What is green shipping?

Over the last 30 years, a section of international shipping has made the incredible achievement to reduce fuel consumption and CO₂ emissions by 50 percent. At the same time, they cut NOx emissions by 65 percent.

Green shipping is constantly evolving greener, due to more efficient hulls, lower speed on main engines, higher fuel-efficiency, heat recovery, propeller technology, anti-fouling, improved operations procedures and a series of other innovations that our engineers continuously seek out. Vessels performance monitoring, is a critical tool when assessing the efficiency of our innovations.

The figure below shows five generations of Solvang’s 60,000 cbm class LPG carriers. The data is based on measured fuel consumption, while NOx figures older than TIR I regulation is set to TIR I.

Solvang’s perspective on Green shipping

During the last decades, new environmental regulations have become standard in shipping. From a shipowner´s perspective you either comply, or you die.

Solvang´s strategy is to stay ahead of national and IMO regulations by applying ongoing research to our vessels´ operation. We are part of Smart Maritime, Norwegian Centre for improved energy efficiency and reduced harmful emissions.

All discharges are dealt with according to regulations, and Solvang has disclosed key environmental performance indicators since 2011, on our main webpage. See report here.

AIR SEA SHORE

AIR

Emissions to AIR

CO2: Global warming
SOX: Cloud formation and acid rain
NOX: Cloud formation and acid rain; Ground level ozone
PM: Visible smoke; Health risk
THC: Global warming; Ground level ozone; Health risk
CO: Health risk

SEA

SHORE

Frequently asked questions
about green shipping

What types of fuel can be used in deep sea shipping? What about greenhouse gases? What is HFO? What does HFO contain? Is HFO dirty fuel? How does the metal and sulfur end up in the crude oil?

What types of fuel can be used in deep sea shipping?

All fuels need to comply with NOx and SOx regulations. If the fuel doesn’t comply, then it cannot be used.

Air-emission controls SOx-NOx

What about greenhouse gases?

In the "well to wake" perspective, the only fuels which can potentially reduce CO2 emissions significantly, are biodiesel and biogas.

Presentation: Dr Elizabeth Lindstad October 2018

Until those fuels are available we have to use currently available fuels in the best possible way.

The relationship between CO₂, CO, THC (unburned fuel) and greenhouse gases from NOx Tier III operation show that emissions from HFO operation with scrubber combined with low-pressure EGR (the Solvang Clipper Harald concept), is lower than emissions from dual-fuel lean burn LNG operation.

Utslippene fra HFO-drift med renseteknologi (rødt og grønt) sammenlignet med LNG-utslipp.

Read the SINTEF Marintek report GHG and NOx emissions from gas fuelled engines.

What is HFO?

HFO (heavy fuel oil) is an excellent fuel for ship engines, being the main fuel for world-wide shipping. HFO burns well and the NOx, unburned hydrocarbons (THC) and CO is at the same level as a low-sulfur diesel oil. Due to sulfur contents the particle levels measured in g/kWh are higher, though.

To get an idea of the excellent technical qualities of HFO, we need only to find out how many engine problems are caused by this fuel. The answer is zero - or almost zero.

HFO arises from the lower part of the distillation tower in oil refining. This is a “low-value” product because you need fuel “preparation equipment” before it can be used as an engine fuel. It is a residual substance and the price of HFO is normally lower than that of crude oil.

What does HFO contain?

HFO is a residual fuel, containing sulphur and traces of metals. There is nothing in the HFO which doesn´t originate from the crude oil or the distillation process.

Blending in other components is forbidden according to Marpool fuel standard (Annex VI, regulation 18)

All HFO is tested according to ISO 8216 before it is used.

Is HFO dirty fuel?

HFO is black, it contains sulfur and traces of some metals, but it all originates from the crude oil which again is created by algae. The term dirty fuel is very misleading. HFO is dirty if mishandled or wasted across the sea surface, but for its intended use as ship engine fuel with scrubbing, it is not dirty.

Some critics claim that an open loop scrubber just flushes the dirt from the fuel into the sea. They say this would never be allowed onshore. The fact is that a scrubber via chemistry converts the SOx in the exhaust into sea salt, keeping the HFO clean.

How does the metal and sulfur end up in the crude oil?

Emissions and fuel consumption, newbuilt ethylene carriers, delivered 1978-2019

What does black smoke mean? What is IMO Tier III regulations? How to comply with IMO Tier III regulations? What is sulfur regulation? How to comply with sulfur regulation? What is a seawater scrubber? What about washwater discharge to the sea? What is the requirement for operation of Sea water scrubber? What is Poly Aromatic Hydrocarbons (PAH) ? What is turbidity?

What does black smoke mean?

Publishers usually accompany stories about shipping with a picture of a vessel spewing black hazes from its smokestack. The apparent, yet inadequate conclusion, is to call for cleaner fuel in shipping.

Inadequate because all fuels create smoke if poorly combusted in a diesel engine. Poor combustion may have many reasons, like lack of pre-heating before start, technical issues, bad maintenance, wrong operation or suboptimal engine design. A well-tuned engine in normal operation produces low levels of visible smoke.

If compared, two-stroke slow speed engines emit less smoke than four-stroke medium speed engines. Due to its higher sulfur content, HFO discharges more particles than MGO (distillate marine gasoil) in grams per kWh. But different particle sizes make MGO exhaust more hazardous than HFO to humans.

FSN measurement from HFO operation on M/S Clipper Harald show figures below and/or far below visible smoke under all operational conditions.

Peer-reviewed studies on particles:

HFO and diesel emissions effects on human lung cells…

What is IMO Tier III regulations?

IMO, the United Nations specialized International Maritime Organisation, groups 167 member states. IMO is responsible for The International Convention for the Prevention of Pollution from Ships, MARPOL Annex VI, which limits NOx emissions in ship exhaust.

From Jan 1, 2020, the Tier III NOx emission regulation will set a limit for NOx emissions from new ships.

Marpol Annex VI Tier III limit:

Engine speed less than 130 rpm: 3.4 gNOx/kwh
Engine speed 130-2000 rpm: 9*n^-0.2 gNOx/kwh
Engine speed above 2000 rpm: 2 gNOx/kwh

How to comply with IMO Tier III regulations?

What is sulfur regulation?

IMO regulation for reduction of sulfur emissions:

Outside an ECA established to limit SOx and particulate matter emissions	Inside an ECA established to limit SOx and particulate matter emissions
4.50 % m/m prior to 1 January 2012	1.50 % m/m prior to 1 July 2010
3.50 % m/m on and after 1 January 2012	1.00 % m/m on and after 1 July 2010
0.50 % m/m on and after 1 January 2020*	0.10 % m/m on and after 1 January 2015

How to comply with sulfur regulation?

Option 1: Change fuel to a low-sulfur MGO or 0.5 percent sulfur HFO. All ships can do this without modifications.

Option 2: Install an exhaust gas cleaning system (EGC/scrubber), in order to convert the sulfur in the fuel into sea salt.

Option 3: Have the sulfur removed from the HFO by means of cracking in an oil refinery, resulting in a low-sulfur diesel product. The method is costly and consumes 10-15 percent of the total energy in the HFO. Cracking capacity requires large investments in the refinery, and high opex. The process makes a residual waste called petcoke, which contains the HFO´s sulfur and metals, mainly nickel and vanadium. Petcoke is burnt in power stations or special metallurgical industry, meaning nickel and vanadium still get discharged into the air or sea, unless the power station uses a scrubber.

Option 4: Sulfur cap-compliant fuel can be made by blending HFO with a high proportion of low-sulfur MGO. The method requires more crude oil, and expected higher emissions of CO₂ in the "well to wake" perspective.

What is a seawater scrubber?

The option of complying with sulfur regulations, is by means of “FGD” or the Fluid Gas Desulfurisation process, also called seawater scrubber.

This is a preferred way to remove pollutants from exhaust in coal or oil-fired power stations and other industry with sea water available. The technique utilises the alkanity (mainly calsium carbonate) in sea water to turn sulfur into calcium sulfate.

The current natural concentration of calcium sulfate in sea water is 2,7 g/l. It has been estimated that if all vessels in the world use HFO for another 150 years, the concentration of calcium sulfate will rise to approximately 2,701 g/l. This means a sea water scrubber can be regarded as a reactor converting sulfur into sea salt.

The extra fuel consumption from running an exhaust gas cleaning system is approximately 2-3 percent. This means removing emissions from an HFO-fuelled ship will increase the total CO₂ emissions, either by 10-15 percent if HFO is cracked in a refinery, or by 2-3 percent if done by an on-board scrubber.

Approximately 100 GW of FGD units are currently in operation world-wide, corresponding to 10,000 vessels with 10 MW of installed power.

A sea water exhaust cleaning system (scrubber) normally has an efficiency rate exceeding 98 percent, limiting the NOx emissions to the air to << 0.1 percent. It also removes a considerable part of the soot and other particles, the exact ratio depending on the technical system.

https://youtu.be/drn1vI38qqo

https://youtu.be/-jtTvyxfaiM

What about washwater discharge to the sea?

IMO sets limits to emissions to air and discharges to the sea from exhaust gas cleaning systems (scrubbers). Discharge values are monitored 24/7 and records are kept available for inspection at any time, in addition to chemical wash water analyses.

The rules apply to vessels at bay, requiring PH> 6,5 (6.0 in US) measured four meters from the ship´s side. Verified compliance is part of the vessel´s certification. PAH, turbidity and PH are measured 24/7 upon scrubber operation, and logs must be available for inspections at any time.

As part of Solvang´s scrubber operation on 6 large vessels, three-party water sampling and analyses are being performed in accordance with scientific sampling methods. Done wrong, the sampling results may get very misleading.

When sampling water close to scrubber discharges, a distinction between water treatment systems and non-treatment on scrubber operation must be maintained in order to achieve comparable and reliable figures.

Scrubber Wash water discharge to sea

Exhaust Gas Scrubber Washwater Effluent | United States Environmental Protection Agency

What is the requirement for operation of Sea water scrubber?

A scrubber system needs to be approved by IMO, and the system should be included in the vessel´s IAPP certificates. IMO has set limits on the emissions to air and discharges to the sea.

Those values are monitored 24/7, and records need to be available for compliance inspection at all times. Detailed chemical washwater analyses are also mandatory.

The rules apply to vessels at harbour. Basically it requires water to recover to PH> 6,5 when measured 4 meters from the ship side. Verification of this is a part of the certification process. Operation in US waters requires PH>6 over board.

PAH, turbidity and PH are measured 24/7. Whenever the scrubber is in operation logs should be available.

What is Poly Aromatic Hydrocarbons (PAH) ?

PAH is a part of the unburned fuel in the exhaust. An exhaust gas cleaning system makes sure the major part of the unburned fuel is condensed and caught in the sea water instead of being released into to the atmosphere.

Unburned fuel is denominated as THC (total amount of hydrocarbons), and NMTHC when the methane part of the unburned fuel is excluded. This is important for engines operating on natural gas. In 2015, shipping contributed with 0.5 percent of the total PAH emissions in Norway.

The amount of unburned fuel (THC) from a well-maintained diesel engine operating on HFO or MGO is 0.1-0.2 g/kWh. In comparison, a typical MNHC level from dual fuel engines operating on natural gas, would be 0.4 g/kWh

Report: GHG and NOx emissions from gas fuelled engines | NHO - Næringslivets Hovedorganisasjon

Polysykliske aromatiske hydrokarboner (PAH) | Miljøstatus (NO)

Automotive PAH emissions | Concawe. Environmental science for european refining

Polycyclic Aromatic Hydrocarbons (PAHs) | United States Environmental Protection Agency

A review on polycyclic aromatic hydrocarbons: Source, environmental impact, effect on human health and remediation | ScienceDirect

Polycyclic Aromatic Hydrocarbons | European Commission

What is turbidity?

Turbidity is the measure of relative clarity of a liquid. It is an optical characteristic of water and is an expression of the amount of light that is scattered by material in the water when a light is shined through the water sample. The higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include clay, silt, finely divided inorganic and organic matter, algae, soluble colored organic compounds, and plankton and other microscopic organisms.

IMO regulation states a maximum difference between in and out at 25. On a scrubber this value

Turbidity and Water | USGS.gov

What compounds do we sample? What else do the scrubber water contain? What about nickel and vanadium? What about PEC/PNEC ratio? Scrubber and low-pressure EGR in combination Does scrubbing+EGR boost fuel consumption? What are the pros and cons of using a scrubber? Is it okay to pour dirty fuel into the sea?

What compounds do we sample?

Wash water analyses from properly maintained engines confirm very low level of ∆PAH, scoring less than 10 percent of the requirement. PAH carceniogenics are close to the detection level (below in 5 of 6 tests), and nitrates show close to zero. ∆Turbidity is also less than 10 percent of the limit. The washwater is analyzed according to PEC/PNEC criteria and Norwegian criteria for 9 potential metals, arsen, 16 different PAH components, hydrocarbons from C10-C40, nitrate/nitrite, turbidity and PH, in total 35 different components.

The results show PH close to levels in coffee, the washwater is rated as non-toxic for all components, and above good for 19 of the components. PAH carciogenics score on or below detection levels in 5 out of 6 samples. The PAH values for fenantren, fluoranten and pyren are higher than in water of good quality, but far below poor quality.

(Link to Marintek report MT2016 F-152, "Clipper Harald operation with scrubber")

Link to paper Meeting future emission regulation at sea by combining low‑pressure EGR and seawater scrubbing

What else do the scrubber water contain?

IMO requires the following analysis.

APPENDIX III

WASHWATER DATA COLLECTION

This sampling could be made during approval testing or shortly after commissioning and at about twelve-month intervals for a period of two years of operation (minimum of three samples).

Sampling guidance and analysis should be undertaken by laboratories using EPA or ISO test procedures for the following parameters (link to IMO report in pdf):

Ph
PAH and oil (detailed GC-MS analysis)
Nitrate
Nitrite
Cd
Cu
Ni
Pb
Zn
As
Cr
V

What about nickel and vanadium?

Heavy metals nickel and vanadium are main components needed to be considered in more detail.

Vanadium is a regular part of sea water in concentrations 0.9-2.5 µg/l, as vanadium is constantly fed into the nature in the range 0.6 million tonnes/year from bedrock. Vanadium is not a hazard due to low toxicity. The amount of vanadium released from HFO from shipping can be estimated to 0.045 million tonnes (225 million tonnes HFO averaging 200 mg/kg fuel, against 1,368,000,000 km³ sea water). This gives a yearly supply of 0.000033 µg vanadium/l seawater, amounting to an increase of 0.1-0.4 percent concentration over a hundred years of unrestricted HFO operation.

Nickel is another normal part of sea water in concentrations of 1.7 µg/l). Nickel is constantly fed into sea water from bedrock. Discharges from HFO operation in shipping have been estimated to 50 mg nickel/kg HFO. When applying the same calculation as with vanadium, we reach an average supply of 0.0000082 µg/l each year, or an increase in nickel levels of 0.05 percent over a 100 years.

What about PEC/PNEC ratio?

An analysis of the predicted effect (PEC) and no-effect concentration (PNEC) is a standard environmental risk assessment concerning chemicals. When applied to a sampling of sea water close to the scrubber washwater outlet, combined with a simulation, the results show similar PEC/PNEC figures 3-6 meters from the outlet. Accordingly, washwater discharges do not affect the surrounding water at this distance or likely anywhere beyond.

The results above are in line with the conclusion in the Danish Environmental project 1431, Assessments of possible effect of scrubber water discharge on the marine environment. (Download report here in pdf).

An obvious conclusion to the above, if any doubt about the water quality in a specific sensitive harbour area, is that detailed analyses could be carried out to verify water quality.

Read the paper Meeting future emission regulation at sea by combining low‑pressure EGR and seawater scrubbing

(Link to Marintek report MT2016 F-152, "Clipper Harald operation with scrubber")

Scrubber and low-pressure EGR in combination

Not all environmental challenges can be solved in one go. Greener shipping must be a collected outcome of many techniques and actions of which exhaust gas cleaning is one.

By combining seawater exhaust gas cleaning (scrubber), with exhaust gas recirculation (EGR), Clipper Harald (12,600 cbm gas tanker built in 1999) has operated for three years below TIR III NOx levels using HFO as fuel.

The test program also includes third-party washwater analysis and emission measurement. The figure below shows the historical NOx figures for the vessel.

Does scrubbing+EGR boost fuel consumption?

Definitely not.

A combination of those two techniques achieves an environmental and cost-effective solution to SOx and NOx compliance, which in the perspective "from well to propel" gives low CO2 emissions.

TIR III compliance without any use of urea and catalyst is attractive from a cost point of view, as urea consumes 10 percent of the fuel. The use of urea also adds CO2 to the total CO2 footprint from shipping.

Additional fuel consumption for scrubber operation is 2-3 percent and if you already have invested in a suitable scrubber, the additional cost for the LP-EGR equipment is minor.

The additional fuel consumption for SOx reduction below 0.5 percent is also minimal. The scrubber solution will normally give SOx <0.05 percent world wide (i.e similar to ultra-low sulphur fuel or LNG).

The additional fuel cost for running TIR III is minor and as expected (2-3 percent). The combined systems are installed on four 21,000 cbm ethylene carriers and 80,000 cbm gas tankers which have been delivered in 2019. The figure below shows the historical environmental performance, where the fuel consumption is reduced with appr. 60 percent, NOx and particles with appr. 90 percent, while the SOx is reduced with 99.8 percent. The massive improvements come as a result of 40 years of dedicated efforts from the shipowner, yards and equipment suppliers.

What are the pros and cons of using a scrubber?

Pros:

Lower CO2 emissions in a "well to propel” perspective

SOx close to LNG levels.

Good use of a low-value, low-cost product from the oil refinery.

Engines already fit for using HFO.

When combined with LP-EGR, a very cost-effective solution where the cheap fuel also pays for the NOx cleaning.

The scrubber catches a considerable part of other toxic particles in addition to the MGO particles.

Combined with a new concept which is under development and called ECO-EGR, TIR II NOx operation with EGR.

Cons:

High investment cost.

Nickel and vanadium accumulation in special enclosed harbour areas.

Is it okay to pour dirty fuel into the sea?

This and similar questions are often posed towards shipowners. As we work systematically and knowledge-based in cooperation with some of the world´s most renowned scientists, environmental authorities and our own suppliers in order to reduce the environmental impact of shipping, it is sometimes confusing or even frustrating to answer such questions in a serious way.

Please refer to our comprehensive research performed through (a.o.) the Smart Maritime centre for research-based innovation (follow this link to learn more).

The simple answer to the question, is of course NO. IMO regulations stipulate clear conditions for operating a scrubber, and the certification process involves flag state, class society and IMO authorities.

From a shipowner´s perspective it should be ok to earn money, but nobody should pollute more than absolutely necessary in order to transport goods around the world.

In principle, the lower cost of HFO pays for both SOx and NOx cleaning.

The figure shows the relationship between CO₂, THC (unburned fuel) and greenhouse gases from NOx Tier III operation. Emissions from HFO operation with scrubber is proved to be lower than the much acclaimed Lean Burn Dual Fuel LNG emissions.

Which leads to our conclusion:

The question about pollution is not which fuel you use, but how you use it.

Emission has been gauged by research institute Sintef Ocean (formerly Marintek)

Read the SINTEF Marintek report GHG and NOx emissions from gas fuelled engines.

Read the article Meeting future emission regulation at sea by combining low‑pressure EGR and seawater scrubbing.

Read the report Emission measurements on main engine on Clipper EOS during TIER III certification

Articles

Years of evolution has made HFO-fuelled shipping greener

Shipping today is much greener than 30 years ago, a development that will continue. At the same time, this is an evolution, not a revolution.

Making heavy fuel oil clean

Exhaust gas recirculation (EGR) combined with previous measures reduce NOx emissions from heavy fuel oil by up to 80 percent in a typical LPG tanker.

Scrubber Wash water discharge to sea

A scrubber system needs to be approved by IMO, and the system has to be included in the vessel´s IAPP certificates. IMO has set limits to the emissions to air and discharges to the sea.

HFO in line with green shipping

After three years of testing, Norwegian scientists prove HFO with correct technology complies with IMO´s Tier III emission regime and new SOx regulations. That could turn sentiment in favour of the mocked but ingenious fuel.

The evolution continues

Solvang´s new class of ethylene carriers are the first HFO-fuelled TIR III compliant ethylene carriers in the world. The vessels´ specification and detailed design are based on previous ECO design combining cost-effective means to minimize overall fuel consumption.

How to comply with 2020 regulations

In practical terms, most ships can exchange propellants for more expensive low-sulphur MGO or low-sulphur HFO, without the need for modifications. Or you can install a scrubber and keep running on a cheaper, more engine-friendly and more energy-efficient fuel.

Solvang’s perspective on Green shipping

Frequently asked questions about green shipping

Emissions and fuel consumption, newbuilt ethylene carriers, delivered 1978-2019

Articles

Years of evolution has made HFO-fuelled shipping greener

Making heavy fuel oil clean

Scrubber Wash water discharge to sea

HFO in line with green shipping

The evolution continues

How to comply with 2020 regulations

Frequently asked questions
about green shipping