25 July 2008

The California Air Resources Board (ARB) voted to approve a new emission regulation for ocean-going ships. As proposed last month, the adopted final rule requires ocean-going vessels within 24 nautical miles of California’s coastline to use lower-sulfur marine distillates in their main and auxiliary engines and auxiliary boilers, rather than the high sulfur heavy-fuel oil (bunker fuel).

New marine engine regulations were also adopted this week by the US federal government. President Bush signed into law the Maritime Pollution Protection Act of 2008, which clears the way for US ratification of the International Maritime Organization’s (IMO) MARPOL Annex VI convention that regulates emissions from large diesel-powered, ocean-going vessels. The final step of the ratification process is for the President to deliver a letter—known as diplomatic instrument of ratification—to the IMO.

The California regulation is to be implemented in two steps:

  • From July 2009, ocean ship main engines, as well as auxiliary engines and boilers will have to switch to either marine gas oil (MGO) of maximum 1.5% (wt) sulfur or marine diesel oil (MDO) of maximum 0.5% (wt) sulfur.
  • From January 2012, ocean ships must switch to a MGO or MDO fuel of maximum 0.1% sulfur.

About 2,000 ocean-going vessels visiting California ports annually, both US- and foreign-flagged, are subject to the regulation.

The IMO MARPOL Annex VI emission rules entered into force in May of 2005, although ships have met most provisions since 2000. While the current IMO requirements, known as IMO Tier 1, are rather relaxed, IMO members reached agreement on more stringent Tier 2/3 regulations. The MARPOL Annex VI legislative amendments are expected to be finalized in October.

The legislation signed by President Bush also authorizes the US Environmental Protection Agency (EPA) to petition the IMO to designate the United States as an “emission control area” (ECA). This would trigger a Tier 3 NOx limit (3.4 g/kWh) effective 2016, and a 0.1% sulfur limit starting in 2015 for ships near US coasts.

While the 0.1% sulfur limit under the California regulation and under the MARPOL Annex VI ECA requirements is the same, the California rule becomes effective in 2012, three years earlier than the IMO standards. Therefore, the California ARB has called its rule the “world’s strictest diesel emission regulation”.

An earlier California rule, which required low sulfur fuel in ships auxiliary engines, was struck down by a court in response to a legal challenge by the Pacific Merchant Shipping Association (PMSA). The PMSA has not yet issued a position on the new California ARB regulation.

Source: California ARB | US EPA