Remote sensing of sulphur dioxide emissions of sea-going vessels through lidar
Zwaveldioxide-uitstoot van zeeschepen op afstand gemeten met lidar
26 May 2012, PDF |
63 pages |
Berkhout AJC, Swart DPJ, van der Hoff GR, Bergwerff JB
RIVM Report 609021115
RIVM developed an instrument to measure from the shore sulphur dioxide emissions of passing sea-going vessels. This instrument uses the lidar technique (Light Detection And Ranging). The instrument uses a laser beam to scan the exhaust plume from a passing ship and determine the emission, unnoticed. It was used from 2006 to 2008 to measure sulphur dioxide emissions from a large number of ships sailing on the Westerscheldt estuary and on the North Sea Canal. The highest measured emission was 37 gram per second. The total emission of sulphur dioxide in the Netherlands has been declining for many years. Since 2006, emissions from ocean shipping are declining as well, but not as fast as those from other sources. Therefore, the contribution from ocean shipping is gaining importance. In 2010, 55 percent of the Dutch sulphur dioxide emissions originated with sea-going vessels. In 1990, this was 21 percent. Sea-going ships are not allowed to use sulphur-rich fuel in territorial waters and at the North Sea. This relatively cheap fuel may be on board, though, for use elsewhere at sea. To what extent ship owners comply with this ban is not known. Traditional measurement methods involve taking fuel samples on board. This requires someone boarding the ship. The crew therefore knows a measurement is taking place and can adjust the type of fuel used. Moreover, with traditional methods, only a few ships per day can be checked. Lidar is not yet recognised as a law enforcement instrument. Therefore, no fines can be imposed based on lidar measurements only. The lidar may be used, though, to identify possible offenders. A law enforcement official may then board that ship to ascertain that the law was breached. When used in this way, the use of the lidar is cost-effective even now. This is because the lidar can measure almost all passing ships. Expensive patrol ships can then be directed to only visit those ships that are the most likely offenders. Moreover, this greatly increases the chance of getting caught. Therefore, it may be expected that fewer ships will breach the ban on the use of sulphur-rich fuel if the lidar is being used.