This article is part of our special report Navigating the road ahead for battery tech.
The world’s largest all-electric ferry completed 10 months of trials last week, as the EU-funded project revealed that battery-powered boats will save operators money compared to their diesel counterparts during their decades of service.
Ellen is a 60 metre-long car and passenger ferry, plying a route between two Danish islands in the Baltic Sea. It is most notable for being exclusively powered by 4.3 megawatts of battery power.
In August 2019, Ellen – which received funding from the EU’s Horizon 2020 research programme – began operating a 40km return-trip route. High-performance chargers top up the battery between sailings, so passengers do not need to wait long to depart.
After nearly a year of service, the e-ferry’s operators concluded that the entire system has an energy efficiency rating of 85%, nearly twice that of diesel boats. That success has a direct impact on how much it costs to run the vessel.
“Perhaps most important of all for the dissemination of e-technology, pure electricity is simply the cheapest solution now,” the Ellen project team said in a statement, adding that although the upfront costs are still high, operating costs are much lower.
According to their calculations, an e-ferry that cost just over €15 million to put in the water will reach financial parity with an older diesel vessel in its fourth year of service and achieve the same feat versus a new boat in its fifth year.
“Depending on the conditions, technical and regulatory, that apply to the route”, an e-ferry will be the most economical option after a maximum of eight years, Ellen’s operators said, adding that “significant savings” can be made given that ferries typically have a shelf life of 30 years.
Over the 10 months of voyages, passengers were asked to complete a survey about their experience. Almost all were very happy with the quieter trip and lack of diesel fumes on deck due to lack of engine. None voiced concerns at being on an electric boat at sea.
It is not just financial savings that can be made by the vessel: the e-ferry can also curb emissions by 2,250 tonnes of CO2 every year, if the power used to charge the battery is 100% renewable energy.
Denmark’s typical energy mix, which also includes decreasing amounts of coal and gas, would limit the vessel’s green impact to 2,010 tonnes.
The Scandinavian country is moving quickly on cleaning up its energy generating systems. Last week, its government agreed on a plan to cut emissions by 70% by 2030, which will include building wind-focused ‘energy islands’.
It also foresees a carbon tax, which will be negotiated later this year, and more charging infrastructure for electric vehicles.
Governments will have to start thinking in earnest about how to reduce carbon emissions from the shipping sector, which in the EU makes up about 3.7% of total CO2 output, if the bloc is to honour its commitments to the Paris Agreement on climate change.
Work is ongoing to include the sector in the EU’s carbon market for the very first time, which would charge shippers for pollution permits. MEPs on the environment committee vote on 25 June on a draft report aimed at accelerating that legislative rollout.
What goes for boats is also true for automobiles. Upfront costs for electric cars are still higher than those for equivalent petrol and diesel versions but the point at which the two powertrains will reach price parity is rapidly approaching.
Battery costs are decreasing at a stable pace, due to economies of scale and advancements in technology. Mobility experts predict that once power packs cost $100 per kilowatt-hour, they will be on the same footing as the internal combustion engine.
Bloomberg New Energy Finance estimates that parity will be achieved in 2024, although new multi-billion-euro aid packages unveiled by European governments, which include electric vehicle and battery-based objectives, could accelerate that timeframe.
The parity-point is seen by many car market analysts as a tipping point after which new sales of electric vehicles will escalate quickly and then only be limited by factors like access to charging infrastructure.
According to the e-ferry project operators, any emissions created during the manufacturing process of the vessel’s battery would be offset in just three months, again due to the carbon-intensity of Denmark’s electricity grid.
Calculating an electric vehicle’s green credentials is more complex given that cars are not always driven on a fixed route, unlike a ship, and Europe’s patchwork of energy mixes is so varied.
For example, driving an EV in Poland will emit 174g of CO2 per kilometre because much of the electricity behind the plug is generated from polluting coal. In Sweden, however, it is just 51g, according to data supplied by mobility group Transport & Environment.
Despite the discrepancies, the full picture shows that electric cars emit on average three times less CO2 than diesel and petrol equivalents.
Producing an accurate life-cycle assessment of a vehicle is a difficult task. US carmaker Tesla said in its recent report for 2019 that a number of glaring omissions are still made by some analysts that look to demonstrate the impact of its cars vs the combustion engine.
They include the use of emissions data from a now-outdated testing procedure that does not reflect real-world driving standards, inaccurate cost statistics about battery cells and the assumption that an electric battery will have to be replaced during the car’s lifetime.
“Tesla’s battery packs are designed to outlast the car. We estimate that a vehicle gets scrapped after 200,000 miles in the US and 130,000 miles in Europe. Creating a battery that could last for 1,000,000 miles would drastically reduce emissions per vehicle produced,” the report says.
That objective is not as outlandish as it may seem, as Chinese firm CATL – which supplies both Tesla and Volkswagen – announced in early June it had engineered a power pack with those credentials and that it would only cost 10% more than a standard EV battery.
It is not clear yet whether CATL has developed the battery, which it claims will last 16 years, in collaboration with Tesla or if it is a separate project. The company is yet to reveal if any orders have been placed by other carmakers.
[Edited by Zoran Radosavljevic]