The challenge of expanding the grid and technical innovations
The focus of the main conference day was on grid development, technical developments in plant construction and hidden success factors in plant operation.
The day began with a conversation between Irina Lucke, Managing Director of EWE Offshore Service & Solutions GmbH and Chairwoman of the wind energy network WAB e. V., and Holger Matthiesen, Project Director for Offshore Wind Pre Construction (Germany/Denmark) with E.ON Climate & Renewables, on the subject of “10 years of offshore wind in Germany – a retrospective on a successful history?”.
“German efforts in the offshore wind sector are a success story. Automation has advanced considerably. Current projects are already much more successful than they were even in the days of Alpha Ventus. A lot has been learned the hard way since then. Alpha Ventus was painstakingly planned and implemented with great attention to detail and is therefore very reliable. Today, there are many more error sources, even if overall maintenance costs have been reduced. This is due to the fact that access to turbines has been greatly improved and also that we have better equipment and vehicles. The standardisation of processes is also improving efficiency. At a technical level, plants with a capacity of 10 MW are not the limit. Limiting factors in construction and maintenance need to scale up and adapt to the new size. However, growth on its own is not the deciding factor, better quality and reliability would be equally desirable.”
“Installation times are becoming shorter and shorter. Recently, we were able to install 60 wind energy plants in three months. Noise minimisation is a serious issue for us: the bubble curtain is now established as the new standard for protecting marine mammals. At Arkona, the largest offshore wind farm in the Baltic Sea, we remain significantly below the required values. The discharge of metal into the water has also been reduced by applying an aluminium alloy to the monopiles. Maintenance times are another major economic factor but progress has also been made in this area. In addition to capital costs, maintenance costs account for one-third of the price of an offshore wind turbine. The trend shows that electrical substations are also decreasing in size and becoming more standardised.”
The following agenda item, entitled “The grid – a key to success?!”, focused on the electricity grid and grid connection.
Dr. Ursula Prall
Dr Ursula Prall, Chairwoman of the German Offshore Wind Energy Foundation asked how much offshore the grid could take. She supported both the expansion and optimisation of the grid. She added, however, that the energy landscape needed to change fundamentally. Time was running out for the energy transition to succeed.“ Dynamic line rating, phase-shifting transformers and online assistance systems should be used to guarantee grid stability. We present this in the grid study conducted by the offshore associations.”
Dr. Athanasios Krontiris
Dr Athanasios Krontiris, Product Manager HVDC at ABB, reported on the offshore HVDC systems, which to date have only been deployed in Germany (North Sea) and are responsible for the high-voltage direct-current transmission of electricity from offshore wind farms to land. Developing connection stations could result in material savings of 50%. He is currently working on the hybrid interconnectors that connect the national grid areas to better exploit the infrastructure, which in turn could help to reduce costs. The current project is the offshore wind farm, Kriegers Flak, on which Germany, Denmark and Sweden are collaborating. “The grid is the key to success in offshore wind power. National plans are reaching their limits. Constructive development of the European framework is in the interest of all stakeholders,” Krontiris said.
Jean Huby, Managing Director of Ocean Breeze, shared his experience of the failed wind power company BARD Engineering GmbH with the plenary assembly. A major problem with the construction and operation of plants was that the compatibility of the components had not been checked. This meant, for example, that obsolete software was used in the control system. In conclusion, he admitted that wind energy plants rapidly aged due to technical development and therefore the prompt maintenance of subcomponents had to be guaranteed.