Background

Hong Kong's Kwai Tsing container port plays a major role in Hong Kong's economy, handling roughly 220 million tonnes of goods yearly. As a key hub for trade between China and the rest of the world, the port handles trans-shipment materials and merchandise bound for the mainland and, in return, serves as an export centre for Chinese goods to the rest of the world.

There is a strong business case, in addition to the port's economic benefits and social responsibility to address air quality issue in the surrounding area.

As Hong Kong's largest port operator, Hongkong International Terminals (HIT) is taking the initiative to explore various ways to help improve air quality and the overall environment at Kwai Tsing port.


Cleaning up the Problem

At its facilities at Kwai Tsing Container Terminals 4, 6, 7, 9 and 8 East (through a joint-venture with COSCO-Pacific), HIT has a quay length of 4.6 km for 14 ship berths and up to nine barge berths that are served by 52 Quay Cranes (QCs), four Rail-Mounted Jib Cranes and one Harbour Crane. Adjacent container storage is handled by 24 Rail-Mounted Gantry Cranes (RMGCs), 140 Rubber-Tyred Gantry Cranes (RTGCs) and 12 Bridge Cranes (BCs).

Diesel is the common fuel used at the container port. In particular, the terminal operators of Kwai Tsing have been using – thanks to an exemption granted by the Hong Kong Government – an Industrial Grade Diesel (IDO) which contains a higher percentage of sulphur than motoring diesel.

Each year, the average consumption of a container port operator reaches 15 million litres of IDO to power the RTGCs alone. When internal trucks, site vehicles, front loaders and reach stackers are added to the picture, the quantity of IDO used is much larger. IDO has a direct impact on the environment in terms of emissions.

Other yard equipment such as QCs and RMGCs are electricity-powered equipment and do not consume IDO. To improve the level of emission from port equipment, HIT conducted a series of investigations and pilot projects to determine the feasibility of converting RTGCs' fuel source from diesel to main electricity.


Electrification

HIT embarked on identifying opportunities to use electricity as a substitute for powering the RTGCs in its premises at Kwai Tsing. This measure does not only reduce emissions from RTGCs substantially, it also offers cost benefits in the long term.

A survey conducted among seven ports of Hutchison Port Holdings (HPH) explains that the cost of electricity per container move is just around one-quarter of that of diesel.

HIT took the initiative to test electric power systems in selected RTGCs at its premises at Kwai Tsing. The options included a cable reel system and a ground conductor bar system at the terminal.

When implementing the options, major considerations for the electrification of the RTGCs included:

• Terminal layout – allowing sufficient space between the RTGCs and the width of RTGC legs, containers and operating blocks
  
• Civil works – such as the availability of cable ducts and draw pits, and the civil concrete and asphalt design
  
• Operational flexibility – interruptions during installations and moving RTGCs from block to block
  

Test runs were implemented on four fixed blocks involving two RTGCs, one using a cable reel system and one using a conductor bar system as a prototype for different design concepts. A fixed conductor bar system was finally selected. Installation in 17 RTGCs is to be completed within 2007.

The major benefit of replacing diesel with electricity on RTGCs would be savings of up to 70 per cent on fuel, 80 per cent on engine maintenance costs, elimination of black smoke and noise pollution, and extended maintenance intervals.

In additional, based on the capital costs of constructing a conductor bar system, HIT calculated that the cost payback of using electricity instead of diesel would be realized in three to four years. However, the benefits to the environment are invaluable.


Energy Efficiency

Apart from the electrification test run of the RTGCs, HIT has also explored other initiatives to improve energy efficiency in RTGCs:

1. Self-supply of Energy

• Super Capacitor
  
  The Super Capacitor is a means of capturing expended power from the RTGCs and returning it into the system. As much as 20 per cent of lost energy can be recovered. This is a common technology used in transport vehicles. The principle is shown below:
  
  
  
  
• Lithium-ion Battery
  
  Instead of using a Super Capacitor, which is still not very reliable, a lithium-ion battery was used. The system configuration is the same as Super Capacitor except for the addition of a voltage stabilizer (i.e. a DC/DC converter) between the lithium-ion battery and the DC bus. Installation of this system was carried out on one unit in August 2007 and that unit is now being tested.
  
  It is expected that a 26 per cent in diesel consumption savings per container move will be achieved.
  

2. Energy Saving from Speed Adjustment

• Variable Speed Engine
  
  The version used by HIT is based on a variable speed diesel engine provided by General Electric. This effectively adjusts the speed to match the load demand by regulating the air-to-fuel ratio.
  
  Additional features, such as an electronic fuel injection system and a waste gated turbocharger, are included. The design principle is shown below:
  
  
  
  
  A test run on one RTGC has been implemented. The results indicate energy savings of up to 30 per cent. Some fine-tuning is still underway.
  
  
  
• Diesel Engine Speed Reduction
  
  As fuel consumption is approximately proportional to engine running speed, a reduction in engine speed from the existing 1,800rpm (60Hz) to 1,500rpm (50Hz) can save as much as 15 per cent on fuel consumption without adverse effects on operational productivity. When combined with fine-tuning of the main hoist acceleration time and full speed, 20 per cent of total fuel savings is achievable.
  
  Although some electromagnetic components have to be replaced to meet the new 50Hz frequency, it is justifiable to implement it when the short payback period is taken into account. A saving of around 10 per cent to 15 per cent in fuel consumption is expected.
  
  HIT is planning to modify all 77 RTGCs by the end of 2007.
  
  In addition, HIT is set out to switch, over a two-year period, from Industrial Diesel Fuel (IDO, 0.5 per cent sulphur) to more expensive Ultra-low Sulphur Diesel (ULSD, 0.005 per cent sulphur) for all its RTGCs, internal tractors and container yard vehicles. This will contribute to better air quality around the Kwai Tsing port as the level of sulphur dioxide emissions will be significantly reduced.
  
  
  Other Initiatives
  
  HIT has implemented other energy-saving initiatives and will continue to explore other means to reduce air pollution. These include:
  
  
• Floodlights – replacing electromagnetic ballasts with electronic ballasts, using double filaments and applying auto-switch-off quay crane boom floodlights when boom up
  
• Use of shore power for vessels during berthing – “Cold-ironing”
  
• Use of “CombustAll” – a fuel-borne catalyst to reduce emission
  
• Solar power for traffic lights and water heating
  
  
  
  

Conclusions

As one of the main port operators at Kwai Tsing, HIT has taken the initiative to improve the air quality of the surrounding area. The success of the electrification programme to reduce diesel consumption, and hence improving air quality, has been proven. As a result, HIT is extending the programme to other port equipment and vehicles. Use of Super Capacitors, lithium-ion batteries, variable speed engines and lower diesel engine speeds will supplement this initiative to achieve energy and cost savings while reducing emission and maintaining the flexibility of terminal operations.

There are two clear opportunities for HIT:

The technologies are also transferable to other HPH ports. As a result, these initiatives not only make economic sense but also provide a sound environmental argument for HPH to replicate the success of HIT's initiatives in its worldwide network of ports.

Furthermore, the other container terminal operators in Kwai Tsing may adopt similar technologies. HIT is prepared to work closely with the Hong Kong Container Terminal Operators Association and other terminal operators to create an industry platform through which techniques could be shared to generate economies of scale as well as significant improvements in air quality.