Business Weekly - Cambridge, UK

The St John’s Innovation Centre-based company has developed a generator for use in wind-powered electricity farms which makes maintaining the units, predicted at £30k per tower, a breeze.

Wind Technologies Ltd, the result of a collaboration between Dr Richard McMahon at Cambridge University and Prof Peter Tavner at Durham University, has developed a new maintenance-free generator which doubles the lifetime of wind installations.

The UK currently has 1899 wind turbines in operation, generating a combined maximum output of 2297MW of electricity, with a further 513 currently under construction.

As the world wakes up to the immediate need to find ecologically sound forms of energy generation, wind power has taken off around the world, with European capacity increasing by 20 per cent in the last year alone.

If Wind Technologies’ new Brushless Doubly-Fed induction Generator (BDFG) were installed in every unit currently generating in the UK alone, the operating companies would stand to save a combined £72m over the 20 year lifetime of the units.

In Germany, however, a world-leader in wind power technology, the country is already generating over 20 times the amount of electricity produced in the UK, making the associated maintenance costs 20 times higher.

“It depends on the size of the generator,” said the managing director of Wind Technologies, Dr Ehsan Abdi.

“But for a 3MW system, we expect the cost to replace the brush gear to be around £1500 per change, which is done once or twice a year. So when you multiply that by the 20-year lifespan, it comes out at around £30k savings per unit. With the brushless system, this cost is completely removed.”

In more than 90 per cent of new wind turbines in the world, the wind’s power is converted into electricity via a doubly-fed slip ring induction generator (DFIG), which uses huge, costly slip-rings as part of the drive system.

Studies have shown that one of the main issues with wind power generation are the associated ‘brush-gears’ with the slip rings, which require maintenance on an annual basis.

Wind Technologies has developed a ‘brushless’ system, which employs two stator windings in a single frame in combination with a special form of ‘brushless’ rotor, which along with eliminating the need for brush replacement, also doubles the life time of the generator from 90,000 hours to 180,000 hours before failure, according to Abdi.

The company has approached “all of the big wind turbine developers and manufacturers,” including Europe’s biggest engineering conglomerate, Siemens.

Abdi said that they have received considerable interest from a wide range of companies, all of which want to see a working prototype on the scale that the technology will be used in the field.

“We’ve got a laboratory prototype, but haven’t yet tested it in an industrial-sized turbine.

“We have plans to test it on a 600kW generator in Germany in July or August next year, which will give us some figures a chance to demonstrate the working technology to the turbine companies.

“In a year from now, we expect the project to be basically achieved.”

The application of the technology is not limited to large-scale industrial applications, however, and the company plans to demonstrate its use in a mid-sized, 20kW turbine, which could be installed for home use, on Cambridge University’s West Cambridge site.

“We are just awaiting planning approval from Cambridge City Council, which we expect to hear about by the end of November.”

The company received £25k of funding from EEDA for the project, with the £25k balance to be supplied by internal investment, Abdi said.

EEDA has supplied further funding towards the company’s patent applications, which Wind Technologies has had pre-approval for.

Abdi said: “After working on the project for over eight years now, we are quite sure that we can protect the intellectual property and are expecting to file three patents.“

The company is looking to licence its technology to one of the big turbine developers, with the company aiming towards a “five to 10 per cent share of the royalties.”

“In five years we could be licensing the technology, because we are not looking at going into manufacturing – or we could be consumed by one of the big firms.”

Along with backing from EEDA, Wind Technologies also received support from the University of Cambridge Challenge Fund, and Cambridge and Durham Universities.

The company currently consists of six board members in executive or advisory roles, and three PhD students.