Electric ASV awarded

The world’s first fully electric air supported vessel (ASV), the ‘BB Green’, by Green City Ferries, has been awarded the ‘electric and hybrid propulsion system of the year’ at the Electric & Hybrid Marine World Expo Conference 2017 in the Netherlands.

The fourth annual Electric & Hybrid Marine Awards took place in Amsterdam where a judging panel made up of leading international marine journalists, industry experts and academics, honoured the world’s finest engineers and innovative products in the electric and hybrid marine arena.

The BB Green is used as a commuter ferry for up to 99 passengers on the inland waterways around Stockholm. Swedish-based Green City Ferries has a philosophy of producing fast, electronically-driven, quiet vessels with zero emissions to provide environmentally-friendly transport. The company is dedicated to preserving marine eco-systems and enhancing air quality for passengers.

“BB Green is not only the electric ferry of the year but also represents the future – and I think we should all be looking to see how we can make transportation better for the future,” says Hans Thornell, chief executive officer of Green City Ferries.

The design of the 25-ton ASV, created by Effect Ships International, has a hull that sits on a cushion of air, provided by a fan, to reduce friction by 40 per cent when compared to a conventional vessel. A dual inlet, single outlet centrifugal fan is located in the bow of the BB Green, and the pressurized air it produces enables the vessel to reach higher speeds and use 40 per cent less fuel than traditional propulsion methods. It is the world’s fastest ASV – and the first electric vessel of its kind to be used as a passenger ferry – the BB Green has a top speed of 30 knots (56 kmh) and is capable of high-speed operation for 30 minutes.

A 200 kWh lithium titanate energy storage system in the prototype powers two electric motors. In the context of every day operation, the ambition is to use a 500 kW battery, providing a range of 26km; the vessel can be recharged in less than 20 minutes. The battery system has a multi-string and multi-pack configuration that allows for an increase or decrease in capacity, easily, as required and provides full redundancy; and this also allows for customization in any marine environment. In addition, the battery is connected to an online cloud where data is monitored, thereby enabling the optimization of its operation.

“With this battery storage system, we set out to create an adaptable power source to show other operators that they could have a vessel like ours that is tailor-made to their own purposes. It is a vertically integrated system solution.”

The performance of the BB Green is amplified by two propulsion pods by Volvo Penta.

“We have used cutting-edge design and technology, and Volvo Penta’s pods are an important part of the BB Green design,” adds Thornell. “Our vessel is a forward-thinking option for commuting on city waterways as it is high speed and emission-free.”

Volvo Penta has been happy to participate in the BB Green project, to test the viability of fully electric drivelines. The company has supplied its state-of-the art pod propulsion technology and Electronic Vessel Control (EVC) System to support the prototype vessel. The pods and EVC system are connected to the electric motors and provide both performance data and practical knowledge of how the fully electric passenger ferry can operate.

“We are encouraged by the recognition that the BB Green vessel has received,” says Johan Wästeräng, head of Volvo Penta’s marine product management. “Our current focus is to validate the customer benefits that existing and future technologies provide, which is why we see the value in participating in projects like BB Green.”

He adds: “We see hybrid technology as a step forward in the marine industry, and we are continually looking at new ways in which we can provide new innovative solutions. To be part of a project that has won a sought-after international accolade, shows the investment we are making for the future of transport.”