonnes of CO2-equivalent per year. To achieve sustainable development goals, the United Nations (UN) agency International Maritime Organization (IMO) aims to reduce greenhouse-gas (GHG) emissions from international vessels by 50% by 2050.
Last month, the IMO agreed to make an existing target legally binding to reduce the carbon intensity of shipping by 40% compared with 2008 levels in the next 10 years.
To achieve the UN’s directives, shipping leaders say the first net-zero ships must be operational by 2030.
Norway is targeting a more ambitious goal: zero emissions in cruise ships and ferries by 2026.
Shipping companies are looking to hydrogen as one of the most promising zero-emission fuels for offshore vessels.
Compared with combustion engines, hydrogen in a fuel cell can be converted to electrical energy two to three times more efficiently. Yet, only 0.002% of more than 110 million tons of the hydrogen produced per year is used as fuel.
Norwegian shipbuilding and design company Ulstein is moving toward doing its part to change that. The company’s newest addition to its X-JACK series of heavy-lift jackup designs is also its second hybrid-hydrogen design for the offshore wind industry. The J102, originally introduced early in 2019, incorporates the same design philosophy as the SX190—Ulstein’s first hydrogen-fuel-cell-powered offshore vessel—but in a wind turbine installation vessel (WTIV) that can operate 75% of the time in zero-emissions mode.
And since Ulstein used readily available technology in developing the J102, the additional cost was limited to less than 5% of the total capex.
In adapting the hybrid hydrogen design for the X-JACK series, Ulstein had design challenges to overcome. First, most new jackup designs run on a high-powered battery energy storage systems (BESS) in combination with diesel generation sets—with the capacity to later add a hydrogen-powered fuel cell system. But with its heavy weight and cost, a large BESS design is not practical for WTIVs where minimized elevated weight is essential for optimizing the variable deck load.
So rather than wait for the perfection of hydrogen-powered fuel-cell technology, Ulstein studied the operational cycle of WTIVs and the power demand in various modes.
They learned that 75% of the time, WTIVs remain in the jacked-up position performing crane operations. It was apparent then, that a combination hydrogen fuel cell system and smaller BESS would be sufficient to meet the overall power demand on board and in crane peak loads.
Hydrogen is much less dense than other fuels, requiring more storage capacity—so hydrogen fuel cell systems are typically used to power vessels on short voyages. With the J102, the modular storage layout provides the flexibility to operate the vessel worldwide, even with the limited availability of hydrogen bunker infrastructure in ports.
The vessel’s patented kite-shaped hull is sized for cost-effective installation of four to eight wind turbines and reduces weight by 10% over conventional torsion-box structures.
“The strong focus on renewable energy and emission reduction to meet worldwide climate goals should also be reflected by investments in cleaner operations when installing offshore wind turbines,” said Edwin van Leeuwen, managing director at Ulstein. “Hydrogen is one of the most promising zero-emission fuels for offshore vessels and we want to be leading in developing sustainable ships.”