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.

Read more about Smart Maritime´s work package Power systems and fuel.

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.


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

Frequently asked questions
about green shipping 

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?
What is HFO?
What does HFO contain?
Is HFO dirty fuel?
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?

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.

Read more: Years of evolution has made HFO fuelled shipping greener

Peer-reviewed studies on particles:

  1. HFO and diesel emissions effects on human lung cells…
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 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?
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?

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


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.

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