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Bodensee-Schiffsbetriebe GmbH

Charting a Greener Course: Christoph Witte’s Vision for Bodensee-Schiffsbetriebe

We engage in an insightful conversation with Christoph Witte, Managing Director of Bodensee-Schiffsbetriebe GmbH, as he shares his innovative approach to transforming ferry operations on Lake Constance. With a strong commitment to environmental stewardship, Christoph discusses the strategic decision-making behind adopting fully electric ferries, the challenges of implementing sustainable energy solutions, and the vision for decarbonising the entire fleet. Discover how Bodensee-Schiffsbetriebe is setting a pioneering example in the decarbonisation of German inland navigation, aligning with the broader goals of sustainability and technological advancement.


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Strategic Innovation: Could you explain the decision-making process behind choosing fully electric ferries for short routes, such as the MS ‘Insel Mainau’ operation?


Almost exactly five years ago, the city of Konstanz declared a climate emergency and subsequently decided to become carbon neutral by 2035. As a municipal company, we were naturally among the first to be called upon to implement this initiative, and we were happy to do so.


The first Corona season gave us a lot of time to think about fleet development. Normally, we replace old vessels with new ones of a similar size. However, it was clear at the time that there were no alternative propulsion solutions, especially for the large vessels, that we could invest in sustainably. To avoid losing more time on the path to decarbonisation, we considered where we could use a fully electric ship sustainably, also from an investment point of view. The result is the design of the MS INSEL MAINAU, which sails between Uhldingen, the island of Mainau, and the town of Meersburg.


However, we have never lost sight of the bigger picture – the decarbonisation of the entire fleet – and have continued to refine our concepts in parallel.


True to our motto: Think big, start somewhere!


Operational Efficiency: How does the operational profile of 15-minute crossings with quick turnaround times enhance the efficiency and attractiveness of your ferry services?


First and foremost, electric drives are significantly more effective, with much lower losses, than combustion engines. The efficiency of a modern all-electric drive system is around three times higher than that of a conventional diesel drive. Additionally, we had the ship’s lines optimised for our application using computational fluid design (CFD) to reduce the ship’s resistance and required propulsion power. The MS INSEL MAINAU can transport up to 300 passengers with just 2x60kW drive power.


As the distance to be travelled is relatively short, we decided to travel more slowly than before. The cruising speed has been reduced from 23 km/h to 15 km/h. This was another major gain in efficiency. Our passengers now have a wonderful little cruise: gliding across Lake Constance in complete peace and quiet, without any emissions. The new passenger compartments are designed to enhance this experience.


Charging Infrastructure: What were the key factors in setting up the 3MW transformer stations and quick-charging batteries for the e-LODI ferries?


The good results with the MS INSEL MAINAU, and further developments in battery technologies, motivated us to consider the electrification of other lines. The ferry operated by Stadtwerke Konstanz GmbH has a 15-minute crossing time, with an equivalent time for charging. Meanwhile, the fast-charging capability has developed to a point where it is possible to recharge the energy required for the crossing during cargo handling. Together with the required drive power, this necessitates a charging station capable of providing 3MW.

Sustainable Energy Solutions: Can you discuss the integration of the E-TABOR for Stadtwerke Konstanz GmbH system with solar power installations at gateways to Constance and how this contributes to the ferries’ energy needs?


The project would become really attractive if we were to cover the entire forecourt, which is already sealed with asphalt, with solar cells. These areas are so large that at peak times, i.e., under optimal conditions, they would cover the energy requirements of the ferries to be loaded. Even in less ideal conditions, a considerable proportion of the energy could still be generated on-site. It would also serve as a great new landmark for the city of Constance, which was the first to declare a climate emergency: The city’s gateway as a kind of solar tunnel via which I can enter the city by ferry.


We expect to produce 20-30% of the energy we need ourselves. We would still need to draw most of our energy from the grid. But since the entire country wants to become climate-neutral, energy production will also have to move towards renewable alternatives. Within our sphere of influence, we have done everything we can to turn the ferries climate-neutral.


Environmental Impact: What impact do you foresee the solar power installations and the battery system having on Bodensee-Schiffsbetriebe’s carbon footprint?


For Bodensee-Schiffsbetriebe (BSB), self-produced solar power holds secondary importance. BSB mainly operates on long routes with long harbour times and large ships. Additionally, we have a significant number of traditional ships that need to be preserved, as it is precisely because of them that guests come to the beautiful Lake Constance. The energy density of batteries is not sufficient in this context, and we have been investigating solutions involving hydrogen or methanol, which is a hydrogen carrier, for some time. Methanol, in particular, seems very interesting to us, and initial conversion concepts have already been developed. We are, of course, talking about green methanol here.


System Architecture Challenges: What are the biggest technical or logistical challenges you’ve faced while implementing the SYSTEM ARCHITECTURE E-TABOR for your ferries?


The biggest challenge has been and continues to be the charging infrastructure. We have to transfer 3MW of power in a short time, which cannot be done with a simple plug system. Therefore, we need to develop a special and certifiable solution for this. While the on-board systems are demanding, there are now standards that we can build on, making it somewhat easier to manage these complexities.

Policy and Economic Support: How critical is economic and political support for transforming Lake Constance into a model region for climate-neutral shipping?


This support is extremely important for us; we need it, it’s as simple as that. No shipping company is in a position to bear these high costs itself. Incentives in the form of support programs must be created. Currently, the funding rate for ship conversions is too low. For the MS INSEL MAINAU, it was just 9% of the total costs, for which we are really grateful, but that will not be enough for the larger projects. The funding rate for electric buses in Germany was once 80%, and the CO2 savings here are significantly lower. If we were to start talking about the costs of decarbonisation, i.e., where to get the CO2 reduced with as little money as possible, then we would very quickly end up with shipping and invest in a greener future here.


Long-Distance Decarbonisation: Could you elaborate on the methanol concept for decarbonising the entire BSB fleet and the timeline for its implementation?


Yes, methanol is the concept for our large vessels, while the smaller ones will be supplemented with fully electric ships. The goal is to decarbonise the entire fleet by 2035.

Vision for Future: What are your long-term goals for BSB in terms of technological advancements and fleet expansion?


We are not currently thinking about expanding the fleet, but are focused on how we can decarbonise the existing fleet and use it more effectively. We are always keeping our eyes open for new technological developments that we could leverage. However, we believe that development will move strongly in the direction of methanol drives, as major global players are already relying on this technology. What is primarily still missing is the necessary infrastructure.


Leadership Philosophy: What drives your passion for leading environmentally friendly transport solutions at Bodensee-Schiffsbetriebe GmbH?


Bodensee-Schiffsbetriebe GmbH operates shipping in Germany’s largest drinking water reservoir. Large parts of the shore regions are under nature conservation protection. BSB has voluntarily subjected itself to environmental certification for years, and the regulations for shipping have been leading in Germany for many years in terms of environmental protection. We have long been committed to these values, having put the first EUV-certified ship in Germany into operation on Lake Constance, and built a gas ferry that can be operated with BioLNG. Now, we want to play a pioneering role in the decarbonisation of German inland navigation. What could be better suited for this than the Lake Constance region? We want to be a role model and motivator for other shipping companies.

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TECHNOLOG provides specialised maritime consultancy and engineering services, focusing on innovative ship design, marine consulting, and advanced maritime technology. Their expertise covers concept development, project implementation, conversion, and retrofitting of ships, ensuring high efficiency and compliance with industry standards. With over 30 years of experience, TECHNOLOG supports global clients with customized solutions for various maritime needs, from new builds to modifications.