The prospect of offshore floating wind turbines was at the center of a series of studies at the Offshore Technology Conference that examined the future of the nascent technology.
The primary concern was stability and structural integrity of a turbine floating in open water, where wind resources are strong and have great potential for power production.
Researchers are considering a variety of floating designs that could be based on a floating tripod structure, a semisubmersible base inspired by offshore oil and gas platform designs, or a long column, or spar, design that is often used on oil platforms.
Currently, two substantial demonstration projects of floating turbines are being tested in Europe.
Much of the research focused on basic questions that have not been fully answered, such as the difference in bending of wind towers when they are floating, changes in their stability or power efficiency based on designs. Researchers are also trying to figure out how challenging environmental conditions could impact a turbine at sea.
All of the presentations were of particular interest to contractor Gregory Matzat, who focuses on offshore wind technology for the U.S. Department of Energy.
“Europe has a head start on us, but we see a lot of potential here,” Matzat told the audience.
The department plans to offer $180 million in grants for five innovative offshore wind projects over the next few years, he said. Technology developed through grants and other research will help push the country toward its goal of 54 gigawatts of power generation from offshore wind turbines by 2030.
One gigawatt of electricity can power hundreds of thousands of homes.
However, researchers say many questions still need to be answered before the U.S. can reach its goal.
The complications of possible hurricane-force winds and varying wave patterns will still require research when considering different floating designs and geographies, said Qing Yu, an engineer for ABS Corporate Technology.
Modeling to gauge stresses on offshore turbines, whether they are floating or installed into the seafloor, is also still developing, said Huimin Song, a researcher at the National Renewable Energy Laboratory.
Demonstration turbines have performed well, however, and they have shown that they can withstand offshore environments, said Christian Cermelli, co-founder of Marine Innovation & Technology, who gave a presentation on a floating 2 megawatt turbine off the coast of Portugal.
“The short-term viability of an offshore wind farm was proven,” Cermelli said of the demonstration project, which produced 1 gigawatt of energy over six months.
Some in the audience raised questions about the cost of the Portugal turbine. Cermelli would not comment on the project cost, but he said the project was expensive because it was a demonstration using new technology and methods.
“I am quite sure that we will achieve a level where we can actually make money out of floating offshore wind,” he said.
The world’s first floating offshore turbine was part of a nearly $70 million project from Norwegian energy company Statoil to develop between a pilot program of between three and five turbines. The 2.3 megawatt Hywind turbine has operated during testing for two years and “it continually performs beyond expectations,” Statoil spokesman Ola Morten Aanestad said in an email.
“With few operational challenges, excellent production output, and well-functioning technical systems the Hywind concept could revolutionize the future of offshore wind,” he said.