Offshore use of vertical-axis wind turbines gets closer look

Sandia National Laboratories' wind energy researchers are re-evaluating vertical axis wind turbines (VAWTs) to help solve some of the problems of generating energy from offshore breezes.

Basing their work on decades of wind energy research and experience, Sandia engineers are creating several concept designs, running those designs through modern modelling software and narrowing those design options down to a single, most-workable design for a VAWT turbine-blade. Results aren't in, but the early favourite for further testing is the Darrieus design. (Illustration by Josh Paquette and Matt Barone).

Though VAWTs have been around since the earliest days of wind energy research at Sandia and elsewhere, VAWT architecture could transform offshore wind technology.

The economics of offshore windpower are different from land-based turbines, due to installation and operational challenges. VAWTs offer three big advantages that could reduce the cost of wind energy - a lower turbine centre of gravity; reduced machine complexity; and better scalability to very large sizes.

A lower centre of gravity means improved stability afloat and lower gravitational fatigue loads.

Additionally, the drivetrain on a VAWT is at or near the surface, potentially making maintenance easier and less time-consuming. Fewer parts, lower fatigue loads and simpler maintenance all lead to reduced maintenance costs.