Connect with us

Scrubbers

Scrubbers on ships: Time to close the open loop (hole), says ICCT Senior Analyst

Despite IMO’s scrubber discharge guidelines, studies show scrubber washwater and pollutants damage ecosystems and harm wildlife, states ICCT report.
Admin

Published

6 years ago

on

ICCT scrubber loophole

Environmental technical and scientific analysis nonprofit organisation International Council on Clean Transportation (ICCT) on Thursday (18 June) published an article on the negative side effects of scrubbers and offered a proposal for the eventual phasing out of the system altogether; it was written by senior analyst Bryan Comer:

In January 2020, the International Maritime Organization (IMO) reduced the maximum allowable sulfur content in shipping fuel from 3.5% to 0.5%, except for ships that use exhaust gas cleaning systems, commonly known as scrubbers. By significantly reducing air emissions of sulfur oxides, this policy is expected to improve air quality and save, conservatively, tens of thousands of lives per year. However, more than 4,000 ships have installed or ordered scrubbers to avoid using cleaner, but more expensive, low-sulfur fuels. The figure below illustrates the recent, dramatic increase in the number of ships that are using or intend to use them.

This year, about 16% of container ships, representing 36% of container carrying capacity, will have scrubbers installed; the same will be true for 15% of bulk carriers and one in ten oil tankers. What’s the issue? Well, as my colleague Elise Georgeff explains, scrubbers generate contaminated washwater that’s usually dumped overboard, and this raises questions about whether or not scrubbers should be allowed.

Indeed, a growing number of governments have restricted or banned the use of scrubbers, especially in high-traffic areas like ports and canals. For now, though, scrubbers are a legal alternative to compliant fuels in most parts of the world. As I’ll explain, this is a loophole that needs to be closed. Below I lay out a four-step approach that starts by reducing water pollution from the scrubbers we already have and ends with phasing them out completely.

But first, let’s briefly review how different scrubbers work and the risks they pose. Scrubbers come in three varieties: open-loop, closed-loop, and hybrid. Open-loop systems suck in seawater, spray it into the exhaust, and discharge it overboard, often without treatment. Instead of using seawater, closed-loop systems have a tank of alkaline-dosed freshwater onboard. After it is sprayed into the exhaust, the water is filtered to remove solid particles and then recirculated, with a small amount of “bleed-off” water discharged overboard. Hybrid scrubbers can be operated in open-loop or closed-loop mode. About 80% of scrubbers installed on ships are open-loop. Hybrid scrubbers account for about 17% and closed-loop scrubbers account for less than 2%. Open-loop scrubbers are the most popular because they are the least expensive to install and operate. Hybrid scrubbers cost more, but provide a bit of insurance against local restrictions on open-loop scrubber discharges, as they can be switched to closed-loop or zero-discharge mode. Mainly, ships use hybrid scrubbers in open-loop mode to avoid collecting and storing scrubber sludge, which needs to be disposed of on land, for a fee of course. Closed-loop systems are the most expensive and, unlike open-loop systems, continuously collect and store scrubber sludge that must be removed from the recirculating washwater.

Further, despite IMO’s scrubber discharge guidelines for pH, temperature, polycyclic aromatic hydrocarbons, turbidity, and nitrates, studies are showing that scrubber washwater and the pollutants it contains damage ecosystems and harm wildlife. A new study estimates that if 15% to 35% of the fleet (by gross tonnage) operating in the English Channel and the southern North Sea were equipped with open-loop or hybrid scrubbers, each year the pH would drop by between 0.004 and 0.010 pH units, about as much as the ocean acidifies in two to four years due to climate change. Near Rotterdam, the pH decrease was estimated at up to 0.088 pH units per year, which would normally take between 30 and 50 years from climate change.

According to our recent study focused on Canada’s Pacific coast, in 2017, 30 scrubber-equipped ships dumped 35 million tonnes of contaminated washwater near British Columbia, including 3.3 million tonnes within the designated critical habitat for threatened and endangered killer whales. Cruise ships were responsible for 90% of these discharges. Since 2017, the government of Canada more than doubled the size of resident killer whale critical habitat. Under the revised definition, 5.1 million tonnes of washwater were dumped inside these areas. (In the next year, the ICCT will estimate total scrubber washwater discharges worldwide.)

Without a global prohibition, we can expect more and more ships to take advantage of the cost savings of open-loop scrubbers, even if the pace of scrubber installations is temporarily slowed by the coronavirus outbreak. This is because, despite local restrictions, oceangoing ships spend the majority of their time on the high seas, where fuel cost savings quickly accrue. At its next Marine Environment Protection Committee meeting, which could be held virtually later this year, the IMO is expected to approve a new workplan focused on harmonizing the rules for scrubber washwater discharges. This is an opportunity for IMO to decide when, where, or even if scrubber discharges should be allowed.

Here’s my proposal for how IMO should proceed under a scrubber workplan:

Step 1. Prohibit new scrubber installations. No new or existing ship should be allowed to install a scrubber if they don’t already have one installed. All ships should use fuels that comply with the IMO 2020 sulfur regulations.

Step 2. Convert existing open-loop scrubbers to closed-loop. This would allow shipowners who have already spent millions of dollars on scrubbers to continue to use them, but would also dramatically reduce the amount of polluted water that’s dumped overboard. Closed-loop systems discharge less than 1% as much as open-loop systems, but this bleed-off water is acidic and contains a higher concentration of pollutants. So closed-loop scrubbers still pollute.

Step 3. Prohibit closed-loop bleed-off water discharges in places that should be protected. Ships with scrubbers should operate in zero-discharge mode when they are in places that governments agree should be protected. These might include critical habitats for threatened and endangered species, marine protected areas, particularly sensitive sea areas, estuaries, near-shore areas, or in ports.

Step 4. Phase out existing scrubbers over time. Ships with scrubbers do and will continue to have a market advantage over ships without because the fuel cost savings of using high-sulfur heavy fuel oil outweigh the capital, operating, and maintenance costs of the scrubber. If new scrubber installations are prohibited, then it’s only fair that existing scrubber installations be phased out. The IMO should agree on a timeframe for phasing them out.

Except for local restrictions, these changes will require IMO member states to amend the International Convention for the Prevention of Pollution from Ships, better known as MARPOL. This process will take several years to negotiate and, if agreed, an additional two years to become enforceable. In the meantime, countries, states, and ports can prohibit the use of scrubbers in the waters they control. Scrubber washwater discharges are already prohibited in all or parts of China, Singapore, several European countries, the Suez and Panama Canals, California, Connecticut, Hawaii, and in major ports such as Fujairah.

While local actions are a good start, they are not sufficient. The four steps above can serve as a recipe for uniform, global action on scrubbers that closes the open loophole.


Photo credit and source: ICCT
Published: 23 June, 2020

 

Related Topics:
Continue Reading

ECA

VPS examines North-East Atlantic ECA on current bunker fuel mix and testing

Impact of this new ECA, will not only affect bunker fuel selection and testing, but it will also require a review of, voyage planning, bunker procurement and scrubber strategy, amongst others.

Admin

Published

3 weeks ago

on

May 14, 2026

By

RESIZED VPS logo

Steve Bee, Group Marketing and Strategic Projects Director, and Emilian Buksak, Decarbonisation Advisor of marine fuels testing company VPS, on Wednesday (8 April) highlighted MEPC 84 approved a new emission control area (ECA) covering the North-East Atlantic Ocean, with agreements reached on adopted amendments to MARPOL Annex VI. 

The new ECA, which will become the world’s largest emission control area, will be implemented on 1st September 2027

In a recent article, VPS outlined how VPS testing, data, CEM systems and advisory services can support vessels in both their operational and compliance challenges associated with this new ECA:

The recent International Maritime Organisation’s (IMO), Maritime Environmental Protection Committee (MEPC) meeting in London, had its main focus on setting binding greenhouse gas emission reduction targets for the global shipping sector. In keeping with the Committee’s continuing drive to decarbonise shipping and reduce the pollutant emissions from the global fleet, one major outcome from the MEPC-84 meeting was the approval of a new emission control area (ECA) covering the North East Atlantic Ocean, with agreements reached on adopted amendments to MARPOL Annex VI.

This new ECA, which will become the world’s largest emission control area, will be implemented on 1st September 2027, with the ECA requirements taking effect on 1st September 2028. It will cover the territorial seas and exclusive economic zones of Greenland, Iceland, the Faroe Islands, Ireland, the United Kingdom, France, Spain and Portugal, extending up to 200 nautical miles from their baselines:

VPS examines North-East Atlantic ECA impact on current bunker fuel mix and testing

A key advantage of the new NE Atlantic ECA is that it will close the gap between the existing ECAs in the North and Baltic Sea, plus the Mediterranean, creating an almost continuous zone of reduced shipping emissions. It will also connect to the newly approved ECAs in the Canadian Arctic and Norwegian Sea, which are scheduled for implementation in 2026 and 2027 respectively. Together these ECAs will cover almost half of all Arctic coastal waters, improving air quality, by reducing SOx, NOx and Particulate Matter (PM), protecting  public health, and reducing the environmental impacts from shipping.

The sulphur limit for the marine fuels allowed to be burnt within this new ECA will reduce from the current 0.50% to 0.10%. This will force vessels to use either effective abatement technology (scrubbers), or alternatively burn marine distillates, ultra-low-sulphur fuels (ULSFOs), or biofuels with a sulphur content of less than 0.10%.

Without doubt this new ECA will cause a significant change to the current fuel mix, probably on an even greater scale than was witnessed with the introduction of the Mediterranean ECA back in May 2025.  The fuel mix in the Mediterranean Pre-ECA implementation was,  53% VLSFO, 28% HSFO, 16% MGO, 2% ULSFO and 1% Biofuels. But from the 1st May 2025, the fuel mix changed to, 30% VLSFO, 29% HSFO, 30% MGO, 8% ULSFO and 4% Biofuels.  

So, in terms of actual tonnage, the Mediterranean ECA witnessed a decrease in VLSFOs by 23%, whilst MGO usage increased by 107%. At the same time, ULSFO and biofuels supply increased 4-fold.

Regarding fuel quality within the Mediterranean post-ECA implementation, MGO off-specification rates increased to 4%. However, the most worrying off-specification rates were for ULSFOs which saw a 10-times increase from 2% to 20% from the start of the ECA, with the main off-specification parameters being pour point, sulphur, TSP, CCAI, water and viscosity.

Therefore, it is fair to assume we’ll witness a similar dramatic fuel mix change upon the implementation of the NE Atlantic ECA, with possibly similar fuel off-specification issues, highlighting the continuing need for proactive fuel testing to protect vessels, crew and the environment.

Whilst the focus on fuel quality is essential, the multi-pollutant nature of this new ECA, covering SOx, PM and NOx, also brings the role of continuous emissions monitoring increasingly to the fore. Therefore, a further consideration relating to the impact of this new ECA relates to vessel newbuilds and the stricter NOx Tier III requirements. For newbuilds subject to the stricter NOx Tier III requirements, compliance depends not only on engine certification at delivery, but on demonstrating that exhaust after-treatment systems, typically Selective Catalytic Reduction (SCR) or Exhaust Gas Recirculation (EGR), continue to perform as designed throughout the service life of the vessel.

For scrubber-equipped ships, real-time SO₂ measurement provides the operational evidence of equivalency that Port State Control inspections increasingly expect to see. Plus, for vessels operating under multiple overlapping regulatory regimes, including the new NE Atlantic ECA, EU MRV, EU ETS and FuelEU Maritime, continuous emissions monitoring via the VPS EMSYS CEM system delivers a single, verified source of emissions data that can be applied across all of them.

As noted by DNV in their MEPC 84 technical and regulatory update, the newly adopted IMO measurement guidelines can also be used for determining actual methane and nitrous oxide under the EU ETS and FuelEU Maritime, confirming the direct route from IMO-recognised measurement to EU compliance reporting.

At an operational level, the new ECA will introduce considerable complexity in the way fuel consumption is attributed across voyage segments, with VLSFOs burnt outside the zone and compliant fuels inside, all of which carry implications for consumption reporting, charterparty allocation and EU MRV alignment. VPS Maress can provide the underlying fuel and energy data into one auditable platform, helping crews manage the operational complexity that the new ECA introduces, including voyage segmentation, fuel changeover and emissions accounting, plus providing the consolidated data foundation that feeds existing EU MRV and IMO DCS reporting obligations. 

VPS PortStats via the VPS Verisphere eco-system, (VeriSphere | VPS), further supports bunker procurement planning with port-by-port intelligence on compliant fuel availability and price spreads. Such intelligence and insights, will prove particularly valuable in the months immediately following 1st September 2028, when the supply pressure on 0.10% sulphur fuels is likely to peak.

Regarding the more strategic decisions ahead, including Tier III engine selection for newbuilds, retrofit feasibility for existing tonnage, and charterparty clauses allocating the ECA fuel cost premium between owners and charterers, VPS Advisory Services can provide the integrated commercial and technical perspective needed to navigate this transition with confidence.

Therefore, its clear the impact of this new ECA, will not only affect the choice of fuel to be burnt onboard and its subsequent quality testing, but it will also require a review of, voyage planning, bunker procurement, scrubber strategy, engine certification, compliance documentation and charterparty exposure.

Related: DNV on IMO MEPC 84: Revisiting Net‑Zero Framework

 

Photo credit: VPS
Published: 14 May, 2026

Continue Reading

Scrubbers

No open-loop EGCS with HSFO bunker fuel allowed in Saudi Arabian ports

Use of HSFO with an Open-Loop Exhaust Gas Cleaning System at 0.5% or 0.1% sulphur mode setting is prohibited until further notice for the ships entering Saudi Arabian ports, says GAC.

Admin

Published

6 months ago

on

December 8, 2025

By

Aramco: Ras Tanura Port, Eastern Province of Saudi Arabia, on the Arabian Gulf.

The use of High Sulphur Fuel Oil (HSFO) with an Open-Loop Exhaust Gas Cleaning System (EGCS) at 0.5% or 0.1% sulphur mode setting is prohibited until further notice for the ships entering Saudi Arabian ports, according to GAC Hot Port News on Wednesday (3 December). 

All ships entering Aramco ports shall comply with one of the following options:

  • Use compliant fuel oil (≤ 0.50% m/m Sulphur, or ≤ 0.10% when operating in ECAs, if applicable).
  • Operate the EGCS in Closed-Loop mode (or Hybrid system in Closed mode), with strict prohibition on the discharge of wash water into the sea.

 

Photo credit: Aramco
Published: 8 December, 2025

Continue Reading

Bunker Fuel

Equatorial navigates through sanctions and green transition amid shifting bunkering landscape

Shipowners’ demand for ‘cheapest compliant fuel’ suggests a potentially more competitive and shrinking market for LSFO, forecasts Choong Sheen Mao, COO at Equatorial.

Admin

Published

6 months ago

on

December 1, 2025

By

Equatorial navigates through sanctions and green transition amid shifting bunkering landscape

Singapore-based physical bunker supplier Equatorial Marine Fuel Management Services Pte Ltd (Equatorial) is adapting to a dynamic global bunker market shaped by regulatory shifts, geopolitical tensions, and the push for decarbonisation, states its Chief Operating Officer.

Choong Sheen Mao was amongst panellists of the Bunker Sellers Panel at IBIA Annual Convention 2025 in Hong Kong on Tuesday (18 November) when he shared a significant trend of shipowners increasingly opting for high sulphur fuel oil (HSFO) paired with scrubbers, driven by the pursuit of the “cheapest compliant fuel”.

Despite a narrowing spread between high and low sulphur fuels – from approximately USD 125 to USD 80, and occasionally below USD 70 – shipowners continue to see long-term investment returns from scrubbers. This shift suggests a potentially more competitive and shrinking market for low sulphur fuel oil (LSFO).

“Geopolitical instabilities, particularly armed conflicts, sanctions and trade wars, are creating considerable market distortions. These instabilities lead to supply disruptions, cargo rerouting, and impact bunker prices,” added Choong.

“Compliance has become a paramount concern, with recent substantial fines underscoring the risks involved. The current economic slowdown, compounded by sanctions and self-sanctioning, presents a ‘double pain’ for the market.

“The market’s daily volatility is also heavily influenced by global politics, making it challenging to assess without a deep understanding of geopolitical events.”

To ensure marine fuel quality, Equatorial emphasises managing its own supply chain and operating its own fleet of bunkering vessels, allowing for direct control from delivery to the customer, he stated.

This approach prioritises transparency and security, fostering long-term relationships where quality issues can be collaboratively addressed. Knowledge sharing, especially concerning parameters from new bunker fuel testing methods such as Gas Chromatography Mass Spectrometry (GC-MS), is also deemed crucial.

Supporting the transition to alternative marine fuels, while acknowledging the uncertainty surrounding the dominant future fuel, Equatorial has strategically invested in IMO Type 2 chemical tankers capable of handling methanol, biofuel, and conventional bunker fuels.

“Biofuel is identified as the most effective short-term solution, offering favourable pricing and operational costs compared to other green alternatives,” explained Choong.

“However, challenges include feedstock availability and potential export quotas from key producing nations like China.

“The adoption of alternative marine fuels necessitates a closer, more collaborative relationship between buyers and sellers.

“This involves detailed discussions on specific fuel specifications beyond standard ISO requirements, extensive lab sampling, and long-term commitments from both parties, particularly given the absence of a liquid hedging market for biofuels.

“Collaboration across safety, quality, and commercial aspects is essential for the successful implementation of bio bunker fuels to the future maritime market.”

 

Photo credit: International Bunker Industry Association
Published: 1 December, 2025

Continue Reading

Trending