Diesel engines are greener than electric engines? In some cases, yes!


There has been a lot of recent publicity regarding the development of electric vehicles, and in addition, electric propulsion for marine use. Much of what is said highlights the reduced emissions from electric propulsion. It is true: electric engines can be cleaner than diesel or other petroleum engines. However, the media usually neglect an important fact, and that is that electric engines need to be charged somehow. That somehow usually means connecting to the power grid. Depending on where the engine is used, the carbon footprint of that electric engine can be much higher than that of an equivalent diesel engine. In regions where the bulk of electricity is produced by coal or other dirty fuels, that electric engine actually produces up to four times the amount of CO2 as a modern diesel engine.

The diesel fuel in 2015 is not the same as your grandfather’s diesel fuel. Modern diesel fuel is cleaner than ever before. All diesel emissions from vehicle use can be minimized and controlled, depending on the emission type. Right now, in the EU, there is some controversy regarding the fact that even though the introduction of ULSD reduced SOX emissions, there was an increase in particulate matter emissions (PM) and NOX emissions. However, PM can easily be reduced by filtration, and NOX can be reduced by the use of a SCR.

When compared to the use of electric propulsion, on the surface it can seem that the electric engine will produce fewer emissions at lower cost. Yet, when you compare the emissions and cost of charging, with the lower efficiency of electric engines (they are typically larger and heavier than diesels, with lower power output), the advantages of electric become less clear and straightforward. One additional problem that electric engines for marine use have faced is the limited range (electric cars don’t have the same issue as much on land): Limited range means limited places to charge. This fact has restricted the use of electrical engines to hybrids or coastal use.

MarineDiesel is in compliance with all emissions regulations in the EU and North America. Our engines can be used in regions with the strictest emissions standards and regulations (like the polar regions). Our research and development team are constantly modifying and improving the fuel efficiency of our engines, and reducing the emissions they produce.

If you want to learn more, there is an interesting discussion of the subject at Shrinkthatfootprint.org