Fuel cell: CO2-free boat propulsion is presented by the Nordenham Innovation Centre

Expensive, heavy, CO2-intensive - so far, that's a brief summary of the bill for e-drives on yachts. Strictly speaking, they do more harm than good for the environment. At the same time, they usually force owners to compromise on range and speed under power. No wonder the technology has not even begun to catch on.

Two sailors want to change this, both friends for 40 years, both dissatisfied with the status quo. The impetus came from Ralf Brauner, Professor of Meteorology and Computer Science at Jade University. Two years ago, during the Round Denmark Race, he had the impulse to help water sports become more sustainable. He found a congenial partner in Dieter Sichau, Managing Director of the Innovation Centre in Nordenham. Together they launched a development that is being presented to the public for the first time today.

Drive with fuel cell without charging and conversion losses

It differs from previous approaches for e-drives on yachts primarily in that it almost completely dispenses with batteries. Instead, a hydrogen-powered fuel cell supplies the energy required for the engine directly.

This means that there are no conversion losses, which are typical when charging and discharging batteries, especially when the electricity is generated by a diesel generator, which itself only achieves an efficiency of 40 per cent.

To test their system in practice, Brauner, Sichau and other partners, including the SPW propeller foundry, Peter Frisch and the Cuxhaven boat and shipyard, converted a 50-year-old LM 23. The Bukh diesel engine was removed along with the gearbox, shaft, tank and starter battery. It has now been replaced by a whisper-quiet 6-kilowatt electric motor from Vetus.

It is powered by an H2 fuel cell that delivers 5 kilowatts of continuous current. The cell will later be located in the former oilskin locker on the companionway of the motor glider. It will be delivered in the next few weeks. It is supplied from a pressurised cylinder filled with up to 200 bar in the forecastle, which provides a range of a good 60 nautical miles and can be replaced in a few simple steps.

The LM also has a compact methanol fuel cell (Efoy Pro 2800). It serves as a backup and otherwise charges the consumer battery. With 125 watts of power, it can generate 250 ampere hours per day.

Dispensing with lithium batteries ensures a superior CO2 balance

The battery bank is comparatively simple. In addition to a 12-volt service battery, the "H2 Innovation" has just four AGM batteries from Victron, each with 240 ampere hours - less than one kilowatt for the drive. This is precisely what makes the decisive difference. For a boat of this size and weight, 20 to 25 kilowatt hours of LiFePo batteries would be the norm. However, these would have a significant impact on the CO2 and other environmental footprint.

To compensate for the energy required for production alone, the LM would have to log 200 to 300 engine hours per year for at least five years - more than most owner-operated boats ever manage.

If we assume the current electricity mix in Germany, which still contains significant amounts of CO2 from energy sources such as gas and coal, the motorised sailboat would have to cover more than 400 operating hours per year to become sustainably green in a reasonable amount of time. On average, however, privately owned boats barely achieve half that.

This means that an electric drive for battery-powered yachts will never be climate-neutral, because the capacity of the electricity storage system will already dwindle significantly before the ecological break-even point is even reached.

Prototype is part of a complete solution

What's more, the infrastructure in the harbours is not nearly prepared to provide several yachts per jetty with sufficient charging current to recharge large amounts of electricity overnight. This is another reason why the "H2 Innovation" concept makes far more sense than the e-drives from series production yards, which have hardly been in demand to date anyway.

The Innovation Centre in Nordenham has not only developed the prototype of a fuel cell drive, but has also gone one step further: Dieter Sichau has also installed a solar-powered electrolyser in the halls at Werftstraße 1, where fuselage panels for Airbus are also tested. The INP therefore produces the hydrogen for the LM 23 on its own.

The technology, which can be seen behind Plexiglas, can be "scaled as required", says the managing director. It can supply the fuel for the cells practically anywhere as required. The INP even produces the ultrapure water for the process on site, and will soon also be producing methanol for the Efoy fuel cell.

Supplied with electricity from photovoltaics on the roof, the system requires neither transformer stations nor power lines as thick as an arm to supply an entire marina. A 20-foot container is sufficient for an electrolysis station. "You simply have to think and solve mobility holistically," says Dieter Sichau. "Then it will work!"

Together with Ralf Brauner, he now wants to develop the technology further and bring the concept close to series production. After all, such a drive concept will only become attractive when it is closer in price to the established diesel engine. This is not yet the case at the prototype stage.

The H2 fuel cell planned for the LM 23 alone currently significantly exceeds the cost of a complete diesel unit. However, Sichau is certain that the technology can become competitive with higher quantities, especially as the costs for a large battery pack are eliminated. These are a considerable burden on conventional e-drive concepts based on LiFePo (surcharge for 45-foot yachts compared to diesel currently around or over 100,000 euros).

"I actually wanted to cut back a bit," says the enterprising manager, who has already managed the German business for Siemens Gamesa and worked in responsible positions for other major players in the energy market. This will probably not be the case for the time being.

For more information on the fuel cell drive and electrolysis, click here!