Justin Martino, Associate Editor, Power Engineering
April 02, 2014 | 7 Comments
The needs of offshore wind production require different solutions than onshore, Fisas-Camanes said.
"From the Alstom perspective, we see two different worlds," he said. "Onshore has some contraints, and they are not the same constraints you are going to see in an offshore site. We are treating them as two different animals, and we are using different technologies for those two applications."
The use of different technologies for onshore and offshore wind power projects is another change that has occurred over the past 10 years. While companies used to take the same wind turbine used on land and installed it offshore, but Fisas-Camanes said Alstom took a different approach with its current generation of offshore wind turbines.
"If you look at the new generation of offshore wind turbines, our wind turbine, the Haliade 150, has been designed from the very beginning to operate in offshore conditions," he said. "This has driven different aspects of the design of the wind turbine, with one of the main decisions being using direct drive technology."
The Haliade 150 is a 6-MW turbine that uses a 150-meter rotor. Fisas-Camanes said the company plans to continue developing and investing in the improvement of the direct drive solution for its offshore wind turbines, including improving its efficiency and weight.
Companies are also looking at the use of floating wind turbines, which use floating structures instead of requiring wind towers be set into a foundation under water.
"Ten years ago, it was hard to imagine floating wind turbines, and this is real now," Fisas-Camanes said. "We're in a demonstration phase right now, and I'm expecting to see the development of floating wind farms in the next 10 years."
As companies look to make more sophisticated wind turbine technology, more sophisticated tools are required. One of those is 3D modeling technology, which allows companies to use computer simulations to see how products will respond before manufacturing and testing the product in the field.
Alstom's Haliade 150 turbine was designed from the beginning for use in offshore wind production, resulting in different solutions being used than the company uses in its onshore wind turbines. Photo credit: Alstom
Tools to Improve Efficiency
"Maybe five or 10 years ago, people would put a wind turbine behind a tractor trailer, drive at 60 miles per hour and measure what the velocities would be on it," said Ahmad Haidari of ANSYS, a company that produces simulation software. "Imagine having all that on the computer, where you can change the angle of the attack, change the velocity and change the yaw angle."
Computer simulation can be useful to companies as they look to increase the capacity factor of turbines. The software allows companies to help design blades that allows for attached flow across a range of flow velocity without having to continuously make the rotors larger, Haidari said.
Companies are able to use software to create a virtual lab and set up the blade in the lab. Designers can then vary the blade geometry, blade twist, yaw angle, angles of wind attack and wind velocities. The simulations will allow designers to see the coefficient of lift and drag across the blade on both the top and bottom surface.
"In wind turbine blades, blades could be very thin at the end, and there's also a little twist to it, so maintaining fluid dynamic contact on the blade across of range of wind velocities and different angles of attack and different yaw is a complex fluid mechanics problem," he said. "Once we have the rotor size as large as we can, the next thing is, 'How can we get the blade efficiencies up?' That means fluid dynamic efficiency across a range of wind speeds."
Modeling software can be used in more than blade design, however. Haidari said software can be used when siting wind power projects. Buildings, hills and even trees can change wind turbine behavior, so using software can help choose the correct installation for a given wind farm. Although siting may be less important in offshore wind power projects, the software can be used to help decide the best way to run power onshore as well as determine on the right strategy for installing the tower into the ocean floor.
The technology can be used for a variety of other simulations, including manufacturing components, as well as monitoring the potential performance of generators and components, performing structural analysis or looking at electronic controllers.
"When you look at wind blades, you have to look at the whole system," Haidari said. "Looking at the blade is part of it, but one needs to look at the entire system design in order to have a full understanding of the blade's performance. Everything, including your washing machine, is becoming more sophisticated. Designing these around a single component doesn't help."
The Future Focus on Innovation
The technological advances made with wind turbines have resulted in clear bottom line: Wind power is more efficient and affordable than it has ever been, which has helped drive its popularity along with power prices and incentives such as the U.S. production tax credit. Also, Fisas-Camanes said wind power has proven itself as a good option for companies looking for power that can come online quickly.
"It's a fast track technology, it doesn't need water and it doesn't pollute the earth, so it's an easy and quick energy solution for increased generation," he said. "I think there are a number of reasons, technology being one of them, that have helped lower the cost for energy."
As quickly as wind technology has developed in the past 10 years, Fisas-Camanes said he expects that pace to at least continue and possibly accelerate. He said he expects many advances in the next 10 years, including a new generation of offshore and onshore wind turbines that will have more value for their owners and more developments in the components and controls of a turbine.
"It's an open book," he said. "If you look at how this industry has been evolving, it's amazing. It's a very dynamic, technology-driven industry with a focus on cost, and I think we'll see a lot of interesting things in the next 10 years."
This article was originally published on Power Engineering and was republished with permission.