Delivering clean power for the future
10 years of LNG at sea
The marine industry relies on fuel oils for most powering needs, but tighter emission regulations and the need to ‘go green’ are starting to convince operators to consider alternatives. Our gas engines have proven themselves to be the cleanest, most efficient piston engines on the market. Since the introduction of the Bergen lean-burn technology more than 700 gas engines have been delivered and over 31 million operating hours accumulated at sea and on land.
Mixing gas and air together for combustion at the right time is crucial to maximizing the efficiency of our engines. Bergen lean burn gas engines turn around 50% of the energy in the fuel into power at the flywheel. If a waste heat recovery system is added this figure could potentially rise by a further 20%, depending on the technology used.
The lean burn system combines spark-ignition with a prechamber, so the engine uses a lean mixture of gas and air. At the start of the compression stroke a valve feeds the right amount of gas for ignition into the prechamber, where it is ignited by the spark plug at the right moment.This charge is directed into the cylinder, bringing enough energy to ignite the lean mixture.
Advanced control systems meter the gas, control the air pressure, valve and ignition timing. Knock sensors detect changes and adjust the control system, ensuring methane slip is reduced to very low levels. The engine combustion technology is robust and ensures that the engines can operate on a wide range of gas qualities.
“Using the Kongsberg Maritime Power Management system, engines can be run at their most efficient load, minimising fuel consumption and helping our customers cut their total emissions.”
Bergen gas engines fulfil the requirements for operation in ECAs (Emissions Control Areas), and meet IMO Tier III emission regulations due to come into force in 2016. The total greenhouse gas (GHG) emissions are about 22% lower than a comparable diesel engine, even including the effects of methane slip.
Exhaust emissions from ships have come into much sharper focus because of national and international rules phased in since 2005. The latest 0.1% sulphur directive effective Jan 1, 2015 has left the shipping industry with a choice on how to respond and meet the latest requirements for operating within an ECA.
The Eidsvaag Pioner was the first of the Environship vessel design concept from us, introducing innovative energy saving and emission reducing technologies.
Delivering the right level of power at the right time is critical for marine operations and safety. Rolls-Royce Bergen gas engines respond as well as their diesel counterparts. Variable turbocharger geometry responds quickly to throttle changes, delivering the torque necessary to meet the increased power demand, and fuel efficiency throughout the power range.
“The engines are very responsive. The tugs respond as well in operation as their diesel counterparts.”
Engine rooms on gas powered vessels stay much cleaner, saving operators time and money by reducing the frequency of cleaning tasks and the cost of chemicals. Crews really appreciate the clean, safe working environment, too.
Pure gas engines use only natural gas as fuel, so there is negligible sulphur in the exhaust and virtually no particulates. This means there are no visible exhaust emissions, and no contamination to the lube oil. The lube oil in Bergen gas engines stays in such a good condition that purifiers are not necessary and oil changes are not normally required – only topped up when the level is low.
“It’s a completely clean engine. There’s a lot less maintenance than on a diesel engine – we’re saving a good five or ten per cent in maintenance costs. Most of the time, we just fill up with gas, and off we go.”
Bergen gas engines are defined as inherently safe because they use double walled pipe to lead the gas all the way into the combustion chamber. On a vessel the whole LNG System is designed with double walled containment; the tanks, the pipes and the engine itself.
Throughout the system, both the LNG and the gas are contained within two barriers of stainless steel. The system is controlled by the Acon LNG system, which ensures the highest standards of safety on board by detecting and containing leaks between the inner and the outer barriers. Thanks to these safety measures, engine rooms on Kongsberg Maritime powered vessels are considered just as safe as diesel engine rooms.
“The Bergen gas engines are safe and simplifies vessel design.”
With gas engines, as much as 10% of the total engine power can be recovered from wasted exhaust heat.
Internal combustion engines generally lose around 30% of their energy through the exhaust as heat. Diesel vessels struggle to recover this heat because of the build up of particles, and corrosion issues from the sulphur in the exhaust. However, gas powered vessels enjoy a negligible sulphur content, so they can transfer more exhaust heat into the vessel’s waste heat recovery system.
The recovered exhaust heat can be converted into electricity via a steam generator. This additional power can then be fed into the propulsion system or used to supply power to other equipment on board. Studies have proved that as much as 10% of the total engine power can be recovered from wasted exhaust heat, making it an attractive option for further improving performance, particularly for larger cargo vessels and passenger ferries.
“The waste heat recovery system is one of the four important elements in these ships which give them exceptional efficiency and low emissions.”
Explore our ship systems
We tailor the entire system design, combining gas engines with an efficient propulsion system to meet individual customer needs and the operating profile of the vessel. We can also add an efficient hull design, and – if needed – a hybrid solution with PTI / PTO to provide system flexibility. Our delivery also includes a complete automation and control system where all equipment is interfaced with optimum efficiency and operating economy.
Passenger | Features
Cruise Ships and Ferries are perfect candidates for pure LNG fuel because they mainly operate in densely populated or pristine areas where emissions are both visible and a danger to people’s health and the environment. In fact, removing the risk of soot falling onto passenger decks was the initial challenge that got us started looking at emissions from passenger vessels.
Now, rising fuel costs and ever more demanding regulations have made fuel efficiency and emission control the main concerns for passenger ship operators. Passenger ships are highly visible to the general public and LNG is a safe and environmentally friendly fuel. Operators are discovering the benefits of operating on natural gas and most crews would prefer not to work on conventionally fuelled vessels again.
Cargo | Features
Rolls-Royce Bergen medium speed gas engines are an ideal choice for short sea shipment vessels.We tailor the entire system design, combining gas engines with an efficient propulsion system to meet the customer’s needs and the operating profile of the vessel. We can also add an efficient hull design, and – if needed – a hybrid solution with PTI/PTO to provide system flexibility.
Rolls-Royce Bergen gas engines deliver a significant reduction in fuel and lubrication oil consumption. In addition, the clean, safe engine rooms and state-of-the-art technology attract the best crew on the market.
Tug | Features
Ever stricter environmental regulations are pushing ship owners and operators towards cleaner energy sources. Our gas propulsion system powered by Liquefied Natural Gas (LNG) has proven to offer the optimum route to cost-effective environmental compliance.
We provide a complete gas powered propulsion system from the bunkering flange to the propeller thrust, comprising gas fuel system, gas engines, Azimuthing thrusters, automation and control systems. All equipment is interfaced with optimum efficiency and operating economy.
Offshore | Features
Stricter environmental regulations plus demand from operators have challenged suppliers to come up with cleaner, more efficient power systems. Our answer to this challenge is pure LNG engines in combination with efficient diesel-driven engines. Our designed UT vessels with gas / diesel / electric systems have proven to offer the optimum route to cost-effective environmental compliance.
The Rolls-Royce Bergen lean burn gas engines create a better working environment for crews on board the PSV and on the rig. With almost 800 UT vessels with a range of designs in operation, we’ve proved that we have the qualities and the competence to offer the most comprehensive integrated system for the Offshore Supply Industry.