The Proven 15 kW turbine; designed for reliability and

performance

EWEC Athens 2006, CW32. Small wind turbine systems.

Proven Energy Ltd., Johnnie Andringawww.provenenergy.com

Next 15 minutes

• Products & company• Turbine design & safety• 15 kW blade development

– Blade material– Moulds and process– Blade tests

• Further Development• Turbine performance• Status

Products

• First turbine Rannoch Moor, now, 17 years later still up & running

• 2.5 and 6 kW• Transition from off-

grid to on-grid• Household and

professional customers

Company

• Based in Scotland; high winds and many remote islands• Export to over 30 countries• 2005; 150 turbines, growing over 50% year on year

Turbine design

• Simplicity: reliability• Direct drive• PM generator, no

rotating coil• Brake disk• Downwind, passive yaw• Low rpm; tip speed < 65

m/s; low noise

Safety mechanism

• Passive pitch: elastic hinge with prestressed springs• Blades cone downwind

15 kW development

• Same concepts as smaller turbines

• Basic numbers:– 9.5 m diameter– 95 …160 rpm– rated 11 m/s– Blade: twintex; 15 kg each

• Development started 3 years ago

Blade development

• 2.5 kW; full PolyPropylene as blade material– Tough and non-sticky

• 6 kW; wood epoxy– Manufacturing of larger shapes– Vulnerable (impact)

• 15 kW started with glass-epoxy

• ended with twintex (Glass with PP matrix)– As above and ‘recyclable’; melt PP from glass– However; ‘NEW’ material and process

Moulds

• Elevated temperature; expensive moulds

Process• Filling of mould• Blade has a rib• Vacuum forming in

oven

Blade testing

• Hinged blade; low bending moments (IEC)

• Static tensile & bending test

• Same design, same mould– Improvements in

production– Over 3-fold increase in

critical strength– More consistent quality

Further development

• Hub, Generator, Controller, Automatic brake• Covers are designed; styling of turbine

Turbine Performance

• Theoretical / experimental analysis of springs• Optimise power curve and safety mechanism

Status• PERFORMANCE was

achieved early• Establishing RELIABILITY

took longer, – especially with new production

process – Now entering final 6 months

live cycle test– Full scale production starts

2007• IEC 61400/2 standard and

procedures helpful