ARB could enforce speed limits

Vessels could be forced to reduce speeds to 12 knots within 24 to 40 nautical miles (nm) off the California coastline if the latest proposals by the California Air Resources Board (ARB) are given approval. At an ARB workshop in California, the board discussed measures for vessel speed reduction (VSR) as a way of reducing ship generated emissions. California plans to reduce greenhouse gas (GHG) emissions to 1990 levels by 2020, with further reductions through to 2050. ARB is also committed to reducing particulate matter (PM), nitrogen oxides (NOx), sulphur oxides (SOx) and carbon dioxide (CO2) under the bill.

Two approaches were discussed by the board. The first approach, a voluntary programme to encourage vessel operators and owners to reduce speeds to 12 knots within 24 or 40 nm of the major ports and along busy shipping channels. The second would involve a regulatory speed reductions, enforced by ARB. Using data provided by a number of shipping companies, ARB said that reducing the speed to 12 knots would see a reduction in emissions between 14 and 21%.

Emission reduction benefits at 24nm for 12 knot VSR measures for 2008 saw a reduction in PM of 0.9 tonnes a day, SOx decreased by 6.8 tonnes a day and CO2 saw a decrease of 418 tonnes a day. Those reductions increased substantially if vessel speeds decreased within 40nm. PM decreased by 27 tonnes per day, SOx saw a reduction of 20.1 tonnes, and CO2 decreased by 1235 tonnes a day, according to ARB data.

A spokesperson from ARB highlighted current discrepancies regarding costs incurred by vessel owner/operators due to a one-hour delay, which ranged from $145 to $5,000 an hour. During the next few weeks ARB said it will survey shipowners to get a better understanding of how VSR would effect costs.

Shipowners raised concerns that there was insufficient data on costs and that any emissions reductions in port areas could be offset by ships sailing faster outside a VSR zone. “ARB is scheduled to meet in December to discuss the outcome of the survey and to see if a regulatory approach can be taken,” concluded the ARB spokesperson.