Tired of Talking Green: No Go on Scrubbers

Discussing maritime technology - without the marketing clichés

Op-Ed by Wendy Laursen

James Ashworth, a lead consultant for Singapore-based business consultancy TRI-ZEN is a proponent of LNG. Why? The alternatives just aren’t economically viable, he says: “Exhaust gas scrubbers face huge challenges. People talk about retrofitting them to existing vessels, but available space makes this impossible in most cases. The scrubber itself is a large piece of equipment and when you add in multiple pumps and tanks the total additional space requirement is substantial.”

Scrubbers add around three percent to a vessel’s fuel consumption. The additional power requirement for electric pumps is beyond the scope of most vessels’ designed generation capacity, so fitting an additional generator will often be required, pushing up costs and pressure on space further.

And that is not the end of the problem. Arguably NOx is a greater threat to health than SOx, and new regulations will control these emissions vigorously. NOx abatement is still required with the use of ultra-low sulphur diesel. NOx is abated by reacting the hot exhaust gases with ammonia or urea in the presence of a catalyst. The cost of ammonia and urea has doubled in recent years and is set to continue rising, adding further cost. None of this is required when burning LNG.

The problem is compounded even further in that proof of compliance with emissions legislation using non-compliant fuels requires continuous monitoring and recording of the exhaust gas emissions using highly sensitive equipment that requires tight calibration and expert staff, the cost of which runs into millions of dollars and none of which has yet been developed for marine use. LNG meets all current and future planned legislation and requires no exhaust gas treatment or monitoring.

So the financial arguments for scrubbers and NOx reactor retrofits and newbuilds are weak, says Ashworth: “Even if you could install them on board, you are looking at little or no cost advantage over equipping a ship to burn LNG. With oil getting more difficult and expensive to produce and increasing onshore and offshore gas availability, the price of oil is predicted to drift further from that of gas. You are really left with the choice of buying increasingly expensive low-sulphur diesel to operate in ECAs or to go to LNG.” In the US, LNG is currently about half the cost of heavy fuel oil. “To me, LNG is a no-brainer.”

LNG Terminals Map

Some detractors have raised safety concerns about the widespread use of LNG but this has no rational basis, says Ashworth. All energy sources have some hazard association. LNG is entirely predictable, relatively difficult to ignite and causes no oil spills. Methane disperses in air and, unlike liquid fuels and LPG, does not flow into drains or bilges and explode spectacularly when ignited.

Others have complained that the raft of new emissions legislation is inappropriate at a time when shipping in general is sailing through troubled waters. The problem is that the industry has been complacent, and the effects of globalization have served to make shipping the fastest growing emitter of greenhouse gases in the transportation sector. “Time to pay the price. The hubris put out by the detractors from legislation is strangely reminiscent of that spouted by the tobacco industry when it was pointed out that smoking might actually kill you,” says Ashworth.

There are around 60+ LNG-fuelled vessels in service today with double that number on order, mostly concentrated around Norway, the Baltic and North Sea. To go global, a new world of marine LNG storage and distribution infrastructure is waiting to be developed, says Ashworth. Initially, it is likely that some sharing with existing LNG import infrastructure may be possible, but that too is not without challenges. “Whilst there are pretty pictures, nobody has yet built an LNG bunker barge. And if/when LNG becomes a mainstream marine fuel, it will more than double the current global LNG production demand. Investors, take note!”

Current estimates indicate 250 years of LNG supply. “We are witnessing the end of the oil era and the beginning of the gas era. Potential demand has expanded rapidly from 167 million tons in 2005 to 280 million tons today.” The diagram below shows the broad span of LNG infrastructure planned and in place.

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If you would like to propose viewpoints or topics for future articles in this series, please contact Wendy Laursen at [email protected].