Silver Nova first cruise ship to power itself on fuel cells

In Germany, Freudenberg e-Power Systems and the MEYER WERFT shipyard are working to equip a new 728-passenger cruise ship with a huge fuel cell and battery system that will support all the hotel functions of the ship, promising zero emissions. A world first, sponsored with €15,6 million by the German government.

Now under construction in Papenburg, Germany, the Silver Nova will be the first generation of Royal Caribbean Group’s Nova class ships to use a new type of polymer electrolyte membrane fuel cell system with integrated reformer technology. The latter produces hydrogen to power its fuel cells from the liquified natural gas (LNG) the ship uses for its main propulsion.

Modules of 500 kW each

The large-scale fuel cell system with modules of 500 kW, each up to 4 MW combined, is called the HyCruisE research and development project. It will cover the energy production for the entire hotel operation at sea and in the ship’s port in a hybrid energy network. It can be combined with shore power if available in specific ports.

Using LNG instead of heavy fuel to power the ship’s main engines is becoming more and more a standard for half of all new cruise ships to be built since 2019. The old ones are notoriously polluting when using cheap, heavier bunker oil. This heavy fuel contains, for instance, 2 000 times more sulfur oxide than ordinary diesel.

Larger carbon footprint than 12 000 cars

They emit large amounts of CO2, with a carbon footprint of just one large cruise ship that can be greater than 12 000 cars. But also sulfur (SOx), which is responsible for acid rain. On the other hand, nitrogen oxides (NOx) cause breathing difficulties, asthma, strokes, and lung cancer. Not to mention large amounts of fine particles that enforce these health effects.

As sulfur emissions are regulated to an 0,1% upper limit within European waters, ships can use marine gas oil, a lighter oil product with a sulfur content of less than 0,1%. But this is up to three times more expensive.

Scrubbers on chimneys

Or one can invest in giant filters, called scrubbers, installed on the ship’s chimneys to eliminate up to 90% SOx and fine particles. Again an expensive solution, with 110 out of 350 cruise ships worldwide that are equipped with scrubbers.

But nowadays, LNG is seen as a more suitable solution. Liquified natural gas is still a fossil fuel, but it reduces SOx emissions by close to 100% and NOx emissions by 85-90% compared to traditional fuel. The emission of greenhouse gasses will be reduced by approximately 15-20%.

Keeping generators running

While docked in the harbor, cruise ships shut off their main engines but must keep their generators running on 10% of the fuel needed for propulsion to produce the electricity needed for all systems aboard.

In ports with lots of cruise ships, air quality still suffers massively. It frustrates inhabitants like in Venice or Antwerp, who are often confronted with low-emission zones for their cars but see heavy polluting fumes rising from the ship’s chimneys. Unless it can be plugged into the shore power on condition enough power is available. Which is seldom the case.

A ship like the Siver Nova can independently produce electricity for onboard systems. The next step will be to have the ship’s propulsion run on hydrogen to reach zero emissions at sea. Italian-Swiss shipping giant Mediterranean Shipping Company (MSC) is studying the feasibility of such an oceangoing cruise ship on hydrogen.