Vertical axis wind turbines could replace conventional offshore ones

Vertical axis turbines could replace conventional offshore ones, study finds
Emily Smoucha
28th February 2011
Vertical axis wind turbines could provide an alternative method of green energy production from conventional horizontal offshore wind turbines, a study has found.
The Energy Technology Institute (ETI) commissioned the NOVA project to study whether using vertical axis turbines could help reduce the cost of energy production offshore.

Estimates show that if offshore wind reaches a 30 gigawatts (GW) capacity, then about 50 million tonnes of CO2 could be saved each year. But turbulence can greatly affect the productivity of conventional, horizontal offshore wind turbines, making them run less efficiently.

The £2.8 million NOVA study examined whether vertical axis wind turbines could offer cheaper electricity due to the size and scale of the machines as well as simpler maintenance when compared to conventional turbines.

"Traditional horizontal offshore wind turbines have adapted the existing technology found in onshore turbines," said Dr David Clarke, ETI chief executive. "The NOVA feasibility project is a radical concept which demonstrates that vertical axis machines are technically feasible and could be used in certain circumstances."

Aerogenerator X
The NOVA project began in 2009 and tested Wind Power Limited's 10MW Aerogenerator X vertical axis turbine. It was conducted alongside two other ETI offshore wind studies, Deepwater, which has concluded, and Helm Wind, which will be completed shortly and is assessing the complete design system for an offshore wind turbine array, including installation, design, aerodynamics, electrical systems, control and maintenance.

"[NOVA] provided us with lots of information that, along with the results from our other two novel turbine projects, will help inform our decisions on the type of technologies we will be looking for in the next stage of our offshore wind programme," Clarke said. "The next stage should see a demonstrator built and tested at sea, which will build on the insights from all three projects."

Floating turbines
Additionally, the study investigated how both fixed and floating structures performed. It concluded that the floating turbines functioned well at areas over 60 metres, as high wind speeds help reduce the cost of energy production.

"It has been really exciting to see how the design and cost of energy for such an innovative concept has potential to bring about a step change in the offshore wind industry," said Annie Hairsine, of OTM Consulting. "Significant experience and knowledge has been developed in Phase One placing the UK in a unique position to lead the market for vertical axis turbines."

The NOVA project was conducted by a consortia that included Wind Power Limited, OTM Consulting, Cranfield University, , the University of Strathclyde, Sheffield University, James Ingram & Associates, CEFAS and QinetiQ.