In December, Sanxia Qingzhou 1 (Three Gorges Hydrogen Boat No. 1), a hydrogen fuel cell ship, marked over a year of safe operation. Developed by China Three Gorges Corporation in collaboration with research institutions, the ship represents years of innovation.

The vessel demonstrates a commitment to ecological prioritization and green development along the Yangtze River Economic Belt, said Ran Yichuan, deputy general manager and chief engineer of China Yangtze Power Co., Ltd.

Overcoming system compatibility issues

"Hydrogen fuel cells have mature applications in vehicular transportation, but there was no precedent for their use in ships," said Wang Zhen, a member of the R&D team.

During the initial onboard test, the hydrogen fuel cell experienced inexplicable power fluctuations. However, all systems appearing to be operating normally after thorough inspection. If left unresolved, such an issue could lead to accidents.

After repeated analyses of the systems, the team remained puzzled. Then, Wang Zhen had his eureka moment, comparing the situation to a heart transplant. "It's a system compatibility issue. The components themselves are fine, but they aren't harmonizing properly, like organ rejection after a heart transplant," Wang said.

The issue was ultimately traced to the energy management strategy of the power system. A dedicated management strategy should have been designed when the hydrogen fuel cell was plugged into the grid for the first time.

Once this was done, by optimizing the energy management strategy, the team ensured the "big heart" of the hydrogen fuel cell worked efficiently with other systems, enabling smooth and reliable operation of the hydrogen-powered vessel.

Addressing pressure challenges

In June 2023, just before its maiden voyage, the hydrogen boat's alarm sounded, signaling excessively high pressure at the hydrogen pipeline inlet of the fuel cell.

This not only shut down the fuel cell, but also raised safety concerns regarding hydrogen use.

The hydrogen storage compartment contains 32 tanks with a maximum internal pressure of 35 MPa, while the pressure at the hydrogen pipeline inlet of the fuel cell must be maintained at 0.6 to 0.8 MPa. A pressure reduction device is required to bridge this gap.

After replacing the pressure regulator valve, the fuel cell resumed operation. However, a few days later, the system alarmed again, indicating persistently high hydrogen pressure.

"Could the solution lie beyond the pressure regulator itself, perhaps in the pipeline system?" Wang Zhen asked. This question led the team to pinpoint the root cause.

The team revised the purging process accordingly. After rigorous testing, the issue was resolved.

Innovating hydrogen refueling solutions

While hydrogen production, compression and storage have mature solutions, refueling ships with hydrogen posed a new challenge, according to Guan Sumin, a researcher at China Yangtze Power Co., Ltd.

Compared to hydrogen vehicles, ships require larger hydrogen volumes and must accommodate seasonal water level changes and significant movement during docking, according to Guan.

The solution came in the form of a "folding mechanical arm pulling high-pressure hoses," enabling flexible hydrogen refueling within a horizontal range of 10 meters and a vertical range of 5 to 13 meters.

Having overcome challenges in energy management, safe operation and hydrogen refueling, Sanxia Qingzhou 1 now operates successfully between the Three Gorges Dam and Gezhouba Dam. It performs tasks such as transportation, inspection and emergency response across the Yangtze River.

Looking ahead, Ran said, "We will focus on hydrogen production, refueling, storage and utilization, exploring diverse applications of hydrogen energy to contribute to the protection of the Yangtze River and the realization of China's dual carbon goals."