Part of Germany’s energy future lies in the water. According to government targets, offshore wind energy will cover 15% of the country’s electricity demand by 2030. At least 5,000 wind turbines at sea are necessary to meet this goal. Twenty-nine projects have already been approved and others are in the permitting phase, with most of the facilities being built in the North Sea. The Alpha Ventus pilot wind farm already supplies electricity, and construction of the first commercial wind farm has started.
Large components such as tower segments, nacelles, rotor blades and, in particular, foundation structures have dimensions that require barrier-free access to the port. High transportation and cargo handling costs — alongside their need to be readily available for installation — make it sensible for offshore wind energy to set up production plants in immediate proximity to the port. It also requires the logistics procedures of production to be networked to the port. Efficient and transparent planning of all logistics processes and costs can help make wind energy more competitive.
Efforts in this direction have been successfully made in Germany’s northern port of Bremerhaven, where turbine makers Areva Wind and Repower Systems, foundations specialist WeserWind and blade supplier PowerBlades have all set up production facilities. The 12 turbines for Germany’s first offshore wind farm, the 60MW Alpha Ventus project, were manufactured here. The port was equipped with heavy-load quays and new industrial space was created right next to it.
Port and logistics areas have also opened up in the northern part of the city. The state of Bremen is planning an additional offshore terminal and is currently improving the infrastructure needed to develop more industrial space. Through their full commitment to offshore wind energy, the state of Bremen and the city of Bremerhaven have created more than 3,000 jobs in manufacturing, research and training, and port operations and logistics.
The offshore wind sector has realised that a holistic approach to logistics is necessary to exploit the full development potential of wind energy. Cooperation between those involved along the value chain to generate offshore wind power at competitive costs also requires new and integrated IT solutions.
A joint project involving BLG Logistics Group, the Bremer Institut für Produktion und Logistik and construction group Hochtief Solutions, entitled Mon2Sea and funded by the German environment ministry, is aiming to support the production and logistics processes related to industrial-scale production and the construction of offshore wind-energy facilities.
Key to this is the development of an IT research platform to enable real-time monitoring of wind-turbine components all the way to installation at sea. The objective is to generate automatic status and position messages for the components and comprehensive process checks at a central control station.
As a global logistics service provider, BLG can combine its know-how on port operations with experience in procurement, production and distribution logistics to co-ordinate and manage the chain from procurement to production through to offshore installation, carrying operational responsibility at all levels. This expanded range of services, from engineering, through assembly assistance to quality-assurance measures enhances the efficiency of the supply chain and reduces costs.
The company has invested in a specially developed pontoon named Offshore BHV 1, which is capable of transporting the 900-tonne and up to 60-metre high foundation structures for offshore turbines. A rail system has been developed specifically for loading and discharging. The new vessel is 70 metres long, 32 metres wide and has a load capacity of 8,000 tonnes.
The pontoon can reach sites anywhere in the North and Baltic Seas. It has 17 ballast tanks and a redundant pump system with a capacity of 1,200 cubic metres per hour. Aside from the unique rail solution for cargo handling, a completely new sea fastening system has been devised to secure the large, heavy foundation structures on board. This means the time-consuming process of welding heavy loads — and the just as work-intensive separation at destination — is no longer necessary.
At the moment, the pontoon is transporting foundation structures from manufacturers WeserWind in Bremerhaven’s Fischereihafen and SIAG in Emden, to the BLG offshore terminal in Bremerhaven. In each case two tripods are carried on electro-hydraulic bogies via the tracks from production directly onto the pontoon with integrated rails and are secured using the sea fastening system. The pump system ensures that the height of the pontoon’s loading platform is always kept at the height of the quay. On the offshore terminal, the foundation structures roll ashore again on rails. This unique process eliminates the need for a crane for loading and unloading the pontoon.
At the terminal, the tripods are taken to their storage sites by self-propelled modular transporters (SPMTs), which can be coupled to one another as desired. On the offshore terminal three SPMTs carry one leg each of a tripod.
Travelling speed and all manoeuvres are controlled in parallel. No cranes are used for storage and provision of the tripods for the installation vessel either. Only when the tripods are loaded onto the installation vessel is the crane of the jack-up vessel deployed.
This procedure illustrates how cooperation between production and logistics provider can lead to new holistic solutions, shorten processes and save costs.
Hartmut Schwerdtfeger is spokesman for BLG Logistics Group AG & Co KG