Measures for the discharge of wash water from EGCS. Economic impact of measures to reduce the discharge of wash water from EGCS

Since 1 January 2020, the International Maritime Organisation (IMO) has set a lower limit on the amount of sulphur permitted in marine fuel. There are several measures shipowners can take to reduce sulphur emissions. One such measure is the application of emission-reducing systems, also known as Exhaust Gas Cleaning Systems (EGCS). These systems use seawater to wash exhaust gases, allowing ships to run on heavy sulphur fuel oil (HFO).

The potential environmental impact of washwater discharges from EGCS are increasingly being debated, especially discharges near the coast and at ports. Several countries and ports have adopted measures banning discharges of EGCS in territorial waters or ports. These bans are mostly for discharges from open-loop systems (these systems discharge washwater overboard), but also for discharges of bleed-off water from closed-loop systems (these store sludge and produce limited surplus water – the bleed-off water). The Ministry of Infrastructure and Water Management (Ministerie van Infrastructuur en Waterstaat) requested CE Delft to investigate the economic impact of measures that reduce washwater discharges from Dutch-flagged vessels, Dutch shipping companies and Dutch producers of EGCS.

The main conclusions are:

  • For national bans, the increase in costs depends on the zone in which the ban applies. A global ban in territorial waters within 12 nm of the coastal border has substantially more impact than local bans in ports.
  • The impact differs between ships. There are ships where effects will be greater, because they consume a lot of fuel in ports or sail frequently along the coast.
  • Specifically concerning the Netherlands, transit shipping routes are relatively limited in territorial waters located within 3 nm, and a national ban will have a limited effect on ships that visit occasionally.
  • The potential to use hybrid or closed loop scrubbers in response of a ban is limited due to available storage space on board.

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