E-Ferry – Fully electric into a sustainable future?
The transport sector accounts for almost a quarter of all greenhouse gas emissionsin Europe and is the only sector in which emissions have even increased in recent years(European Environment Agency 2021). This development endangers the EU Green Deal and the goal of climate neutrality. A climate-neutral transport sector may sound like a utopia at first, but the International Maritime Organization (IMO) is still setting it as a goal. With the decision of April 2018, the 174 IMOmember states have committed themselvesto at least halving the CO2 emissions of ships by 2050 compared to 2008 (IMO 2018). This article presents the exciting Horizon 2020 project “E-Ferry” and explains how an all-electric ferry gives hope to achieve the ambitious UN goals in the transport sector.
In fact, in 2015, the first all-electric ferry called "Ampere" sailed on the Sognefjord between Lavik and Oppedal in Norway. To this day, it coversthe distance of 6 km 34 times a day. Yet even the Ampere is only half as heavy as a conventional car ferry and causes only 5 percent of CO2 emissions in comparison (Infineon Technologies AG 2021). The E-Ferry project delivered similar exciting results: The passenger and carferry has been in operation in Denmark since August 2019 on the route Søby-Fynshav (at the operator AEROE-Ferries) and has already covered the distance of 22 nautical miles – about 40 km – 1000 times in the first 10 months of probationary period.
The project
The project, which was launched in June 2015, was intended to design, build and demonstrate a ferry that is fully electric, i.e., "green", and thus emits neither pollutants nor CO2. This should promote energy-efficient, greenhouse gas and air pollution-free transport on water for island communities, coastal areas and inland waterways in Europe and beyond. The specifically formulated goal was to design an emission-free ferry of medium size for passengers and cars, trucks and Cargo1 in large-scale operation, which can operate at greater distances than before, namely more than five nautical miles. Given this goal, the project outcome is more than encouraging, as the E-Ferry surpasses previous capabilities of similar efforts aimed at medium-range connections.
The E-Ferry
Figure 1: The E-ferry prototype "Ellen" (Source: www.E-Ferryproject.eu/Output-Material)
The E-Ferry with a total length of 59.40m offers space for 31 cars or five trucks on an open deck, as well as 198 passengers in summer (147 passengers fit in winter). When fully loaded, the ferry has a draught of 2.50 m, which is comparatively low to ferries of similar size and capacity. One of the ferries the E-Ferry can be compared with, is the LMG-50 ship type with diesel-electric propulsion from the Danish manufacturer LMG Marin AS. This comparison provides helpful data on the environmental, economic, and energy specifications of the E-Ferry for evaluation purposes. The LMG-50 has similar dimensions and is a viable alternative, as it meets the requirements for the route in question. The LMG-50 has a draught of 3.30 m, which is 0.80 m more than the E-Ferry. In view of the increasing challenges in terms of fluctuating water depth due to climate change, this might be an advantage of the E-Ferry. Furthermore, the E-Ferry is comparably light with its lightweight of 746 tons. This allows an average speed of 13.5 knots with a draught of 2.30 m, as well as a top speed of 14.2 knots. For comparison: The LMG-50 only has an average of 11 knots and a maximum of 12 knots. The E-Ferry requires a total output of at least 1000 KW (Kortsari et al. 2020).
One of the partners of the IW-net project the REWWay team is currently part of, was able to take a ride on “Ellen”. And that's how it feels, according to Herfried Leitner of Transport Trades Services GmbH, to be on the E-Ferry: "You don't hear anything on board at all. It's a terrific feeling and very fascinating." His experience attests to the necessity of including noise as another cost to society in an overall assessment. It is not surprising that after this successful 9-month construction of the first E-Ferry "Ellen", more are to follow. The ambitious goal is to put about ten more E-Ferries into operation in Europe and worldwide every year. In 2021 – 2 years after the end of the project – in the best case, more than 20 E-Ferries based on the model of "Ellen" should have already been put into operation. For sure, more electric ferries were built on base of this successful project, for example the MF Grotte in Denmark or the Basto Electric in Norway, a superlative electric ferry in terms of size. Overall, there might be already 15 electric ferries in operation in Skandinavia.
The battery
What defines an E-Ferry is clearly its battery. Since the success of the project depended to a large extent on it, in the following part, the battery and its specifications are examined in more detail. The E-Ferry is equipped with a total of 840 battery modules, with a total capacity of 4.3 megawatt hours (MWh). The battery is fully charged at night and then during breaks of 25 to 45min in the ports. The effective charging time is reduced by five minutes due to the coupling and decoupling processes. In each of these breaks, the battery is charged with between 1100 and 1700 kWh, depending on the state-of-charge, i.e. the percentage of charge, at the time of the start of charging and the charging time itself (Kortsari et al. 2020). The charging power is an impressive 4 MW. An electric car can currently be charged with a standard output of 150 up to a maximum of 350 kW (ADAC 2021). Moreover, the charging process is fully automatic: No human interference is required for docking and undocking, even in rough weather such as wind and waves. On average, the E-Ferry consumes 1600 kWh per round trip, which is significantly less than the consumption of the compared diesel-electric ship. There is a difference of 848.4 kWh in total consumption per day. Due to the fact that only a capacity of 1100 to 1300 kWh is achieved with the charging power in the charging time, the charge level gradually decreases over the day and in the end amounts to 30% of the nominal capacity of 4.3 MWh (1.29 MWh = 1290 kWh). Minimum requirement is 2x400 kWh residual charge for emergencies (Kortsari et al. 2020). This emergency reserve of energy makes an emergency (diesel) generator obsolete, which was intended by the design team. As soon as the energy level is exceeded, an alarm notifies the crew and the engine power is automatically reduced to conserve remaining energy (Kortsari et al. 2020). Moreover, the energy available that is provided as information for the crew via the Power Management System on the bridge is a calculated value, based – among other things – on a cyclic counter for estimating the State-of-Health of the batteries. If the available energy is not sufficient for the upcoming trip, whose energy consumption is calculated based on the data of completed trips, the E-Ferry engine will not start.
Project conclusion
In terms of performance, the E-Ferry prototype has met the originally defined requirements with some minor deviations. Although the e-ferry is about 5% heavier than originally planned, the design changes to the battery and charging system in particular have ensured that average energy consumption has not been measurably affected. But not only technically the E-Ferry can compete with conventional ferries, also the economic evaluation has shown that the E-Ferry prototype represents a real commercial alternative from a purely economic point of view. Despite higher construction and innovation costs and the fact that the battery pack may need to be replaced twice during the lifetime of the vessel, this cost difference is amortized after 5-8 years of operation. This can be explained by the significantly lower operating costs, especially for energy/fuel, for all-electric ships. Battery systems in particular account for a large share of the initial investment costs of the E-Ferry prototype, but due to the steadily decreasing costs of €/kWh even for maritime uses, the prospects for fully electric ships in the future are even better. In addition, there are possible charges for less climate-friendly modes of transport, which the EU could decide on in the future. Compared to the best technological alternative on the market, the E-Ferry saves 2,520 tons of CO2 if the electricity used is fed by renewable energies. The resulting CO2 emissions from battery production (215-430 tons) correspond approximately to the amount generated by a 3-month operation of a diesel-electric ferry and are therefore quickly compensated (Kortsari et al. 2020). Accordingly, this project marks another milestone on the road to the green mobility of the future. Especially since between 701 and 671 ferries were in operation in the EU from 2006 to 2012, for which an E-ferry model like Ellen could be an economically relevant alternative (Brambilla and Martino 2016).
References:
ADAC (2021): Elektroauto Schnellladung: Ladeleistung im Vergleich. Available online at https://www.adac.de/rund-ums-fahrzeug/tests/elektromobilitaet/schnellladen-langstrecke-ladekurven/, updated on 9/7/2021, checked on 2/21/2022.
European Environment Agency (2021): Greenhouse gas emissions from transport in Europe. Available online at https://www.eea.europa.eu/ims/greenhouse-gas-emissions-from-transport, updated on 11/18/2021, checked on 12/27/2021.
IMO (2018): Initial IMO Strategy on reduction of GHG [greenhouse gas] emissions from ships. MEPC 72/17/Add.1. Available online at https://wwwcdn.imo.org/localresources/en/OurWork/Environment/Documents/ResolutionMEPC.304(72)_E.pdf, checked on 2/21/2022.
Infineon Technologies AG (2021): Elektro-Schiffe: die Zukunft der Schifffahrt - Infineon Technologies. Infineon Technologies AG. Available online at https://www.infineon.com/cms/de/discoveries/elektrische-schiffe/, updated on 7/1/2021, checked on 2/21/2022.
Kortsari, Annie; Mitropoulos, Lambros; Heinemann, Trine; Mikkelsen, Henrik Hagbarth (2020): E-Ferry Project. Prototype and full-scale demonstration of next-generation 100% electrically powered ferry for passengers and vehicles. Evaluation Report of the E-Ferry, p. 139.
Marco Brambilla, Angelo Martino (2016): Research for TRAN Committee - The EU Maritime Transport System: Focus on Ferries. Available online at https://www.europarl.europa.eu/RegData/etudes/STUD/2016/573423/IPOL_STU(2016)573423_EN.pdf, checked on 3/21/2022.
