Boluda Towage Europe has reduced the environmental footprint of its tugboat fleet by investing in hybrid propulsion and complying with IMO Tier III emissions requirements
Boluda Towage Europe has made considerable investments in reducing emissions from harbour tugs to cut pollution in ports.
It was one of the first to operate harbour tugs with hybrid propulsion, starting in 2012 with Rotortug RT Adriaan (now named VB Kracht), followed by two more hybrid propulsion Rotortugs in 2015.
This year, Boluda retrofitted tug enginerooms with propulsion to meet IMO Tier III emissions requirements and is introducing tug newbuildings with this compliance. Two of these tugs, VB Bolero and VB Rumba, are already in operation. Rotortugs VB Samba and VB Flandes are coming later this year after they are built to an ART 80-32 design.
Boluda Towage Europe chief executive Geert Vandecappelle explained the benefits and challenges of these investments during Riviera Maritime Media’s How tug operators are preparing for a new era in green marine propulsion webinar. This was held, with sponsorship from Navtek Naval Technologies and LionRock Maritime, on 29 March as part of Riviera’s ITS TUGTECHNOLOGY Webinar Week.
Mr Vandecappelle outlined how his company was a pioneer in deploying hybrid propulsion on tugboats in 2012, then developing and operating a second generation of hybrid propulsion on tugs with the delivery of advanced Rotortugs built to ART 80-32 design, RT Evolution and RT Emotion in 2015.
“The first generation had a lot of issues we needed to put right in the second generation,” said Mr Vandecappelle. This included positioning batteries in one location at the bottom of RT Adriaan, whereas they were split into different rooms on RT Evolution and RT Emotion. When asked what the issue of the battery location was, he replied “the temperature in the area where the batteries were stored was not ideal.”
“All precautions were taken on the second-generation hybrid tugs,” said Mr Vandecappelle. “Extinguishing systems and temperature sensors were installed and there is ambient temperature in the battery room.”
Other technical and financial challenges include the lifetime of batteries, which are only expected to last for 10 years, while tugs can operate for more than 30 years, said Mr Vandecappelle, who wants battery manufacturers to tackle the issue. Also an issue, is reducing the capital expenditure of building tugs with hybrid propulsion.
“Capex is 25% higher than a conventional tug,” said Mr Vandecappelle. “Manufacturers should do research for batteries with longer lifetimes and develop a solution involving less batteries for the same amount of power.”
Other challenges involved training chief engineers and masters to use and maintain hybrid propulsion and for tug dispatchers to plan the mobilisation of these tugs.
He said the benefits of hybrid propulsion include “reduced emissions, lower fuel use and maintenance savings”. ART 80-32 design tugs with hybrid propulsion have 35% less particulate matter, 36% fewer unburnt hydrocarbons, 32% lower NOx and 35% less CO2. This corresponds to 532 kg less particulates, 198 kg unburnt hydrocarbons, 21.6 kg of NOx and 443 kg of CO2 saved per year. Other benefits are lower maintenance costs and less spent on diesel fuel.
“It is also safer for crew as there are less emissions and lower noise,” said Mr Vandecappelle.
IMO Tier III tugs
Boluda has become an innovator in another emissions-reduction technology, by ordering new tugs with IMO Tier III compliance and retrofitting existing tugs. Other owners will need to follow, as all diesel-powered newbuildings with their keels laid after 1 January 2021 will need to comply with IMO Tier III standards if they work in the North Sea and Baltic emission control areas (ECAs).
Inside ECAs, tugs either need to use a selective catalytic reduction (SCR) exhaust gas after-treatment system or another removal technology. SCR systems process exhaust gases, removing NOx through a catalytic reaction using a reductant, usually a urea solution, which emits nitrogen and water.
Boluda took delivery of two new Damen-built Azimuth stern drive (ASD) tugs – VB Bolero and VB Rumba – with SCRs installed for IMO Tier III compliance, for operations in Zeebrugge, Belgium. VB Bolero and VB Rumba were built to an ASD 2813 design with 85 tonnes of bollard pull.
Mr Vandecappelle said there were two more IMO Tier III Rotortugs coming in 2021, ART 80-32 design VB Samba and VB Flandes.
Boluda has also retrofitted tugs Union Koala and Union Panda to IMO Tier III by installing SCRs. Anglo Belgian Corp (ABC) worked with Boluda and Flanders Ship Repair to upgrade propulsion on Union Koala, which had enough available engineroom space for the SCR installation.
“As a long-term partner of the Port of Zeebrugge, we have committed through this project to the port authority’s environmental objectives,” said Mr Vandecappelle. “Through a joint effort, our technical department and ABC have brought this challenging project to a successful conclusion.”
Tugs need sufficient space in the engineroom to accommodate urea storage tanks, dosing pumps, stainless-steel piping, mixing chambers and the SCR reactors.
Mr Vandecappelle said the retrofit project cost around US$400,000 and “it takes around four weeks”. He added this is an “intermediate step towards a better solution” for reducing emissions “because it is proven” technology. He explained “there are no downsides” to operating SCRs, but good planning is involved before the retrofit.
“Good preparation is half the battle,” said Mr Vandecappelle. “It is like putting an elephant in a show box.” Each SCR is around 4 m long, 1 m wide and weighs around 2 tonnes. Another installation challenge is the pipework. “Engineering of the routeing in the engineroom for the new exhaust system is important to avoid clashes with the existing equipment and piping,” he explained.
But these projects yield environmental benefits as NOx emissions are cut by at least 80% per tug. “Emissions reduction on a yearly basis for the entire fleet of six tugs in Zeebrugge, all complying with Tier III, is 353 tonnes,” said Mr Vandecappelle.
In the longer term, tug owners could be expected to cut greenhouse gas emissions from tug fleets, likely leading to the construction of new tugs to renew fleets. “Retrofitting a tug to reduce the CO2 emissions is impossible without major changes,” said Mr Vandecappelle.
“There would need to be an investment from shipowners,” he continued. Because at present, there are “no climate contributions paid by the customer or port authority for the use of these tugs and their ecological footprint.”
Mr Vandecappelle said in the long term, hydrogen could be the best zero-emissions fuel, but it comes with challenges, as do other fuels. “Hydrogen is promising, but is expensive,” he said. “Ammonia is toxic and batteries’ lifecycle is less than the lifecycle of tugs. Methane is a more powerful greenhouse gas than CO2, therefore it is not green.”
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