Wind turbine redux: Vertical-axis technology and offshore breezes

Tuesday, 31 July 2012 11:08

News & Events - Engineering News

The adoption of wind turbine technology in the U.S. has been slower than initially expected, as progress has been delayed by renewable energy opponents and growing sentiment that these energy sources are less efficient than other sources.

However, a redesigned type of wind turbine is helping to solve some of the problems presented by the standard model, according to Science Daily.

Researchers at Sandia National Laboratories are re-evaluating vertical axis wind turbines (VAWTs) and are hoping that key tweaks to the design of these energy sources will help to solve some of the problems associated with harnessing energy from offshore breezes.

According to the news outlet, VAWTs have been around since the early days of wind energy research, but the potential for these alternative designs have just been realized by Sandia researchers.

Cost advantages

Due to the difference in the economic models of land-based turbines and offshore windpower - challenges presented by installation and operational issues - VAWTs could help to eliminate some of the problems associated with generic wind turbines.

Three cost-related advantages attributed to the VAWT model were identified by Sandia researchers, according to Science Daily.

The VAWTs would allow for a reduction in operating costs due to a lower center of gravity, less complexity in the design of the machine and an increased ability to scale the turbine to larger sizes.

The engineering research done by Sandia scientists found that a lower center of gravity helps to improve the stability of the VAWTs in the water, along with lessening the gravitational fatigue loads.

According to the news outlet, the ease of maintenance for VAWTs has also influenced the thinking of Sandia researchers, as everything is located at or near the surface. Fixing the massive structures is easier and less time-consuming, leading to a further cost reduction.

Potential for simple design

Sandia researchers have lauded the simplistic design of VAWTS, and the process of developing advanced rotor technologies has progressed rapidly, thanks in part to support from the U.S. Department of Energy.

"VAWTs are elegant in terms of their mechanical simplicity," said Josh Paquette, one of Sandia's two principal investigators on the project. "They have fewer parts because they don't need a control system to point them toward the blowing wind to generate power."

The circular design of the physical turbines is supported by larger rotors, according to Discovery News, which could lead to increased output.

Despite the promise of VAWTs, several key design issues have presented themselves during the planning process.

Engineering research efforts have focused on designing a VAWT blade that is very large, gracefully curved and extremely light - a challenge that could delay the adoption of the alternative turbines.

According to the news outlet, Sandia researchers are hopeful that progress will be swift in this process, as the last and most widely used VAWTs were built during the 1980s. Science has moved forward by leaps and bounds in the sector since then, and advances in blade design and materials could expedite the discovery of a successful model.

Reinvigorating VAWT research could be initially difficult, but once the design process begins, progress lead to the production of a game-changing turbine that will propel the sector forward.

"Underpinning this research effort will be a tool development effort that will synthesize and enhance existing aerodynamic and structural dynamic codes to create a publicly available aeroelastic design tool for VAWTs," Matt Barone, the other principal investigator for the project, told Science Daily.