like other people said there's very few jobs in renewable energy in australia
see for yourself if you seek.com.au search for 'renewable energy' right now theres 108 matches, however about 70% or so of these are either in sales or unsuitable for a recent re graduate
(for comparison the term 'structural' returns over 3000 matches)
there is however plenty of opportunity overseas, specifically germany, japan and china.
remember thou that australia will have an emissions trading scheme by 2012. the australian climate exchange has already opened a few days ago (around 8.50$/tonne co2)
once the ets has opened carbon trading will be huge.
already re grads have made a start up to analyse business's co2 emissions (energy audits), helping them become 'carbon neutral' (business's will pay big $ for the +ve PR/image this generates), and other stuff like that
there will only be more demand for this sort of stuff once the ets is made compulsory for big companies
anyway if you want to be sure of a job after graduating, civil eng. or something like that is probably your best bet