Tug owners should prepare to invest in green tugs as ports look to cut emissions, according to experts during Riviera’s ’Hybrid and electric tug viability: the future’s bright’ webinar
Panellists for the Wärtsilä-sponsored webinar, part of Riviera Maritime Media’s Tug Technology Webinar Week, were Port of Luleå technical manager John Sundvall, Great Lakes Towing Co president Joseph Starck, Wärtsilä Marine Power director of business development Giulio Tirelli and Damen Shipyards product manager for tugs Erik van Schaik.
Discussing hybrid and all-electric options for tug owners to reduce their environmental footprint and operating costs, panellists tackled the financial and practical challenges and the balancing act between higher capital expenditure for battery-driven tugs and the long-term operational cost savings from lower emissions.
Mr Sundvall provided insight from more than a year of operating the powerful hybrid-propulsion tug, Vilja, a 2019-built ice-breaking tug built by Gondan Shipyard in Spain to a Robert Allan TundRA 3600 design with Wärtsilä integrated power systems.
Mr Sundvall said the reasons for investing in a hybrid tug was to reduce emissions during transits to towage jobs and to use the clean energy available at the quayside.
“A key benefit with our hybrid is low emissions during missions, when we may only need to use one engine,” said Mr Sundvall. Another benefit is the peak shaving function when power loads are uneven as Vilja operates through ice in the Port of Luleå.
Batteries also provide a boost to Vilja’s power, increasing its bollard pull from 90 tonnes to 100 tonnes for heavy towage in ice.
In comparison, Mr Starck explained Great Lake Towage’s strategy for modernising its fleet through a multi-tug newbuilding campaign at its own shipyard in the US.
It is replacing its vintage tugs with hybrid tugs based on Damen’s Stan Tug 1907 ice design. Four of these tugs are completed and the keel of the sixth hull has been laid, said Mr Starck.
“We have two types of hybrid devices from Logan Clutch Corp,” he explained. “FlexaGen replaces a generator with an electric motor driven off-gear, saving fuel and emissions,” Mr Starck said. Logan’s FlexaDrive has two electric motors on the gearbox and means an engine can operate as a generator, or a generator can act as an engine.
“Our tugs can run on the electric motor and on one 99-kW generator set when underway,” Mr Starck said. “We did not want batteries as they are too complicated,” he added.
Mr Tirelli spoke about evaluating higher capital expenditure for hybrid propulsion versus the anticipated cost savings from operations and maintenance. He said owners need to consider the whole integrated propulsion system when calculating requirements and expenditure, and not just start with the battery.
“It is about finding the balance between everyday needs of low power with heavy assist and high bollard pull for just 1% of the time,” said Mr Tirelli. “We need to retain this capacity, but finding the balance is challenging. Hybrid helps find this balance between opex and capex.”
Tug operators have various bollard pull needs in different modes of operation, which means hybrid propulsion needs to be “tuned for the best fuel consumption and least extra capex. There are a lot of possibilities” said Mr Tirelli.
Mr van Schaik took comparative analysis further with his presentation. He evaluated the total cost of ownership of a tug that could be all-electric or with hybrid systems.
“There could be much variation with operating profiles and configurations,” he said. “Everyone is looking to achieve maximum fuel reduction and emissions reductions and minimum rises in costs – and this is what we are trying to achieve,” said Mr van Schaik.
“There is a focus on opex and total cost of ownership, including balancing capex and opex,” he continued. “When looking at lower emissions, the easiest is to use shore power with batteries. Then, total cost of ownership can be equalised between fully electric and hybrid systems over the lifetime.”
Panellists were very persuasive in their argument for investing in hybrid and electric propulsion. Attendees were mainly in agreement to the statement: Hybrid solutions are a good fit for tug operations. When asked to vote on this, 57% strongly agreed and 32% agreed, leaving just 5% disagreeing 1% strongly disagreeing and 5% remaining on the fence.
Attendees were then asked whether they thought there was a market for fully electric tugs. To this question – A growing number of port authorities are aiming to be emissions-free between 2030 and 2050. As a result, there is a market for fully electric (zero-emissions) dedicated harbour tugs – 80% agreed and 20% disagreed.
As ports consider their options for reducing emissions, more are providing shore power with direct electricity outlets on quaysides, known as cold ironing.
Attendees were asked their opinion as to whether this would encourage more investment in electric vessels. They were asked whether they agreed with this statement: Due to the introduction of cold ironing and electric cargo handling equipment, the electric infrastructure in most big modern ports has become suitable for fast charging fully electric tugs. 55% of attendees agreed and 45% disagreed.
In another poll, attendees were asked to vote on which fuel they think most tugs will be running on by 2030. 44% said it would be marine diesel, 16% said alternative fuels, such as hydrogen, ammonia and methanol. Another 12% said LNG, plus another 12% thought it would be heavy fuel oil and blended fuels, but16% thought none of these options.
In one more question, attendees were asked what their biggest focus or concern was when dealing with tug-related developments. Of the respondents, 40% said initial investments, 25% running costs, 21% safety, 9% environmental compliance and 5% none of these options.
You can view this webinar and all of the webinars from Riviera’s Tug Technology Webinar Week, in full, in our webinar library.
And you can sign up to attend our upcoming webinars on our events page.
Webinar panel consisted of (left to right) Damen Shipyards product manager for tugs Erik van Schaik, Wärtsilä Marine Power director of business development Giulio Tirelli, Port of Luleå technical manager John Sundvall and Great Lakes Towing Co president Joseph Starck