Siemens Gamesa is aiming to cut the cost of offshore wind foundations by up to 30 percent as part of a project unveiled this month.
The turbine maker said it was working with Aalborg University of Copenhagen, Denmark, on a five-year offshore wind cost reduction project called i4Offshore, which is being funded by the European Union to the tune of €20 million (USD $23 million).
The centerpiece of the project will be the development of a 1,000-ton gravity jacket foundation design that Siemens Gamesa Renewable Energy has already tested in Danish waters.
The concept will feature a concrete transition piece and will sit on lightweight suction buckets, which could minimize the submarine noise of turbine installations by doing away with the need for monopile hammering.
A further benefit could come in decommissioning, said Jesper Moeller, project lead and senior specialist in offshore technologies at Siemens Gamesa’s offshore business unit in a press release .
“Once the wind turbine has exhausted its many years of operational life, the suction buckets, jacket foundation and transition piece can be decommissioned and removed relatively easily,” he said.
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“The materials, including steel, concrete and cables, can be re-used in a highly resource-efficient manner.”
Siemens Gamesa executives believe the design stands a good chance of beating the cost of monopile foundations, which are used for around four out of five offshore wind turbines today. The company is targeting a 20 percent to 30 percent reduction on the 2015 cost of monopiles.
The jacket design could potentially work better than monopiles with larger turbines and deeper waters, both of which are trends in the offshore wind industry.
It could also be easier to make the jackets in emerging markets where there is currently no monopile manufacturing supply chain to support the offshore wind industry.
In the U.S., Deepwater Wind’s pioneering Block Island offshore project used jacket foundations made by Louisiana-based Gulf Island Fabrication as an alternative to bringing monopiles all the way from Europe. Asian offshore markets could also be served with jackets.
While the primary focus of i4Offshore work will be to develop a competitor to monopiles, Siemens Gamesa is also hoping to get monopile makers stoked up about coming up with better, cheaper designs.
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Foundations can account for between around 15 percent and 20 percent of the capital cost of an offshore wind project, so any reduction would have a big impact on the industry.
Apart from foundations, the tie-up with Aalborg University will also be targeting other areas of potential cost reduction. One that offers short-term promise is to use plastic sheaths for onshore cables, as opposed to having complex steel reinforced cables as is currently the case.
Siemens Gamesa has already tested the concept with a single-core cable as part of a Danish demonstration project and will be looking to extend the technique to multi-core cables within i4Offshore.
The company believes the work could deliver a 20 percent to 30 percent reduction on typical 2017 cable costs.
However, the overall impact on project costs would be lower than a new foundation design because the electrical infrastructure of a wind farm accounts for less of the total cost, about 10 percent to 15 percent.
Siemens Gamesa picked Aalborg University for the i4Offshore project because of the university’s track record in working with suction bucket foundations.
More than a dozen other organizations are also involved in the project, including the cable maker NKT, the jacket assembly specialist Bladt, the installation firm Fred Olsen and Bureau Veritas, the certification company.
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Siemens Gamesa is due to start talking to customers in the New Year about possible North Sea locations for a test site.
Rob Bates, an offshore wind risk specialist underwriter at the insurance company GCube, said: “With the growth of the sector, reducing levels of risk from cable lay and foundation failure will be key to ensuring stable energy production and a lower levelized cost of energy.
“While, typically, industry experience results in lowered levels of risk as challenges are identified and overcome, R&D projects such as Siemens' i4Offshore project have the chance to accelerate this process, pooling knowledge of how best to mitigate risk.”