If you own, operate, service or build marine diesel engines, you probably already know that emission standards for these engines started getting tighter in the the mid-90s, and the regulations, both national and international, are ratcheting up almost every year for the next several years.
- the first-ever emissions standards for remanufactured engines with capacity more than 600kw
- emission standards for newly-built engines, which began in 2009
- emission standards for newly-built engines with "high-efficiency catalytic after-treatment technology" built beginning in 2014.
- Use of biodiesel. Biodiesel produces much reduced PPM, NOx is another matter. Some laboratory studies show more NOx emissions in biodiesel than in standard diesel, while some "real world" studies show the opposite. Almost all the studies were conducted in a non-marine environment.
- Electronic controls. Replacing mechanical valves, cylinders, and fuel injectors -- the latter often combined with high-pressure pumps -- with electronically-controlled ones can not only reduce emissions, but increase fuel efficiency.
- Repowering. Several manufacturers such at MTU, Lugger, and John Deere are building diesel engines specifically geared to meet the new emission standards, but other companies are looking at alternative ways to meet the requirements. A recent trial by Foss Maritime found significantly reduced emissions, fuel costs, and engine hours by switching to the engine/battery hybrid technology similar to that used by automobiles like the Prius. Smaller vessels are finding microturbine gas engines efficient and needing less periodic maintenance.
- Processing emissions. Generator exhaust in particular can be reduced by filtering it with water, or using catalytic or heating elements.