Collaboration empowers maritime decarbonization

As a 30-plus year military veteran who spent his career designing, constructing, operating, maintaining and fixing vessels of all types – aircraft carriers to submarines – for the U.S. Navy, Retired Rear Admiral Bryant Fuller, who now heads up Federal Maritime Programs for Siemens Energy, knows a thing or two about powering a ship.

“Designing a power system for a ship is a very collaborative and iterative process,” he said. “There is a lot of back and forth. [A ship] is a system of systems and what you do over here will impact what happens over there. Nothing is done in a vacuum.

Siemens Energy provided the water-cooled battery system for this Norwegian all-electric ferry, which is the world’s largest electric ferry. (Photo: Siemens Energy)

“There’s a lot of implications for going with one type of technology or one type of fuel compared to another,” he continued. “There’s not a single best answer.”

Coming up with the optimal solution to power a vessel requires working with all stakeholders – the owner, naval architect, engineers, shipbuilder, etc. – to set parameters and priorities. “There are trade-offs,” Fuller said. “There’s not a magic bullet out there because everything impacts something else.”

Collaboration required

Siemens Energy was spun off from German multinational technology conglomerate Siemens in 2020 to form a standalone entity focused specifically on the energy industry. Its portfolio encompasses a diverse collection of products from electrolyzers and large gas and steam turbines for power utilities to technologies for the electrification, automation and digitalization of offshore and maritime applications.

The company provides solutions to meet varying customer needs based on power requirements, vessel size, application, time at sea, sustainability initiatives, etc. These solutions include low-voltage power generation, PEM fuel cells, battery energy storage systems, waste heat recovery systems and more.

“We provide integrated electric systems. For the marine side at least, we don’t make diesel engines,” Fuller noted. “So, we’re kind of agnostic on diesels… and the fuel that you burn in your prime mover.

“Now, we’re very interested because that is a key part in providing the propulsion system for a ship. The parameters of the ship matter. But we’re not the decision makers for what kind of [engine or] fuel you’re going to use.”

The Texas Department of Transportation is using Siemens Energy’s BlueDrive PlusC and BlueVault energy storage system technology to help the Esperanza “Hope” Andrade ferry reduce emissions, enhance performance and optimize operational costs. The ferry went into operation March 8, 2024. (Photo: Siemens Energy)

To ensure all elements will work effectively together, collaboration with the owner, naval architect, engineering firm and shipbuilder are essential. “We need to understand what the operator’s requirements are – what’s important to them. Does this vessel need to have a certain range? Does it have to have a certain degree of reliability?” Fuller pondered. “What does their duty cycle look like? How many days will they be at sea? What range do they need to go to without refueling? There’s a lot of operational factors that drive the whole design.”

Both the build costs and operational costs must also be taken into account. “You have to understand what the customer’s budget is. Even if it’s a Navy vessel or research vessel that’s operated by [some] quasi-government or government agency, there are still limits on their budgets,” Fuller emphasized.

Being brought in early can make all the difference. “Sometimes we get brought in upfront and early with the naval architecture firms, then build the system,” said Fuller. “Sometimes [they] already at least think they know what they’ve got and say, ‘Hey, go build this.’

“A lot of times, if they haven’t had somebody like us or even our competitors to advise them, they might not have got it exactly right. But most of them know their limitations... They’ll give you a basic solution, and then you go help them refine it and come up with a better solution.”

LVDC advantages

One of the more prevalent solutions finding its way into a growing number of smaller vessels is Siemens Energy’s BlueDrive PlusC power and propulsion system. This low-voltage direct current (LVDC) system incorporates purpose-built, brushless and synchronous variable-speed generator sets designed to deliver a range of frequencies and voltage for diesel, dual-fuel or gas-operated vessels.

BlueDrive PlusC utilizes a power management system to control the engines to achieve optimal speed set points based on torque capability. According to Siemens Energy, this reduces fuel consumption by regulating speed, adjusting the line-up of engines as necessary and operating the engines as minimally as possible.

“The LVDC technology with variable-speed generators was developed over a decade ago for mainly offshore vessels that needed to have high reliability and minimize their operational costs,” said Fuller. “We’re using variable-speed generators to [enable] just enough power coming out of the diesel to provide the power that you need.”

Edda Freya is an advanced, hybrid-powered construction vessel suited for operations worldwide. Touted as the world’s largest battery-hybrid offshore vessel, the Edda Freya employs Siemens Energy’s BlueDrive PlusC propulsion system and BlueVault energy storage system. (Photo: Siemens Energy)

A traditional diesel generator typically runs at top rated speed regardless of the load. “So, you’re pushing a lot of fuel to the injectors that is not getting burned efficiently,” he said. With the variable-speed gen-sets, “if the diesel is at 30% load, then it’s operating at a lower rpm and lower power level and you’re injecting less fuel into it. So, you’re saving fuel.”

According to Fuller, a number of vessel operators are seeing 20% to 30% less fuel burn with the LVDC solution. They are also seeing reduced engine wear and tear.

“Some of our operators are telling us they’re doing 20% less diesel maintenance, which is a big operational expense,” Fuller noted. “[Others] are telling us they’re eliminating an entire top-end overhaul on some of their diesels because of the way they’re operated. So, for them that’s a huge operational savings.”

Other benefits Fuller cited include a smaller footprint, fewer components and a lighter weight compared to a traditional constant speed AC integrated electric system.

Plus, the BlueDrive PlusC can be combined with the BlueVault Energy Storage System, which uses an advanced lithium-ion battery to store surplus power while the vessel is in operation and dispatch it on-demand. Such a system can provide redundancy in the event of a system “casualty.”

“You have a battery that can basically replace a full diesel generator until you can start another one,” Fuller explained. “The battery picks up the load and then a couple of minutes later, you get another diesel online and life is good again.”

World-first hydrogen-hybrid

Currently, Siemens Energy has roughly 60 vessel references throughout the U.S., with a sizable portion utilizing LVDC technology. The company has also started a project with the Canadian Coast Guard using LVDC in a multi-purpose diesel-electric vessel.

But perhaps the most notable project that Siemens Energy is involved in is for the Scripps Institution of Oceanography at UC San Diego. Scripps has commissioned a new coastal-class research vessel (CCRV) set to become the world’s first hydrogen-hybrid research vessel.

Proposed conceptual rendering of the new Scripps CCRV, which is set to become the world’s first hydrogen-hybrid research vessel. (Source: Glosten)

The CCRV’s hydrogen fuel cell-based propulsion system will work in tandem with a low-voltage DC diesel-electric power plant that will provide supplementary power for longer missions. For 75% of its operations, however, the CCRV will rely entirely on hydrogen for propulsion.

“For them, it was very important for zero emissions,” said Fuller. “Hydrogen is the way you can do that… We sized the hydrogen plant and the power systems so that 75% of the time, at least from the tank to the wake, they’re carbon free.”

The design of the hybrid CCRV is being led by naval architecture and marine engineering firm Glosten, with Siemens Energy as electrical integrator and Ballard Power and Chart Industries selected as primary hydrogen system equipment vendors. The integrated electric system provided by Siemens Energy includes the BlueDrive PlusC LVDC along with a BlueVault Energy Storage System, which will provide peak shaving and generator bridging as well as all-electric operation for short periods if needed.

“We have a very small energy storage package on there so the ship can get underway. It has three small diesel generators powering up the LVDC system,” Fuller explained. “We have 1.2 MW of fuel cells on it [provided by] Ballard, a fuel cell company out of Europe, and a 1,200-kg cryogenic hydrogen tank, which Chart Industries [is providing].”

With the initial design cycle recently completed, a solicitation is being finalized to invite bids from shipyards to build the ship, with the goal of making a shipyard selection this year.