Image: DNV GL

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The Exhaust Gas Cleaning Systems Association (EGCSA) says a recent survey of its members has revealed that the number of vessels with exhaust gas cleaning systems (EGCSs), or scrubbers, installed or on order, jumped to 983 as of May 31, 2018, whilst the total number of scrubber towers was up to 1561.

Bulk carriers the top vessel type

Of the scrubbers installed or on order, 28 percent are for bulk carriers; 23 percent for tankers; 16 percent for container ships; 15 percent for cruise ships; and 13 percent for ro-ro/short sea vessels/ferries.

Most installations are retrofits

The number of ships retrofitted with scrubbers amounts to 615, or 62.6 percent, which comprises 463 vessels with open-loop installations and 152 with hybrid systems fitted.

Newbuild ships with scrubbers fitted add up to 368, or 37.4 percent of the total, with 220 ships choosing open-loop scrubbers and 148 opting for hybrid.

Of the 1561 scrubber towers installed or on order, 1014 (697 open loop and 317 hybrid), or 65.0 percent, were retrofits and 547 (291 open loop and 256 hybrid), or 35.0 percent, for newbuilds.

Open loop the most popular scrubber type

Overall, the number of ships with open-loop installations is 683, or 69.3 percent of the total, whilst those with hybrid systems add up to 300, or 30.5 percent.

The total number of open-loop and hybrid scrubbers installed is 988 (63.3 percent) and 573 (36.7 percent) respectively - confirming open loop as the most popular exhaust gas cleaning system.

Commenting on the data, the EGCSA said it was "not surprised" that open loop was the preferred option. "It is the simplest scrubbing system and favoured by ship crews. Although many early adopters in the North Sea and Baltic fitted hybrid systems, they are operated for the majority of time in open loop. Open-loop scrubbing has also been used for years by coastal power stations and by oil tanker inert gas (IG) systems when in port without environmental issues"

"While closed-loop and hybrid systems are available for enclosed bodies of water with little water exchange or where discharges are restricted by local regulation, ECGSA suggests the alternative of switching to low-sulphur fuel for the port stay where open-loop operation is not possible. The cost impact is likely to be limited as over 90 percent of fuel consumption is during full away at sea, which is where the financial benefits really accrue," the EGCSA noted.

Asia gets lion's share of installations

The survey shows that 59 percent of all scrubber installations (for both retrofits and newbuilds) take place in Asian yards. This number rises to nearly 85 percent for newbuild projects.

Europe has 28 percent of all scrubber fittings, and North America 8 percent.

Jump in largest engine power

The EGCSA notes that, until quite recently, the largest-capacity scrubbers installed had been for engine powers in the region of 25 megawatts (MW) to 30 MW. However, the latest data shows that this figure has been well and truly beaten by a retrofitted hybrid system for a 72-MW container ship engine.

The largest power engine for a retrofit open-loop scrubber system is 70 MW.

In terms of newbuilds, a hybrid system for a 65-MW engine tops the list - showing that large-capacity scrubbers are not just confined to retrofits.

And the biggest power engine for a newbuild open-loop scrubber system is now 50 MW.

Yard capacity 'not an issue'

The EGCSA posits that even though there has been a surge in demand for scrubber installations, yard capacity is "not an issue" going forward. However, constraints such as the availability of experienced installation teams and laser scanning specialists mean that it may not be possible to pick and choose an installation slot nor coincide a scrubber installation with an already-scheduled drydock in the near future, the association said.