Reducing harmful emissions during lay days
The Hamburg Port Authority (HPA) has commissioned Siemens to build a turnkey onshore power supply at the Hamburg Altona cruise terminal. The system will supply electricity to cruise ships of all common sizes and electrical system designs, allowing them to turn off their own diesel generators and reduce harmful emissions during their lay days.
The first European onshore power supply system of this type has a capacity of 12 megavolt amperes (MVA) and works with a patented, mobile robot arm designed specifically for the tidal range. The heart of the system is a frequency converter with control software that adjusts the frequency of the local distribution grid to the ship's electrical system. The scope of supply for Siemens, in its capacity as general contractor, includes the medium and low voltage switchgears, the transformers, the fire safety system and the building's air conditioning and ventilation system. Commissioning is scheduled for the spring of 2015. The order volume will run to around 8.5 million.
The onshore power supply system from Siemens meets the required international standards IEC/ISO/IEEE 80005-1 (cable connection between shore and ship on the medium voltage side) and IEC 62613-2 (connectors and sockets). The modular system from Siemens covers all power ranges required in the shipping industry and is suitable for the world's common ship frequencies (50 and 60 Hertz) as well as all necessary voltage levels for shipping. Voltages of 6 or 10 kilovolts (kV) are provided in the 50-Hertz range and 6.6 or 11 kV in the 60-Hertz range. In principle, for example, 50 Hertz AC current is converted to 60 Hertz AC current during frequency conversion. In the Siemens system, two converters are therefore connected to back to back by a DC link, and each converter is connected to the onshore and onboard converter transformers. As a result, the system is able not only to power an isolated network from a distribution grid but to harmonize power supply grids having different parameters and to connect them to each other. Siemens uses a multi-level converter on the ship facing side onshore, which guarantees a harmonic-free alternating current characteristic. Converter transformers are used to connect the system to the supply grid. The transformer on the ship facing side ensures galvanic isolation between the ship and shore grids, as required by IEC 80005-1.
The system has a specially developed cable management system for cruise ships that provides a fast, easy and flexible connection between the shore and the ship. The system is self-propelled and can be automatically operated from the ship as needed, so that no additional specialists are needed on shore. A concrete channel along the quay wall guides a high tide-resistant cable chain for system mobility and is designed with a length of 300 meters for this project. A robot arm is used to transport the power cable connectors and the communication link into the ship through the outer hatch, like on a tray.
Developed jointly between Siemens and Stemmann Technik in Schüttorf, this technology also compensates for the tidal range during power supply. Power is transferred to the ship without slip rings, making it immune to dysfunction. The concrete channel's steel plate cover can easily support the required axle loads, so that telescoping cranes, trucks and buses can drive over the quay operating area with no restrictions during the lay days. The cable management system is stored in a high tide-protected garage when not in operation, thus meeting the Hanseatic City of Hamburg's requirement for granting visitors public access to wharfage.
One of the main causes of local air pollution in ports is the combustion of ship fuels for generating electricity during lay days. Reducing harmful emissions due to shipping is a concern in port cities around the world. For more than ten years now, the European Commission has recommended, through regulations, incentives and access facilitation, that port authorities provide ways for ships to use onshore power sources during lay days in port. This recommendation was last specified and expanded in 2006. In 2013, the European Commission also drew up a proposal for a directive on "Deployment of alternative fuels infrastructure." According to this proposal, the greenhouse gas emissions caused by traffic must be lowered by 60 percent by 2050. Alternatives such as electricity at berths and liquefied natural gas (LNG) during transport are gaining in importance in seaports. According to Article 4 of the proposal, the member states are to ensure that an onshore power supply for ships is provided in most seaports and inland harbors.
Source and Image Credit: Siemens