Remote Measurements of Ship Emissions

• The combustion of sulphur-containing fossil fuels gives rise to emissions of sulphurdioxide. Nitrogen oxides are also emitted when fuels are burned. The InternationalMaritime Organization (IMO) has ratified regulations regarding Sulphur Fuel Content(SFC) and NOx emissions from the shipping sector. There is economic incentive to ignorelegislation and run with cheaper residual fuel that contains high concentrations of sulphur.In open waters, there is no effective method of controlling whether ships are running onlow or high sulphur fuel.A surveillance system, denoted Identification of Gross Polluting Ships (IGPS), has beendeveloped and used with the objective of enforcing the use of low sulphur fuel and NOxabatement equipment according to the new conventions within the IMO.The system is foremost an airborne system consisting of an optical remote measuringsystem for total emission measurements of SO2 or NO2 from ships. When the emissionvalues reach a certain threshold, an aircraft flies into the ship’s exhaust and takes in situmeasurements, denoted the sniffer system, from which SFC and NOx g/kg fuelmeasurements are obtained.The uncertainty for the optical measurements is estimated to be approximately 45% withoptical and wind as the largest uncertainty sources. Estimates of the overall uncertaintyfor the sniffer measurements, derived during a campaign in Rotterdam, corresponds to14% for SO2 (S%) and 33% for NO (g/kg fuel). For the emission factors of NOx versusaxial power, g/kWh, the uncertainty is 37%. It should be noted that the NO uncertaintywas unusually high due to instrument problems.Measurement campaigns have been carried out in the Baltic and North Seas using aCASA-212 aeroplane and a Dauphin helicopter. Optical measurements show thepossibility to detect SO2 and NO2 emission from ships. Many of the ocean going shipshad a total emission of 60 kg/h SO2. The sniffer measurements showed good agreementwith the current IMO regulations for the majority of ships. When the strictest IMOregulation of 0.1% SFC is introduced, ships using fuels with 0.5-4.5% SFC will be easilydetected with the current uncertainties.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

airborne

Ship emissions

sulphur dioxide

nitrogen dioxide

DOAS

in situ measurements

carbon dioxide

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