The scrubber option versus the LNG option

A growing number of countries and regions around the world are introducing bans on open loop scrubbers that use seawater in the exhaust cleaning process.

What are the ambitions behind the bans, what are the consequences for stakeholders along the entire value chain, and what are the options?

Yara Marine Technologies R&D manager, Shyam Thapa examines the facts behind the debate: “Some studies have shown that open loop bans have no real environmental impact, while others maintain that the effects of wash water on marine life have yet to be assessed or may even be harmful.”

Regardless, he said, there are different reasons for enacting bans. Open loop scrubbers do not perform effectively in water with low alkalinity, such as rivers and inland waterways.

“In these areas, systems supplying alkali in a closed loop are required, so open loop bans are largely formalities.”

Some private ports are also enacting open loop bans, but Thapa said that this may often be for reasons other than environmental concerns.

He believed that a combination of ‘want to’ and ‘need to’ is a likely future scenario on open loop scrubber bans, with flexibility being the common key to ensuring compliance and unrestricted operations.

Yara Marine manufactures both open and closed loop exhaust scrubber systems, and hybrid scrubbers capable of operating in either mode depending on applicable geographical regulations. “Open loop is still viable for 80-90% of global marine transport,” Thapa claimed. “Our estimates for hybrid solutions assume maximum 15% of operation time using closed loop mode. But if the vessel is operating in waters where open loop is forbidden, owners either need to be able to operate the scrubber in closed mode or switch over to alternative fuel.”

Scrubber smart

For those still pondering their options, Thapa is sympathetic. “I think the main thing is to emphasize that the overall picture is more complex than what is presented in the media.

There are many factors in the calculation, and each case is different. There is no blanket solution for every situation.”

He noted that vessel specific considerations and trading profiles will determine the choice of solution for many, venturing that the spread of open loop bans could influence more owners to choose hybrid solutions in order to ensure flexible operations for the life of the vessel.

Thapa claimed that those choosing Yara Marine will benefit from a simple, light and efficient solution. The company’s in-line system has no internal moving parts, and Yara’s magnesium oxide technology is cheaper to operate and maintain and safer than systems requiring caustic soda.

International research continues into the effects of scrubber wash water discharge to the sea. Several major ship owners have been collecting data from their fleets as well, and all will have to be considered before consensus can be reached on the ultimate consequence of open loop scrubbers for marine environments.

Yara is involved in an ongoing research project with Chalmers University of Technology to combine SOx and NOx gas cleaning in a single system. The project is also investigating possible industrial uses for exhaust sludge. The results could be applicable for both marine and land-based applications, giving the project wider environmental significance.

The company is also working intensively to solve the issue of particulate matter (PM) from combustion processes. The goal is to reduce harmful PM smaller than 2.5 micron by more than 95%.

Yara Marine Technologies CEO, Peter Strandberg, would like to see further investigation into scrubber options, supported by more hard facts: “We want to see more independent research to move the debate forward, and we invite owners and operators who are uncertain about the best scrubber solution for them to contact us. With our flexible technology, Yara Marine can help owners and operators comply, whatever the abatement requirement.”

LNG as a fuel

One of the champions of the use of LNG as a fuel is the Sovcomflot Group (SCF). At the Digital Ship - Vessel Performance Optimization (VPO) Forum held in Limassol, Cyprus last month, Dr Oleg Kalinin, SCF Management Services’ fleet director gave an outline of the company’s involvement in utilizing LNG for part of its tanker fleet.

He explained that SCF had taken delivery of four out of eight LNG powered Aframaxes ordered from Hyundai Samho and latterly at Zvezda and had ordered another three LNG fueled MRs at Zvezda.

The vessels form part of SCF’s ‘Green Funnel’ operation whereby ships use LNG as the primary fuel source.

He said that accepting there are more than 2,500 vessels fitted with scrubbers, this equates to around 10-15% of of the total fuel consumption with the result that the remainder of the fleet will have to burn IMO 2020 compliant fuels.

The challenges of running on LNG depend on the vessel design and performance, safety, shore staff and seafarer training, operations and maintenance, the infrastructure and capital costs.

On the Aframaxes, SCF opted for WinGD X-DF 7x62DF low-speed dual-fuel propulsion units with low-pressure gas injection. They are rated at 13,800 kW at 86 rev/min each giving a service speed of 14.6 knots. The daily fuel consumption is 42.3 tonnes when operating in Tier II fuel oil mode, or 34.7 tonnes daily when burning gas.

For bunkering, SCF is involved in a joint industry initiative with Shell and is participating in a Shell working group to develop LNG bunkering procedures and manuals.

As a result, SCF’s quality and safety management system bunkering procedures have been amended. The company has also requested Shell to ask OCIMF to amend the SIRE VIQ for vetting purposes, Dr Kalinin said.

He pointed out that SCF has been operating DFDE powered vessels since 2014 and there are currently eight in the fleet, mainly LNG carriers. Ships’ engineers from the LNGC pool are helping engineers on board the new Aframaxes with gas fuel operations.

Extra training

Additional training is also undertaken at the OEMs’ premises, at the shipyard and in-house, making use of the St Petersburg SFC Training Centre, as well as on board the ships.

He said that there were more than 100 ports worldwide with either LNG bunkering infrastructure in place or planning to fit facilities.

The Aframaxes are designed principally to trade between Northern Europe and the Baltic and have an Ice Class 1A Hull notation.

Maintenance and repairs can be undertaken in the region, for example, at Blohm + Voss and Remontowa.

Port discounts are available for LNG powered vessels, for example Antwerp is offering 15% discount for LNG fuelled ships, plus 20% of those fitted with closed loop scrubbers.

Rotterdam is also offering a similar package for LNG fuelled ships with a Green Award certificate.

Dr Kalinin said that the higher capital costs involved in fitting LNG fuel equipment on board could be offset by lower opex brought about by cheaper bunker costs from the Shell co-operation deal. At present, the Aframaxes are being bunkered from Gate Terminal in Rotterdam or the Baltic using Shell’s bunkering vessel ‘Cardissa’.

He said that lower opex and shorter returns on investment will drive LNG market penetration, as soon as ship operators face higher distillate costs.