Though the “self-installing” moniker might be slightly misleading, European researchers have announced the development of an offshore wind turbine which can be completely pre-assembled and pre-commissioned in controlled harbour conditions before being towed to its offshore location.
Researchers with the European Union’s Community Research and Development Information Service (CORDIS) working on the ELISA project have developed an “innovative” offshore wind turbine construction process which uses a gravity-based foundation combined with a telescoping tower complete with wind turbine. The offshore wind turbine system can be completely pre-assembled and pre-commissioned in controlled harbour conditions before being towed to its open-water site using conventional tugboats, where the platform is then secured to the seabed and the turbine tower raised.
“The ELISA technology is a pioneer in the development of completely self-installing offshore turbines,” said project engineer José Serna. “The entire system is completely pre-assembled and pre-commissioned in controlled harbour conditions, enhancing the possibilities for industrialisation and minimising risks related to offshore assembly work.”
This new process erases the need for costly and rare heavy-lift vessels, which in traditional offshore wind projects are the only way to build the offshore wind turbine in situ.
“It’s important to note that currently there are only three or four heavy-lift vessels in Europe capable of installing an 8 MW turbine in waters deeper than 40 meters –and Europe leads the way in comparison to other developed markets,” exlpained Serna. “In other words, this system will also be a key European export to such markets as the US and Japan.’
The ELISA project was designed “to develop and demonstrate in operative environment a full scale prototype of a revolutionary substructure system for offshore wind turbines” which would consist of “a self-installing precast concrete telescopic tower which for the first time ever shall allow for crane-free offshore installation of foundations, towers and turbines, thus overcoming the constraints imposed by the dependence on offshore heavy-lift vessels.” The ELISA project constructed a 5 MW prototype which was installed and currently located in the Canary Islands.
“ELISA will allow for drastic cost reductions in the substructure supply and in the installation costs of offshore wind energy, which is set to play a strategic role in Europe’s evolution towards a low-carbon and locally sourced energy mix,” said Serna. “As a matter of fact, the cost per MW of the prototype being developed is already below current market prices, despite all the investment required in auxiliary infrastructure and means whose complete costs have been dedicated to a single unit.”