Page 28 - Wind Energy Handbook

2 INTRODUCTION

and Sweden. There was considerable uncertainty as to which architecture might
prove most cost-effective and several innovative concepts were investigated at full
scale. In Canada, a 4 MW vertical-axis Darrieus wind turbine was constructed and
this concept was also investigated in the 34 m diameter Sandia Vertical Axis Test
Facility in the USA. In the UK, an alternative vertical-axis design using straight
blades to give an ‘H’ type rotor was proposed by Dr Peter Musgrove and a 500 kW
prototype constructed. In 1981 an innovative horizontal-axis 3 MW wind turbine
was built and tested in the USA. This used hydraulic transmission and, as an
alternative to a yaw drive, the entire structure was orientated into the wind. The
best choice for the number of blades remained unclear for some while and large
turbines were constructed with one, two or three blades.
Much important scientific and engineering information was gained from these
Government-funded research programmes and the prototypes generally worked as
designed. However, it has to be recognized that the problems of operating very
large wind turbines, unmanned and in difficult wind climates were often under-

Figure 1.1 1.5 MW, 64 m diameter Wind Turbine (Reproduced by permission of NEG
MICON, www.neg-micon.dk)