Shipping is vital to the world economy. It is a critical part of international import and export markets and supports the global distribution of goods (About 95 percent of all goods and raw materials transported globally are carried by ships). As for all industries, concerns about climate change require the reduction of greenhouse gas emissions from the shipping sector. This entails higher fuel prices for low sulphur fuels. It means that the industry must prepare for the new future and investigate alternative, more economic ship propulsion systems.
The diesel engine is currently the most widespread of vessel prime movers. It is a well-understood technology and a reliable form of shipping propulsion and auxiliary power generation.The combustion engine industry faces huge challenges regarding the significant reduction of harmful emissions. Over the past years, the contribution of emissions from shipping to the overall emissions has been reduced considerably. Acc to the latest IMO study contributes the worldwide maritime navigation at only 2.2 percent of the worldwide CO2 emissions.This tendency needs to be maintained in the future to demonstrate the ecologic advantages of shipping as an efficient means of international transport.
In the immediate future, SCR catalysts, Otto-Gasengines or Dual-Fuel engine concepts will be applied to comply with the IMO emission limits. In addition to the IMO requirements, solutions for a significant reduction of particulate emissions will become necessary very quickly. Generally, a vast number of promising emission reduction technologies for large Diesel engines are already known. Some of them have been tested successfully at test beds and pilot installations. Substantial efforts in research and development will be necessary to transfer these concepts to industrial applications and reliable products. In this context, the quality of fuel available for future large marine diesel engines is of central importance.
It can be assumed that, not later than 2020, fuels with less than 0.5 percent sulphur content may be used worldwide. The fuel sulphure content with the use of scrubbers is not decisive. With this heavy fuel oil has still a long future. Different studies assume that by the year 2030 significantly more than half of all vessels will use heavy fuel oil. Wether with 0.5 percent sulphure or with scrubbers will depend on the mineral oil groups and the respective producer countries which affect prices. Despite of first tests on board with low-sulphure fuel, it might be possible that the mineral oil industry shy away from expenses for the conversion of the raffineries which means that the scrubber will be a focal point. Low-sulphure fuel is still a residual oil with much of by-products – with the use of scrubbers a large part will be washed out. Not to forget: the correct disposal of this waste must be ensured. ”….however, diesel engines will continue to produce CO2 emissions as well as NOX, SOX, volatile organic compounds and particulate matter (PM)”, explains Dr. Udo Schlemmer-Kelling, Executive Engineer Technology at FEV GmbH.
The editorial department of VEUS-Shipping wanted to know what the combustion engine manufacturers are doing to overcome the future challenges in terms of emission reductions and talked to Ole GrØne, Senior Vice President and head of Sales & Promotion MAN D&T.
VEUS-Shipping: Exhaust emissions are a topical issue around the world: What will be the future development activities on combustion engine from a manufacturer point of view?
Ole GrØne: The engine designers like our company are concentrating on developing technologies and methods in order for the engine manufacturers that is our licensees to deliver engines which will comply with both current and coming emission control rules, limiting the emission of both SOx, NOx and not to forget CO2.
VEUS-Shipping: Will the Diesel- or the Otto-Gasengine have a bright future? Or is it the Dual-Fuel engine?
Ole GrØne: We believe that Dual Fuel Engines, i.e. engines that can use both liquid fuel and gas, will prevail, because it will most likely take decades before gas is as readily available everywhere as are liquid fuels. Therefore Dual Fuel Engines will prevail over Otto-Gasengines, and therefore the Dual Fuel Engines selected will have to be able to comply with all emission regulations in both liquid fuel mode as in dual fuel mode, eventually, especially now where also North Europe will be a NOx regulated area, like North America is today.
Dual Fuel Engines can be either using the Otto cycle or the Diesel cycle. Diesel cycle Dual Fuel Engines like MDT’s ME-GI has traditionally a higher efficiency, i.e. lower CO2 emission, than the Otto cycle Dual Fuel Engines used by MDT’s 2-stroke engine competitors. However, Diesel cycle Dual Fuel Engines have, due to their higher efficiency, a higher NOx emission to be handled by NOX abatement technologies, than the lower efficiency Otto cycle Dual Fuel Engines, which in turn have a significantly higher Methane slip. Methane slip is, calculated as CO2 equivalent, a very severe Green House Gas that is expected to be limited by regulation in the future, and therefore call for abatement technologies as well.
VEUS-Shipping: In respect of propulsion technologies, will the before mentioned engines play an important role in the future?
Ole GrØne: Some time ago one of the major oil companies predicted that in 2040 only about 10 % of ships fuel will be natural gas. The rest will be liquid fuel, half and half as either low Sulphur distillates or as High or Low Sulphur Heavy Fuel. With the introduction of a global Sulphur cap for all after the start of 2020, this could change in favour of more natural gas but surely in favour of more Low Sulphur fuels being made available. Hence the population of Dual Fuel Engines will increase, but the majority of engines will for a foreseeable future be liquid fuel burning, only.
VEUS-Shipping: Is hybrid tech a possible alternative, combined with the latest engine technology?
Ole GrØne: Hybrid technologies in the form of modern diesels with electrical Power-Take-Off / Power-Take-in systems supported by large accumulators are already in service on ferries and other types of short sea shipping vessels with four stroke medium speed engines. On long haul vessels with two stroke engines, it is with the present accumulator technology, i.e. energy storage systems, unpractical because of the space requirement of the accumulators.
VEUS-Shipping: Please explain the term “latest engine technology”?
Ole GrØne: Within our technologies sphere we see the Diesel Engine as the preferred propulsion prime mover for ocean going ships for decades to come. There will be other solutions, either stand alone or as combined systems with steam and gas turbines for some applications, but for main stream higher efficiency diesel engines with enhanced digital control and emission control will prevail.
VEUS-Shipping: Will we see 2-stroke as well a 4-stroke combustion engines in the long future?
Ole GrØne: Both types will be around for decades to come, each type with its own application advantages for different types of ships.
VEUS-Shipping: Is MAN D&T concentrating on alternative fuels (natural gas, bio-fuels, etc)?
Ole GrØne: MDT is studying all conceivable fuels. Apart from traditional liquid fuels, also such with data beyond traditional specification limits, we have already Natural Gas (Methane), Methanol and Biofuel Engines in service in the field. We have Ethane Engines on order soon to be delivered and are proceeding with developing systems for LPG burning engines. Even coal in different form has been tested, but not yet cleared for marketing. However, in our opinion liquid fuel will not go away overnight. To underline this see our report / development status / results of our ME-GI and ME-LGI Gas Technologies.
VEUS-Shipping: Mr. GrØne thank you for the talk