ROME — Of all the alternative fuels touted as future solutions for cleaner warships, one of Europe’s shipyards is betting on cow manure.

“I see biofuels based on substances like agricultural biomass and food waste as the short-term alternative to fossil fuels for naval vessels,” said Massimo Debenedetti, vice president for research and innovation at Italian shipyard Fincantieri.

Debenedetti’s views are to be taken seriously since he oversees a series of studies that the company hopes will lead to greener naval vessels through cooperation with partner firms and its own experience with cruise ships. The company is also collaborating with the French government and industry, but above all the driving force comes from the Italian Navy — Fincantieri’s biggest military customer.

“The Italian Navy is very conscious of the need to reduce the use of fossil fuels, even if international regulations on cutting emissions only concern civil vessels,” Debenedetti said.

Biofuels are part of an ongoing study led by Fincantieri-owned propulsion firm Isotta Fraschini Motori, which aims to develop a marine engine that can use either traditional fuel, liquid natural gas, ammonia, hydrogen or biofuel.

“Apart from biomass and food waste, biofuels can derive from crops which are not fit for consumption,” Debenedetti said.

But ammonia — another possible alternative to fossil fuels — is the “toughest challenge,” he added. “When burned it produces energy, but storing it is hard and igniting it is hard.”

If biofuel has short-term potential, the longer-term challenge Fincantieri is working on is creating hydrogen-powered fuel cells for surface vessels that are similar to those used on submarines today.

“The technology is mature, but not ready for use on ships at the proper scale. Whereas you might need them to generate 100 kilowatts on a submarine, you will need tens of megawatts on a surface vessel,” Debenedetti said.

A three-year joint study launched last year by Fincantieri, France’s Naval Group and their joint venture Naviris, with funding from the French and Italian defense ministries, is exploring how fuel cells can be put onboard a warship.

“It comes down to making the system anti-shock and making it fit into limited space,” Debenedetti said. “Fuel cells take up more space than traditional propulsion, not least because of the hydrogen storage. And while on a passenger ship I might remove cabins to make room for it, I cannot on a naval vessel.”

Another study, this time with a eye on both the civilian maritime market and the defense sector, aims to progress Zeus, a program to build a 25-meter, 170-ton experimental ship to test fuel cell technology. Now under construction at Fincantieri’s Castellammare di Stabia yard near Naples, Zeus involves input from Isotta Fraschini Motori and is funded by Italy’s Economic Development Ministry.

Fincantieri believes its work on technologies for both the civil and military sector will give it an industrial advantage. “People working on both sides can swap information — the learning curve on the civil side benefits our defense work,” Debenedetti explained.

It is the same kind of synergy that saw Fincantieri use its work on passenger comfort onboard cruise ships to improve the lives of sailors on its FREMM warships — a factor that convinced the U.S. to buy the frigate.

Likewise, work to reduce noise and vibration on military vessels was used on cruise ships.

When it comes to lowering environmentally unfriendly emissions, the pressure is felt more in the civil sector, where the European Union is pushing member states to go green.

On July 26, Fincantieri, energy company Snam and cruise ship-operator MSC signed a memorandum of understanding to jointly build a zero-emission, hydrogen-powered cruise ship.

“It could be achievable by the start of the next decade, probably using fuel cells which are more efficient although more expensive and larger than a hydrogen internal combustion engine,” Debenedetti said.

Another alternative to fossil fuels, liquid natural gas is already a mature technology for cargo ships, he said, “but refueling is the issue: In the Mediterranean, the only port with LNG refueling is Barcelona.”

Even if military ships don’t face regulatory pressure to reduce fuel consumption, there is a real need to use power sparingly, as new radars and laser weapons suck up enormous amounts of energy onboard.

That has prompted another study, this time funded by the Italian Defence Ministry, to look into the use of direct current electricity onboard ships, as opposed to the more usual alternating current.

“DC allows you to manage high loads of electricity better over a short time,” Debenedetti said.

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