A new generation of increasingly robust switchboards is helping save time, money and, perhaps surprisingly, emissions
The last pieces of the mechanical jigsaw that will power Brittany Ferries’ latest ro-pax, Honfleur, were dropped into place in mid-December.
They included the electric propulsion motors that will play a vital role in the vessel’s gas-electric propulsion system, each of them driving a shaft line as its speed and torque is adjusted continuously while the ship is sailing or manoeuvring.
When the propellers are turning at reduced speeds – for instance, during slow crossings or in port – their vibrations will be hardly detectable. As a bonus, fuel consumption will be lower on the LNG-powered 42,400 gwt ferry, which has an overall length of 187 m and a beam of 31 m and can accommodate 1,800 passengers; it has a cargo capacity of 2,200 lane metres, plus a dedicated 300-space car deck.
A flagship project for Brittany Ferries, Honfleur is also a feather in the cap of Kongsberg Maritime, which won the ‘full picture’ contract to supply much of the advanced vessel’s technology – shaft generators, switchboards, automation systems, emergency shutdown, rudder control and navigation systems, among others.
Crucially, all these systems depend on the smooth functioning of the switchboards, also supplied by Kongsberg Maritime and partner Schneider Electric.
Although switchboards are not the first items of equipment that come to mind in the low-emission era, they play an increasingly important role in regulating a ship’s power supply and consequently its energy efficiency. The fundamental job of the switchboard is to distribute electricity to all those many services that maintain operations all over the ship, from onboard machinery to navigational tools and fire safety. The more efficiently the power is passed around the vessel, the less waste of power. In this way, switchboards have become powerful tools for controlling energy consumption on board increasingly energy-efficient ships.
Switchboards are playing a key role in the transition to hybrid and all-electric technology. When Norwegian ferry group Vidar Hop Skyssbater group takes delivery of a new battery-powered car ferry later this year, the hub of the operation will be the switchboards that manage the energy. This latest generation of switchboards is designed to marry up with electric or hybrid power, in this case lithium-ion batteries from Corvus Energy that are designed for lightweight applications. A leading manufacturer of energy storage systems for ships, the company says its Dolphin batteries are aimed at high-speed vessels or those that need to recharge batteries quickly and often, like short-haul ferries.
Distributing power between the batteries and other shipboard functions will be two switchboards of 440 volts and one of 230 volts, all supplied by Norway’s Clean Marine Switchboards.
A new-era vessel, the ferry is ultra-lightweight, weighing in at 146 gwt tonnes and boasting a composite hull and structure. Just 27-m long, with a beam of 9.7-m, the ship has a maximum capacity of 10 cars and will ply a route between the coastal towns of Barmen, situated in the most western part of Norway, and Barmsund just nine minutes away.
Clean Marine also supplied the switchboards for Fjord1’s new electric ferry, Hadarøy. Bristling with digital technology, the ferry features 1000-volt DC multidrive switchboards, 230-volt AC main switchboards, 440-230-volt shore connection cabinets, a drencher pump cabinet and various distribution cabinets.
If nothing else, the array of switchboards proves how fundamental they are to battery-powered, digitally based vessels.
The Hadarøy will sail Norway’s Sulafjord, which is rapidly becoming a playground for shipping with record low energy consumption. Courtesy of a NOK100M [US$10.43M] grant from the Norwegian government, marine scientists extract information about wind, current, temperature, wave height and length, all supplied from an array of measurement masts and buoys located at strategic points in the Sulafjord.
As the ferry’s builder, Havyard notes: “Norwegian researchers have not previously had this data, that provides a unique insight into the fjord.” The shipbuilder absorbs all this information, from what is a living test-tank, and integrates it into digital models.
“In this way we have managed to develop ferries with extremely low energy consumption using a battery system that is not only designed for fair weather, but that also enables fully-electric operation in rough weather,” explains Havyard’s r&d manager Kristian Steinsvik.
Although electric propulsion depends on a variety of technologies, switchboards sit at the heart of it, distributing the required power with pinpoint precision. The Hadarøy is so energy-efficient that it requires the equivalent in power of just eight or nine medium-sized electric cars to transport 120 cars across the fjord.
Start-up leads the way
Clean Marine Switchboards, founded in 2017, enters 2020 with a heavy backlog of orders that include a dredger in Brazil, three windfarm supply vessels that each require up to 690-volt switchboards, and a large catamaran. These follow six contracts completed in 2019 for a variety of ships built or retrofitted in Norway, Spain and Belgium.
It is a feather in the company’s cap that the Ulstein Verft-built hybrid Color Hybrid ferry boasts a full complement of five of Clean Marine’s switchboards, two emergency ones of 690 volts and 230 volts, a main one of 230 volts, plus a 690-volt heating switchboard and a test switchboard.
Why the demand for this fledgling supplier? According to its website, it comes down to bespoke solutions dedicated exclusively to the marine market. “[We focus] on a compact design and innovative high-redundancy solutions,” it says.
Clean Marine claims its switchboards are 40-60% smaller than traditional designs and in terms of the all-important redundancy, its switchboards have three air circuit breakers per section (air circuit breakers are mainly used for protection of power units where there are possibilities of fire or explosions) and up to six moulded case circuit breakers – or MCCBs – per section. Finally, the software for the switchboards is designed to keep pace with what the scientists are doing in the labs because it is updated online.
And anticipating an electrical future for the global fleet, from the outset Clean Marine has developed close working relationships with battery suppliers, so its switchboards can be seamlessly integrated with hybrid propulsion systems.
With switchboards being essential for dynamic positioning (DP), Clean Marine also equipped Acta Marine’s latest service operational vessel. Designed for the offshore wind industry, a fast-growing opportunity for these work vessels, the Ulstein Verft-built Acta Centaurus stays in the desired zone by virtue of two main switchboards. There is also an emergency switchboard of 690-230 volts, the customary shore connection cabinet and fan motor starter boxes.
With demand on the increase for all-electric DP vessels like Acta Centaurs, high-performing switchboards become integral to the design. “The ‘all-electric ship’ approach is the only one that permits – in an easy and efficient way – complete and precise position control under all relevant marine environment solutions,” states Kongsberg Marine.
A switchboard is only as good as the power that supplies it. And here ABB’s latest marine power system tackles reliability head-on. It uses Emax2 circuit-breakers linked to the ethernet. “We use the built-in sensing and intelligence of Emax2 to detect faults and isolate them more effectively,” ABB explains.
The Ekip ethernet link can, says the power giant, locate a fault and isolate it in less than a tenth of a second, fast enough to prevent the vessel straying out of its operational zone. “That is due to the precision of ABB’s node logic and the directional protection that the Emax2 circuit breakers provide,” the company says.
The technical explanation for this rapid-response system is “embedded logic zone discrimination” that protects against over-currents. If the circuit breaker sees a fault current entering the node without the other breakers registering its departure, it means the fault clearly still lies within the node. Within a split second the breaker opens and isolates the fault, as though it were a dangerous virus. When the rogue current exits the node, the breaker sends a blocking signal to the other breakers in the system.
ABB says the system makes for much simpler cabling that cuts commissioning time by about 6%.
The cable guys
The digital revolution has created a cabling problem. As the number of digitised systems proliferates onboard ships, so do the number of cables that run to switchboards and wherever else they are required. “The greater number of digital solutions you have, the more cables you need,” explains Ola Staverøkk, head of sales and marketing at Norway’s Elpro.
Until recently, this cabling threatened to run out of control, but STI Marine may have achieved a breakthrough. The company’s brainwave, EZ-Path, is a seemingly obvious solution; a transit system that can accommodate as many cables – and types of cables – as the ship might need. When National Geographic Endurance, the cruise ship built by Ulstein Verft for Lindblad Expeditions, sets sail on its maiden voyage in April, it will have about 4,000-6,000 m of cable.
“Cables that run through EZ-Path are often connected to switchboards,” says STI Marine’s regional manager for Europe Ruben Wansink. “We also see a lot of applications on fire barriers that connect to server rooms, safety control centres, the bridge and other places.”
In fact, the fire-resistant systems are installed all over the ship. “I believe on National Geographic Endurance that more than 100 EZ-Path devices were installed, with each having a capacity of 70-480 cables per transit,” says Mr Wansink.
And because the transits hold type approvals and A60 classification from DNV GL, installers don’t have to pack cables for fireproofing, as is normally required. Considerable savings in time and costs are claimed for the system.
According to Ulstein Electric chief production officer Atle Moldskred, the arrangement greatly simplifies cabling systems. “EZ-Path is completely different,” he explains. “The [cable] transit is mounted and then you simply pull the cable through.”
The simplicity of the system is attracting buyers. Not only will EZ-Path be installed on a sister ship, National Geographic Resolution, now under construction, the transits are in service on Color Line’s new hybrid ferry, several Hurtigruten ships, a Prince Cruise newbuild and many other cruise ships.