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Fuel Testing

VPS: Cold flow characteristics of biodiesel blended petroleum distillates

Dr. Sunil Kumar highlights how environmentally friendly biodiesel bunker blends can be negatively impacted by cold weather environments and how VPS testing methods could help ship operators ensure safe navigation through low temperatures.

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Dr. Sunil Kumar of marine fuels testing company VPS on Tuesday (12 March) discussed how environmentally friendly biodiesel blends can be negatively impacted by cold weather environments. 

The article also highlighted VPS offering various test methods in place to evaluate the cold flow property of the biodiesel blended fuels, which can help the ship operators to make the right decision how to handle the fuel at low temperatures: 

Environmentally friendly fuels like biodiesel blended with petroleum distillates can have an impact on the cold flow property. Currently biodiesel is one of the choices which is renewable, biodegradable, and less toxic compared to fossil fuels. Biodiesel significantly reduces carbon dioxide, carbon monoxide, sulfur oxides, volatile organic compounds, particulate matter, and unburned hydrocarbons when compared to petroleum distillates like Marine Gas oils (MGO), very low sulfur fuel oil (VLSFO) and Heavy fuel oil (HFO).

Cold flow prediction of biodiesel blended petroleum distillates is very important when a ship is sailing through cold weather regions. The cold flow characteristics of a blended fuel can be different from the individual fuels used for blending. MGO, VLSFO and HFO basically originate from fossil fuels whereas biodiesel is from a renewable source. Both are essentially hydrocarbons but contains compounds with different structural characteristics and properties. So, the structural difference of the compounds responsible for the cold flow property shall be considered since it is a physical phenomenon. This will have an impact on the cold flow property of the fuel since the blend is from two different origins and can sometimes lead to unpredictable paraffin agglomeration.

Veritas Petroleum Services (VPS) has various test methods in place to evaluate the cold flow property of the biodiesel blended fuels. The Laboratory determined test results can help the ship operators to make the right decision how to handle the fuel at low temperatures. 

Cold Flow Property of Biodiesel, MGO, VLSFO and HFOBiodiesel, MGO, VLSFO, and HFO share a common characteristic: the presence of polymethylene groups influencing cold flow properties. The severity of low-temperature flow centers on the amount of heavier paraffins present, with longer polymethylene chains exacerbating the impact. Biodiesel, while advantageous in many respects, falls short in cold flow performance, prone to wax crystallization in colder climates, leading to potential filter blockage and potential engine damage. The composition of these fuels, particularly the presence of saturated and unsaturated paraffins, significantly affects their cold flow properties. Different feedstocks for biodiesel production yield varying performance in low temperatures; for instance, palm oil-based biodiesel fares worse than soybean-based biodiesel due to differing paraffin characteristics. Origin, whether plant or animal-based, profoundly influences cold flow properties, necessitating meticulous evaluation, especially in blends with MGO, VLSFO, and HFO. Proper assessment of low-temperature behavior is critical for blended fuels with diverse sources and characteristics.

VPS Laboratory Scale Evaluation

There are several test methods used to determine the cold flow characteristics in fuels like MGO, VLSFO, HFO, biodiesel, and their blends. VPS utilises four main methods: Cloud Point (CP), Pour Point (PP), Cold Filter Plugging Point (CFPP), Wax Appearance Temperature (WAT), and Wax Disappearance Temperature (WDT). CP indicates the onset of paraffin crystallization, serving as an estimate for operational limits. PP signifies near-complete paraffin crystallization and guides the lowest usable temperature. CFPP indicates filter clogging due to paraffin crystallization, impeding fuel flow.

Each test offers insight into how a fuel behaves in cold conditions. However, methods ISO3015 (visual method) and ASTM D5773 (optical light source) can only be used to measure cloud point when the “petroleum products are transparent in layers 40mm in thickness”. For this reason, VPS researched and developed an “Automatic Test Method for Wax Appearance Temperature of VLSFOs” and published a White Paper on this in 2019.  

VPS Innovative (WAT/WDT) method for Non-Transparent Fuels

The ASTM D5773 method is used to determine the cloud point of clear petroleum products and biodiesels. VPS’s innovation extends this to dark fuels like VLSFO, HFO, and biodiesel blends.

The VPS developed method WAT/WDT test offers a comprehensive view of wax appearance and crystallization temperatures in blended biodiesel with MGO, VLSFO, and HFO. This provides an extensive insight into low-temperature behavior, complementing conventional tests. There’s a correlation between cloud point and WAT, both marking the onset of wax appearance.

Appendix 1 and 2 details some test results of various fuel types identifying the variance in the cold flow properties that are identified by tests in addition to the conventional ISO 8217 tests.

VPS Innovative Gas Chromatography (GC) method for the Biodiesel Impurities in the Fuel Blend

Impurities in biodiesel with FAME, arising from incomplete transesterification of feedstocks, can impact cold flow properties. Elevated total glycerol due to incomplete conversion and glycerol residue can cause issues like injector deposits and clogged systems. These impurities can affect cold weather performance when blended into fuels. Compounds like saturated monoglycerides (SMG) can precipitate above the blend’s cloud point, potentially causing filter plugging. EN 14105 assesses free glycerol and residual glycerides in B100. VPS’s innovative GC method determines mono-, di-, triglycerides, and free glycerol in biodiesel blends with MGO.

Conclusion

The diverse paraffin compositions in biodiesel blends pose challenges in establishing a general cold flow property relationship. These paraffins, from both biofuel and fossil fuel origins, add complexity to the crystallization process. The structural differences between biodiesel and diesel fuel compounds leads to an inconsistent flow behaviour of the blended fuel.

Given the unpredictable nature of low-temperature flow characteristics in blended biodiesel, comprehensive laboratory tests are crucial. Conducting CP, PP, CFPP, WAT/WDT, and GC analysis aids in understanding SMG in MGO blended biodiesel is recommended. Such thorough testing provides valuable insights into the cold flow properties of biodiesel blends.

Note: The full article by VPS accompanied with Appendix 1 and 2 can be found here.

 

Photo credit: Manifold Times
Published: 13 March 2024

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Bunker Fuel Quality

VPS: Importance of fast turnaround times for bunker fuel analysis in today’s market

Thomas Schmidt stressed the growing importance of rapid bunker fuel analysis amid the evolving marine fuels landscape, highlighting how VPS is meeting demand with fast, reliable testing services.

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Thomas Schmidt, Customer Account Manager of marine fuels testing company VPS, on Monday (18 May) highlighted how the company’s rapid, high quality marine fuel quality testing service continue to support the global shipping fleet, through a global network of strategically positioned laboratories, on-line logistics service and over 45 years of experience:

In today’s rapidly evolving marine fuel landscape, fast turnaround times for bunker fuel analysis have never been more critical.

Stricter environmental regulations and wider use of alternative fuels has generated increasingly complex marine fuel types and chemistries. In combination with volatile global supply chains and ongoing geopolitical instability, the need for ship operators and technical managers to have rapid and reliable fuel quality intelligence is increasingly important to protect their vessels, crew, operations, and commercial interests.

Following the introduction of IMO 2020, followed by further global and regional environmental legislation geared towards IMO2030/50, there has been a continuous development of lower-sulphur and low-carbon marine fuels, resulting in fuel quality variability across the global bunker market. Different blend components, cutter stocks, additives and bio-components can result in highly variable fuel behaviour and operational compatibility challenges.

At the same time, geopolitical developments continue to reshape global energy and bunker supply chains. Traditional product flows and refinery sourcing routes are changing, creating additional uncertainty around bunker fuel composition and quality consistency. Notably in 2026, the off-specification rate of fuels to relevant ISO8217 standards increased to 8.5%, from 6.8% during 2025.

Against this backdrop, timely fuel quality testing by an accredited laboratory is essential and remains one of the most effective tools available to ship operators, as advised by all major P&I Clubs. This helps to mitigate operational and financial risk by validating against ISO8217 specifications and providing operational guidance to onboard crew for effective handing and use.

Importance of Speedy Results

Fast turnaround time is critical for several reasons:

  • To assess fuel quality before the fuel is fully consumed onboard. Current fuel off-specification levels are 8.5% i.e. one in every twelve fuels has at least one off-specification parameter.
  • To identify potentially problematic fuels at an early stage.
  • Support fuel segregation, purification, compatibility and handling decisions.
  • Preserve contractual and claim-related rights, including applicable notification and potential time-bar requirements.
  • To reduce the risk of machinery damage, operational interruptions, delays, off-hire situations and costly troubleshooting cases. The Swedish P&I Club stated the average cost of a single marine fuel-related issue is >$330K.

The total turnaround time of a bunker sample is driven by a number of processes beginning with fuel delivery to the vessel and involves multiple critical stages:

  1.   Ensuring the taking of a representative fuel sample, (via a VPS manual drip sampler fitted at the vessel manifold).
  2.   Transfer of the sample to the local agent.
  3.   Sample Transfer via Courier to the laboratory.
  4.   Sample registration and laboratory analysis according to ISO8217 and additional testing requirements.
  5.   Technical review, interpretation and operational advice.
  6.   Report test results and advisory comments.

 

In many cases, the transportation phase alone may consume several days before the sample even arrives at the laboratory. 

How VPS Ensures Faster Turnaround Times

VPS has developed a fully integrated global fuel testing and advisory infrastructure, which currently boasts 93% of samples are reported within one working day from receipt in the laboratory.

SampLogic – Accelerating Sample Logistics to speed up transfer of sample to Lab

The VPS SampLogic platform is an online logistics and tracking solution designed specifically for marine fuel sample transportation, which is free for VPS customers and can save at least one full day on sample transportation. VPS Samplogic

SampLogic enables:

  • Online booking of bunker sample collection.
  • Automated generation of shipping documentation.
  • Shipment tracking and milestone visibility.
  • Faster coordination between vessel, agent, courier and laboratory.
  • By reducing manual processes and improving shipment transparency, SampLogic helps minimise transportation delays and accelerates the overall testing process.

Strategic Global Laboratory Network

VPS operates a global network of wholly-owned, ISO17025 accredited, marine fuel testing laboratories strategically located across the world’s major bunkering hubs in order to support the needs of our shipping customers.

The laboratories positioning further reduces sample transfer times whilst also providing important operational resilience and redundancy. During periods of geopolitical disruption, natural disasters, strikes or unexpected regional events, samples can be redirected within the VPS laboratory network to maintain continuity and avoid delays.

Technical Advisory Support

Analytical results alone are not sufficient in terms of assessing fuel-related operational requirements, fuel management and handling, or environmental compliance. It is the expert and experienced interpretation and advisory guidance which is where the major added-value is delivered to vessels from any fuel testing service.

VPS technical advisors and marine engineers located across the global laboratory network support customers with:

  • Troubleshooting.
  • Fuel management recommendations.
  • Risk assessments.
  • Operational guidance.
  • Dispute and claims support.

Where urgent fuel quality concerns are identified, VPS technical teams proactively contact customers to support immediate operational decision-making, with samples and results able to be progressed at pace, with VPS having supported numerous vessels in providing urgent results in the same working day to meet operational needs.

24/7 Digital Access Through VeriSphere

Through the VPS VeriSphere digital ecosystem, customers have continuous access to:

  • Analytical reports
  • Fuel quality trends
  • Historical fuel data
  • Market intelligence
  • Digital fuel management tools
  • Operational insights

This provides technical managers and vessel operators with rapid access to critical information anytime and anywhere.

In addition, the unique VPS PortStats, MyFuels and MySeparators, on-line applications within Verisphere, can provide deeper insights into global and regional fuel quality and key procurement indicators, plus operational and purifier performance improvements.

Conclusion

In the current climate, bunker fuel analysis is no longer simply a compliance exercise – it is an essential operational and procurement risk management tool.

As marine fuels continue to evolve and global supply chains become increasingly dynamic and unpredictable, rapid and reliable fuel quality intelligence is critical to protecting vessels, machinery, operations and commercial performance.

Minimising the total turnaround time from bunker sampling through to technical advisory support is therefore essential. Through its integrated logistics systems, strategic laboratory network, technical expertise and digital solutions, VPS continues to support the industry with fast, resilient and operationally focused fuel quality services.

 

Photo credit: VPS
Published: 19 May, 2026

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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.

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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

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Bunker Fuel Quality

FOBAS: Estonian shale oil and stability issues found in marine fuels from Singapore

FOBAS released a bulletin stating that tests on several fuels from Singapore identified a chemical fingerprint consistent with Estonian shale oil, while vessels using these fuels reported operational issues.

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Lloyd’s Register Fuel Oil Bunkering Analysis and Advisory Service (FOBAS) on Thursday (7 May) released a bulletin stating that tests on several fuels from Singapore identified a chemical fingerprint consistent with Estonian shale oil, while vessels using these fuels reported operational issues:

In recent weeks FOBAS has tested a number of fuels from Singapore that under detailed chemical analysis with GCMS methods, showed a chemical fingerprint consistent with Estonian shale Oil. 

Shale oil and particularly Estonian shale oil is seen from time to time in fuel blends in certain ports, particularly in Singapore and ARA region. In some of these recent fuels, the estimated concentrations are high, potentially up to 25% of the blend. 

The routine analysis results of these fuels appear on-spec compared to ISO8217 RMG380 grade fuels including Total Sediment results not particularly high.

The vessels using these fuels recently tested with confirmed shale oil are reporting certain operational issues, including excessive sludging throughout the fuel system, blocking of filters and in one case fuel pump issues.

As detailed chemical analysis is not carried out routinely on all fuels, it is difficult to say how many fuels may also have shale oil in the blend. However, from looking at other fuels properties and other supplies from the same barges and suppliers, we can estimate many other vessels have bunkered fuels with varying levels of Shale oil. Not all these ships have yet given operational feedback.

In general, shale oil is often seen as mentioned in certain ports and in many cases, fuels used without problem. However, there is also a long history of fuel stability and sludge related problems related to Estonian shale oil so while it seems not every shale oil blended fuel necessarily will cause a problem there certainly seems an increased risk and in particular in fuels with very high levels of shale oil.

We would suggest requesting from a supplier if shale oil has been used in the fuel blend when bunkering. Also paying particular attention to the Total Sediment results and fuel performance particularly though the purifier. We would also suggest fuels are put into use as soon as possible to quickly identify any potential issues and avoid long term storage.

 

Photo credit: Hans Reniers on Unsplash
Published: 8 May, 2026

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