Marine engine emissions laws

Most of the focus in reducing petrol and diesel noise and exhaust emissions has concentrated on the automotive sector, but as car and truck emissions diminish, lawmakers are looking harder at the marine area for further emissions reduction.

In Australia, we are currently spared marine engine emissions regulations and our lawmakers seem content - for the moment at least - to let boat-engine importers supply powerplants that comply with overseas emissions legislation. However, any departure from overseas emissions standards compliance, such as through a rash of highly polluting engines targeted deliberately at non-regulated markets such as ours, could change attitudes in Canberra.

In February, 2007, the Department of the Environment and Water Resources (DEWR) conducted a comparative assessment of the environmental performance of small marine engines. The report stated:

The report calculated that one hour of operation of a boat that complies with US 2006 emission standards produces the same pollution as about 50 cars operated at a similar speed. Older style outboard engines that do not comply with US EPA 2006 limits are likely to emit around 10 times the amount of pollution when compared with conforming engines.

The DEWR report quoted from the National Pollutant Inventory where it's estimated that marine outboard engines emit approximately 2.5 per cent of the VOCs emitted in Australian urban areas. NSW's Department of Environment and Conservation estimates that during some summer weekends that level is closer to nine per cent.

"National Environment Protection (Ambient Air Quality) Measure (Air NEPM) ozone standards are being reviewed and based on current human health evidence, the argument appears to be strengthening for tighter ozone standards," the report states.

GLOBAL MARINE ENGINE EMISSIONS LAWS:

AUSTRALIA
While we await specific Australian legislation on marine engine emissions, it's to be hoped that the Australian Government will follow the practice it's adopted with respect to automotive emissions: accepting compliance with US or EEC emissions targets.

Nearly all marine engines being offered in the Australian marketplace comply with US or EEC regulations and future compliance seems assured, given that marine emissions laws follow automotive laws by a several-year gap that allows marine engine makers ample development time.

The current problem facing many Australian boat owners is the arbitrary prohibition of power boats or specific outboard types on local-council-managed inland waterways. The common blanket ban on two-stroke outboards, for example, ignores the developments that are incorporated in the latest two-stroke engines.

USA
Marine engine emissions laws originated in the USA. The first federal standards (Tier 1) for new non-road diesel engines were adopted in 1994 for engines over 37kW (50hp), to be phased-in from 1996 to 2000. The 1998 regulation introduced Tier 1 standards for equipment under 37kW (50hp) and increasingly more stringent Tier 2 and 3 standards for all equipment with phase-in schedules from 2000 to 2008. The Tier 1 to 3 standards must be met through advanced engine design, with no or only limited use of exhaust gas after treatment (oxidation catalysts). Tier 3 standards for NOx+HC are similar in stringency to the 2004 standards for truck engines.

On May 11, 2004, the Environment Protection Agency signed the final rule introducing Tier 4 emission standards, which are to be phased-in over the period of 2008 to 2015. These Tier 4 standards require that emissions of particulates and NOx be further reduced by about 90 per cent. Such emission reductions can be achieved through the use of control technologies - including advanced exhaust gas aftertreatment - similar to those required by the 2007 to 2010 standards for truck engines.

The National Marine Manufacturing Association (NMMA) said the new emissions laws constitute the largest regulatory action in the history of the US recreational marine industry.

The sterndrive and inboard emission targets are 5 grams per kilowatt hour for HC and NOx emissions, and 75g/kW-h for CO. Outboard and personal watercraft targets are about three times the standards of similar powered inboard or sterndrive engines, because they cannot easily adapt automotive engine technologies.

The first impact of the Tier 4 regulations was in California where the 2009 Tier 4 introduction date was brought forward by a year. This first Tier 4 law requires spark-ignited marine engines that develop less than 500hp to meet new emission standards, with reduced evaporative emissions from boat fuel systems. For sterndrive and inboard engines, Tier 4 compliance needs catalyst-based exhaust systems.

Large ships aren't going to be spared emissions regulations in the future. Last November, the EPA announced plans for new emission standards for diesel engines on large ocean-going vessels. The advance notice of proposed rulemaking reflects the approach set out in the US Government's recent proposal to the International Maritime Organization. Compliance with the proposed regulations will require the use of aftertreatment technology and lower sulphur marine fuels, to reduce NOx and particulate emissions.

EUROPE
In Europe, marine engine emissions are now covered by an RCD (Recreational Craft Directive - EU 2006). The original 1998 RCD was a set of safety and design criteria to regulate the construction and design of 2.5 to 24m leisure craft in Europe. During 2003, an updated version was ratified to include noise and exhaust emissions.

Noise emission levels are set by the whole craft package, so the same engine in different boats will produce different noise levels, depending on exhaust type, mounting, damping and exposure. It has been accepted that the latent pass-by noise of a boat moving through water with no mechanical propulsion system at all is an acceptable noise within the boating environment, so it is the powering of a craft at a given speed that is the key factor.

For boats powered by outboards, the RCD has defined that the noise level to be concerned with is purely that of the noise of the engine mounted on the transom, so the manufacturer of the outboard is tasked to achieve the standard rather than the manufacturer of the boat. If the engine meets the noise target of RCD EU2006, then it is defined that the boat package does too. Again, as for exhaust, there are three levels of targets: one for diesel/compression engines, one for four-stroke petrol and another for two-stroke petrol.