Floating turbine platform ready to tap the 2 TW offshore potential

Foundations are a big part of land-based turbines and more so for those headed offshore. A solution to the tricky foundation problems is to omit them – let the turbines float. So far, only one turbine floats. It’s on a 100-m spar in Norwegian waters. Principle Power (principlepowerinc.com) has another idea in its WindFloat, a design based on concept studies in the oil and gas industry. Its several advantages, says the company, include dynamic stability that provides pitching and yawing low enough to allows selecting from the current stock of turbines. The platform can be assembled onshore and wet-towed to sites not visible from shore. The developer says its primary markets are the transitional (30 to 60m) and deep (>60m) offshore water in the U.S. and Europe, sites previously inaccessible. These have a wind potential of at least 2 terawatt.

WindFloat is fitted with horizontal water-entrapment plates at each column’s base. These stablilize the platform with additional damping and entrained water effects, allowing use of existing wind turbines. The platform’s stability is assisted by a closed-loop active ballast that mitigates wind-induced thrust forces, restoring the system to best efficiency following changes in wind velocity and direction.

Fabricating the structure onshore allows completing qualification tests at quayside in a controlled environment. The company adds that says commissioning costs are significantly less  when compared with monopole-jacket offshore support structures.

The mooring system uses conventional components such as chain and polyester lines to minimize cost and complexity. This also minimizes use of pre-laid drag embedded anchors and site preparation.

WPE

New platform lets turbines float offshore

A new floating platform would allow wind turbines to float offshore without water-depth restrictions. The WindFloat platform was conceived by engineering firm Marine Innovation & Technology and owned by Principle Power. The device is a floating support structure for offshore wind turbines.  The structure would let turbines sit in locations with excellent wind resources that were previously off limits because water depth exceeded 50m.

The WindFloat foundation has many advantages. It’s economic because it reduces the need for offshore operations during final assembly and commissioning. Also, its static and dynamic stability offers low pitch and yaw performance, enabling use of existing commercial wind turbine technology. Its design and size allow for onshore assembly, while its shallow draft allows for depth-independent sitting and towing it to sites not visible from shore.

The design and size of the WindFloat enables overall structure assembly onshore. Horizontal water-entrapment, or heave, plates at the base of each column significantly improve the motion performance of the system, due to additional damping and entrained water effects. A closed-loop active ballast system mitigates wind-induced thrust forces, restoring the system to optimal efficiency following changes in wind velocity and direction. A catenary mooring system uses conventional components, such as chain and polyester lines to minimize the cost. Pre-laid drag-embedded anchors minimize site preparation and impact.

Marine Innovation & Technology engineers used digital prototyping to create the WindFloat. The software from Autodesk, Inc. helped design and render the device in just three weeks. Multiple project proposals are being submitted for full-scale demonstration and utility-scale developments in the UK, Europe, and U.S.

Marine Innovation & Technology www.marineitech.com

Autodesk usa.autodesk.com