Led by Spanish researchers and engineers, the ELISA project has developed a new offshore wind turbine system that can be completely pre-assembled and pre-commissioned in controlled harbor conditions, effectively eliminating the need for cranes or heavy-lift vessels.
According to the European Commission, the costs of installing the necessary turbines have always been an obstacle to its widespread adoption of wind energy – and this is especially true for offshore wind farms, which require large, high-tech wind turbines to be constructed and maintained in the oceans themselves.
Thanks to the ELISA technology 5 MW fully operational prototype, this traditional barrier to the use of wind energy has been overcome. The prototype is located in the Canary Islands and is the first bottom-fixed offshore wind turbine completely installed without the need for costly and scarce heavy-lift vessels, according to the commission.
“The entire system is completely pre-assembled and pre-commissioned in controlled harbour conditions, enhancing the possibilities for industrialization and minimizing risks related to offshore assembly work,” says project engineer José Serna.
The ELISA 5 MW prototype features a gravity-based foundation, an automatically telescoping tower and a wind turbine.
Once tugged into its out-at-sea position, the platform is ballasted to rest on the seabed. Then, when secure, the tower is lifted to its final position via cables and conventional heavy-lift strand jacks. These jacks start by lifting one level of the tower and then are reused to lift the next level.
“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,” says Serna. “In other words, this system will also be a key European export to such markets as the U.S. and Japan.
“This vessel-free installation capacity is not only a source of large cost reductions, but also a way to support the clear trend towards larger offshore wind turbines, a key step towards improving a wind farm’s cost of energy,” explains Serna.
According to Serna, the ELISA system can reduce costs by as much as 30% to 40% compared with traditional solutions based on jackets or XL monopiles and can also save users on maintenance and upkeep.
Photo courtesy of ELISA