Slow steaming
Slow steaming is a strategy of reducing fuel costs in liner shipping ( container shipping ) that was previously only pursued by tankers or bulk carriers . Reduced fuel costs with slow steaming are offset by longer travel times, which can be It may have to be compensated for by using more ships. This increases the capital commitment for the shipping company as well as for the suppliers and customers. When weighing up capital, adherence to delivery times and energy costs, the latter play an increasingly important role in container traffic.
causes
While the fuel requirements of newbuildings in container shipping continued to rise until around the year 2000, the cruising speed of tankers and bulk carriers has been reduced to up to 11 knots for a long time due to the lower cargo value per ton and the less critical delivery dates . By 2008, the average fuel cost for container ships had increased seven times the cost of 2000. With a 10,000 TEU ship, the fuel costs amount to approx. 45% of the total costs. Their share increases with the size of the ship. Lubricant costs for the largest engines alone can run to $ 800,000 a year. As a result of this cost explosion and the financial and associated shipping crisis in 2008, the slow steaming strategy also found its way into liner shipping. In the short term, it led to cost savings and a reduction in capacity due to longer travel times.
technical realization
drive
The slow-steaming concept is especially in the mainly used in the liner shipping ships with low-speed two-stroke - marine diesel engines used. A reduction in machine performance to around 50% is generally considered to be unproblematic from a technical point of view. However, when the engine load is lower, the dwell time of the lubricating oil in the cylinder increases while the cylinder temperature decreases. If the exhaust gas temperature is less than 250 degrees Celsius, the sulfurous acid formed by the oxidation of the sulfur contained condenses when the dew point is below the temperature . This means that more iron particles can accumulate in the cylinder drain oil. Therefore, diesel oil with a low sulfur content or lubricating oil with a higher base number (70–80 KOH / g) should be used.
Instead of mechanical cylinder lubrication, electronically controlled lubrication is used in part-load operation, which creates a thin but sufficient lubricating film, with which over a third of the lubricant can be saved. In 2010, the Wärtsilä shipyard supplied the Maersk shipping company with 34 retrofit packages for the electronic optimization of engine lubrication in continuous low-load operation.
The reduced exhaust gas flows during slow operation also reduce the boost pressure disproportionately in engines with turbochargers . Here, too, technical adjustments are necessary. B. necessary by shutting down individual chargers in multi-charger systems or by reducing the size of the turbocharger.
Hull shape
The savings are particularly great if the ships (including the hull shape) have been designed for slow steaming from the start, as was the case for the first time in 2011 at the Hyundai- built Maersk Conakry with 4500 TEU . The hull becomes shorter and wider, which means that less ballast water has to be carried. Because of the lower speed, the propeller diameter increases and the bulbous bow must also be optimized. The shape of the hull of the ships can also be adapted to slow travel. At speeds around 15 knots, the frictional resistance in the water plays a greater role than the wave breakage resistance. Therefore, a straight stern is used more often , as is known from classic ocean liners.
In addition, experiments are being carried out with underwater air bubble carpets to reduce water resistance, which were first used in the Aida ships of the Hyperion class .
Slow steaming also increases the incentive to use ocean currents and tides through route optimization.
Economic and ecological effects
By deliberately slowing down and scrapping less energy-efficient ships, it was also possible to dampen excess capacities in container shipping. Since the upturn in 2010, there have even been bottlenecks in individual segments. Because more and more ships were entering the market, slow steaming increased the cost pressure on older and smaller ships that had to move into niches or be laid up.
Another side effect is the shortage and increase in cost of rental containers due to longer turnaround times. Between 2009 and 2012 the capacity utilization of the leasing container park at large providers increased from approx. 85 to approx. 95%, so that some investors invested more in funds for loan containers than in ship funds. However, there was speculative hype and sometimes investment fraud.
The ecological consequences are clearly assessed as positive. By reducing the amount of fuel used, emissions are also reduced. In addition to the emission of carbon dioxide , sulfur and nitrogen oxides - in conjunction with the use of suitable lubricants - the metallic impurities contained in the heavy oil , which are bound to its highly condensed aromatic compounds, are reduced.
However, ballast journeys in slow steaming operation are less economical than journeys with cargo, so that a higher machine capacity should be provided than is already necessary for safety reasons. This reduces the possible positive ecological effect.
Some analyzes predict the loss of importance of shipping due to the reduced speed on short distances and its replacement by trucks and trains. That could also reduce the ecological effect. However, electric locomotives are increasingly being used in rail freight transport and the proportion of renewable energies in the traction current network is increasing.
Examples
The Germanischer Lloyd calculated that on the Hamburg-Shanghai in a container ship that took 26 knots fast is only 18 knots, the fuel consumption of 6,210 to 3,700 tons falls - a savings of 40%. If the speed is reduced to 12 knots, the savings effect is even 50%.
In the crisis year of 2009, the Maersk shipping company reduced the standard speed of its container ships from 24 to 12 knots. In 2010, this saved 20% fuel. Maersk attributed the return to profitability in 2010 to slow steaming.
The slow speed also increases the reliability of adherence to delivery dates, as the previously tightly calculated timetables were often disrupted by unforeseen events. For this, the customer may need to slightly increase the stocks in buffer stores.
Also Hapag-Lloyd went to the slow travel concept over and retains it in even after the end of the crisis. However, the slow speed, against which many marine engineers initially expressed technical concerns, requires improved cleaning of the turbochargers and increased maintenance of the valves. Since 2009 a turbocharger has been removed from each of the ship's engines in order to reduce their output. Instead, the charge pressure of the remaining turbochargers increased.
The Hamburg-Süd put the speed of their ships in Latin America service from 20 to 16 knots down and reported 40% fuel savings. The turnaround time of the ships increased from six to seven weeks, which meant that another ship had to be used.
Maersk's Triple E-Class ships , which were the largest container ship type in 2014, are designed for an optimal speed of 19 knots. The fuel savings compared to the maximum speed of 25 knots should be 20% at a speed of 22.5 knots, 37% at 20 knots and 50% at 17.5 knots. The ships are to serve the Europe-China line, the journey time from China via the Suez Canal to the Netherlands is to be 23 days.
As ultra-slow steaming is called lowering the speed to seven or even five knots. Bureau Veritas and Wärtsilä , in cooperation with other partners, carried out a pilot project from 2011–2013 , which was funded in the 7th Research Framework Program of the EU and assumed a recommended speed of 5 knots for 2050. However, at these speeds the maneuverability of the ship decreases.
Legal Aspects
In 2012/2013 the first successful lawsuit by a charter company for breach of contract was brought against a ship owner who had reduced the speed of his ships. Most contracts, however, release the carrier from any responsibility for meeting deadlines. In 2011, the BIMCO shipping association developed contract variants that are intended to regulate the permissibility of slow steaming between charterers and ship owners.
Alternatives
Retrofitting the Trans-Siberian Railway for mass container traffic between East Asia and Europe does not seem ecologically sensible under the current framework conditions. It is also problematic from an economic point of view, since the containers at the Russian or Chinese border have to be moved from standard gauge to broad gauge and back again and since the rail and network operating costs in Siberia are very high with limited capacities. According to ICOMOD, the trade flows between East Asia and Europe by rail will double from 2009 to 2030 to 1 million TEU (standard container). Currently, however, sea transport is growing much faster (at around 10% per year), while only less than 5% of freight traffic from East Asia to Europe is handled by rail.
Individual evidence
- ^ C. Ferrari, A. Tei, F. Parola: Facing the economic crisis by cutting costs: The impact of low-steaming on container shipping networks . Paper presented at International Association of Maritime Economists (IAME) Conference, Taipei, Taiwan, September 5-8, 2012, in: http://www.porteconomics.gr/news/assoc-members-news/item/359-the-impact -of-slow-steaming-on-container-shipping-networks.html
- ↑ a b Container shipping half speed ahead . Süddeutsche Zeitung , May 30, 2011
- ↑ fh-flensburg.de (PDF) accessed on January 30, 2014
- ↑ High base number prevents cold corrosion , Schiff & Hafen, 65 (2013), volume 12, p. 30
- ↑ Bernd Maienschein: Wärtsilä receives major order from Maersk for 34 slow steaming upgrade kit packages . MM Logistik, Vogel Business Media; Retrieved April 26, 2013
- ^ Port Technology, March 28, 2011
- ↑ containership-info.com
- ↑ Franz Neumayer: AIDAprima: Details on the vertical bow and pod drive , October 10, 2013, cruisetricks.de
- ↑ Angelika Hillmer: New technology: ships slide over carpets made of air bubbles. In: welt.de . July 9, 2012, accessed October 7, 2018 .
- ↑ At half speed , Logistik heute, 7-8 / 2010
- ↑ message. ( Memento from February 4, 2014 in the Internet Archive ; PDF) In: Hafenwirtschaft No. 12 (2012) based on a report by DVZ ( Deutsche Logistik-Zeitung )
- ↑ Greenpeace Magazine , October 26, 2010
- ↑ Slow Steaming - The full story . ( Memento of November 2, 2012 in the Internet Archive ; PDF; 9.7 MB) Maersk; Retrieved April 26, 2013
- ^ Schiffstechnik ( Memento from December 31, 2010 in the Internet Archive ) , Hapag-Lloyd; Retrieved April 26, 2013
- ↑ Saving emissions ( memento of November 3, 2012 in the Internet Archive ) , MAN press release on the 2012 shipping fair; Retrieved April 27, 2013
- ↑ Slow Steaming - Less fuel, less CO2 ... if you drive slowly enough ( Memento from April 27, 2014 in the Internet Archive ) , Hamburg Süd; Retrieved April 26, 2013
- ↑ PDF file at www.metrans.org ( Memento from October 2, 2013 in the Internet Archive ), accessed on September 9, 2014.
- ^ Project page for the Triple E class ( Memento from September 10, 2014 in the Internet Archive ), accessed on September 9, 2014.
- ^ Website of the Ultra Slow Ships project (ULYSSES) ; accessed on June 11, 2020.
- ^ Gavin van Marle, Container ship owners could be sued for slow steaming . The Loadstar, Jan. 28, 2013; Retrieved May 14, 2013
- ↑ Harilaos N. Psaraftis (Technical University of Athens), The economic and environmental dimensions of slow-steaming . Lecture (2012), martrans.org (PDF)
- ↑ ICOMOD: Eurasian Railway Initiative stimulated ( Memento from August 26, 2014 in the Internet Archive )
- ↑ Russians plan broad gauge to Vienna . Verkehrsrundschau, June 8, 2012