11/18/2015 The Motorship - Exhaust gas cleaning – solutions for sulphur oxide emission reduction

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Exhaust gas cleaning – solutions for sulphur oxide emissionreduction25 Mar 2014With tighter SOx regulations in ECAs coming intoeffect in 2015, shipowners and operators mustdecide within the next few months on how to reduceSOx emissions; Leonardo Sonzio, director retrofit,Wärtsilä Ship Power environmental solutions,explains that there are two main options, exhaustgas cleaning systems or switching to lower sulphurcontent fuel.

By the end of 2013, Wärtsilä had 41 vessels contractedfor a total of 88 exhaust gas cleaning (scrubber)systems, for both newbuild and retrofit projects. Wärtsilähas accrued about 70,000–80,000 running hours with itsopen loop scrubber system, and around 6,000 runninghours with its closed loop scrubber. The majority of therunning hours have been accumulated at sea as well asat the Wärtsilä test facility in Moss, Norway.

Wartsila considers that this experience puts it in an informed position to share practical insights into the prosand cons of investing in such a system.

SHIP TYPE AND GEOGRAPHY

Wärtsilä calculates that if, for example, a large vessel sails roughly 50% of its time in ECAs, investment in anexhaust gas cleaning system is a solid business case. In the case of a vessel with large installed power, thereis a positive business case even if the vessel sails less than half of its time in ECAs. The best return oninvestment is usually achieved in a ro­ro or ferry operating in ECA. Ro­ros and ferries typically have highengine power and hence, rather high absolute annual fuel oil consumption. In addition, they are used in shortsea shipping, which means they are operating within an ECA practically 100% of the time – if located in theECA.

In addition, bulkers, tankers and containers operating 30% to 40% of their time in ECAs benefit from anexhaust gas cleaning system because they also consume vast amounts of fuel oil. Wärtsilä says that bulkers,tankers and smaller containers are quite straightforward from a retrofit point of view and, hence, less costly.This improves the total economics of the investment.

In the end, the return on investment depends on various factors, such as total installation time and downtime,operating costs of the exhaust gas cleaning system, and expectations of future fuel prices.

According to Wärtsilä, the biggest cost factors in exhaust gas cleaning retrofits are the equipment, theinstallation, operations and material. Generally, the cost of the equipment varies depending on the type andsize of the ship. The installation cost depends on the extent of modifications to the existing ship, and the timeneeded at the dry dock.

“Usually, equipment and installation each represent 40% of the total price for a turnkey retrofit; the remaining20% is related to engineering, project management, site management, logistics and class approval costs,” saysMr Sonzio.

An alternative to installing exhaust gas cleaning systems would be switching to lower sulphur content fuel suchas MGO or LNG. Wärtsilä estimates that because of growing demand for marine gas oil caused by SOxregulation, the price difference of MGO and HFO would be expected to increase in 2015. So, the true expenseof using MGO versus HFO in the future is uncertain. The other low sulphur option is LNG which is said to bethe cleanest fossil fuel and is currently the fastest growing fuel type in the world. However, switching to LNGrequires changing the engine.

OPERATIONAL FLEXIBILITY

Wärtsilä has delivered exhaust gas cleaning systems to many companies who have already made repeatorders after initial experience with their first systems installations. Some of those companies include Solvang,Wilh. Wilhelmsen and Ignazio Messina.

Clipper Quito and Clipper Victory (Solvang)

11/18/2015 The Motorship - Exhaust gas cleaning – solutions for sulphur oxide emission reduction

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Norwegian operator Solvang considered an exhaust gas cleaning system the only realistic option for itsenvironmentally friendly LPG carriers, such as Clipper Quito and Clipper Posh. MGO, with the market price andindirect changeover costs, was seen as a rather expensive alternative. LNG is not, for the time being, an optionfor Solvang’s existing fleet due to lack of infrastructure and regular sailing patterns.

Tor Øyvind Ask, fleet director of Solvang ASA explained: “Given a total evaluation including environmentalperformance and operational cost and flexibility, exhaust gas cleaning is the best solution for us. HFO isavailable all over the world, which gives us maximum fuel capacity and operational flexibility. Clipper Posh ison a long term time charter and will sail in and out of the ECAs. The cost reduction inside those areas isestimated to be around US$20,000 per day.”

Solvang now has four operational scrubber systems in two vessels. The company has ordered exhaust gascleaning systems from Wärtsilä for six further vessels. The first delivery was in 2013 when a Solvang’snewbuilding was fitted with two open loop scrubber systems.

“Our two vessels with Wärtsilä’s exhaust gas cleaning systems have been in normal operation; Clipper Quitosince July and Clipper Posh since December. Both vessels have been sailing inside and outside of ECAs. Wehave now accumulated about 2,000 running hours with good experiences,” says Mr Ask.

According to Solvang, scrubber system installations have been technically quite unproblematic. Getting therequired class approvals, on the other hand, has taken longer than expected with testing and reports. After thepaperwork was completed for Clipper Quito, subsequent approvals became easier. Clipper Posh was the firstship in the world to obtain a full term IAPP (International Air Pollution Prevention) certificate on exhaust gascleaning.

“We believe that exhaust gas cleaning brings us competitive edge. Our LPG carriers are cheaper to operate inECAs due to lower fuel cost; the scrubber systems are one of many actions, which are carried out to improveour environmental performance and reduce fuel consumption. We see exhaust gas cleaning as a way forwardto us,” Mr Ask concludes.

DIFFERENT SOLUTIONS

There is a possibility that ECAs might expand at some point. Therefore, reduced sulphur emissions are on theagenda for shipowners planning to build new vessels. Provision for exhaust gas cleaning system fitting at theship design phase should save cost compared with retrofitting.

Retrofitting scrubber systems may pose some challenges, but they can be overcome. “In retrofit cases, findingspace for the system is the most common challenge. Sometimes there is a need to make changes in the funnelshape or rethink the use of spaces in the vessel to create more room for scrubber systems. So far, we have notcome across any project in which retrofitting would not be technically possible. It is just a matter of identifyingthe best solution or compromise with the shipowner,” Mr Sonzio explains.

The Wärtsilä portfolio of exhaust gas cleaning systems includes three configurations for removing sulphurcontent from the exhaust gas: open loop scrubbers, closed loop scrubbers, and hybrid scrubber systems. Allthree configurations include a wash water treatment plant to clean the effluents before discharge into the seawith no risk of harm to the environment. In addition, the closed loop scrubber and hybrid scrubber can beoperated in a zero effluent discharge mode for a certain period of time, if required.

The closed loop system uses freshwater and a reagent, typically caustic soda (NaOH), and works best in seaswith low alkalinity and for operators looking for zero discharge. The open loop system, on the other hand, is thepreferred option for ocean­going ships because it uses seawater, and neither freshwater nor caustic soda isneeded. The hybrid scrubber systems operate on either open loop or closed loop by using sea water, and seawater and caustic soda respectively. This allows for full flexibility of operations. The hybrid systems sail both inseas with low alkalinity as well as in open oceans. It is also possible to first install an open loop system and, ifneeded later, modify it for hybrid operation.

“Factors affecting the choice of an exhaust gas cleaning system – or not choosing one – are mainly the shiptype and size, its absolute annual fuel consumption and the vessel’s geographical operating area. Choosing anopen loop or closed loop scrubber system depends on where the vessel sails in. Some vessels require fullflexibility due to their vast sailing range. Equipped with an exhaust gas cleaning system, a vessel can operateon HFO inside and outside of ECAs. Hybrid technology increases flexibility even more,” Mr Sonzio concludes.

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11/18/2015 The Motorship - Exhaust gas cleaning – solutions for sulphur oxide emission reduction

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