Though it's a lot of area, the land can still be used for sheep and cattle grazing as before - and the farmers receive payment for the use of their land (about $5,000 per MW). By my maths, that would mean farmers of this region would be receiving about $2.1 million each year, from the 420 MW wind farm.
For me this sounds like such a great story. Producing sizeable amounts of renewable energy and providing a second source of income for the farming community. In fact, sometimes, during tough farming years, windpower can save the farm.
PS. While this is the biggest wind farm in Australia (hopefully a record that is soon beaten) the world's biggest is much larger - 1064 MW in India.