Clean out to sea

energy concepts | Diesel engines in ships could soon be getting some competition from green technology. Diesel-powered fuel cells are clean, quiet, and reliable. A prototype is to be launched in early 2017.

A fuel cell combined with an electric motor is not only virtually silent but also significantly less trouble-prone than an internal combustion engine. thyssenkrupp Marine Systems already uses this technology very successfully in its submarines. So far surface ships are mainly powered by diesel engines. In the “SchiBZ” project, Keno Leites and his team have developed an eco-friendly alternative: a diesel-powered fuel cell. At the start of 2017 the new technology is being fitted in the freighter “MS Forester” for testing. In our interview Keno Leites explains how it works and what advantages it has over conventional diesel engines.

Can you give us an idea of what a diesel-powered fuel cell is?

Normally fuel-cell vehicles or ships are powered by hydrogen stored in tanks. We use ordinary road-quality diesel. But because no open combustion takes place, there are no emissions of nitrogen oxides, soot particles, or potentially carcinogenic polycyclic aromatics. Only carbon dioxide and steam will pass through ships funnels in the future.”

Diesel doesn’t have the greenest reputation.

That’s true. But with our project partner, the Oel-Waerme-Institut in Aachen, we’ve succeeded in converting diesel into methane, hydrogen and carbon dioxide. In this process the fuel vaporizes and a catalyst splits the long hydrocarbon chains into hydrogen and methane. That way the normally not-so-green diesel is converted into clean energy for the fuel cell – without producing so much as a milligram of soot.

“No nitrogen oxides, soot particles, or polycyclic aromatics. Only carbon dioxide will pass through ships funnels in the future.”

Keno Leiteshead of the “SchiBZ” project

So does that mean all new ships will soon be fitted with diesel-powered fuel cells?

We’re not quite that far yet. Although fuel cells are up to 25 percent more efficient than diesel engines, they’re not yet powerful enough for long-range operation: the ten megawatts and more that would require are still unrealistic with the power density of fuel cells currently available.

Are they suitable for any practical applications yet?

Yes. Fuels cells can already be used for ships that operate in port terminals or close to the coast. At the start of 2017 the 100 meter long freighter “MS Forester”, which operates from the Baltic to the Mediterranean, will become the first ocean-going ship to be fitted with our technology.

In parallel we’re working on further improvements, for example in energy efficiency. Around 50 percent of the diesel is used to produce electricity, the rest goes to waste as heat. That we really need to change!

What are you planning next?

We expect that our fuel cell technology will mainly be used to cover the “hotel load” of passenger ships in the future. By that I mean for example the kitchens, heating, air conditioning and lighting. Initially the main propulsion will continue to come from diesel engines. If our technology performs well in the practical trials, initial pilot projects with customers are planned from 2019. But first we need to see how it fares at sea.