i think it would be difficult to get a job as a "renewable energy engineer". please correct me if i'm wrong. i think you'd be better off doing a civil or electrical engineering degree, then specialising further down the track after having worked for a few years - either through a masters degree, or just through steering yourself in that direction job-wise.
the photovoltaic engineering degree is structured well at UNSW though, because you choose a strand such as mathematics, physics or electrical engineering (since there aren't all that many pv-specific subjects) -
which means that if you can't get a job as a pv engineer (which i think would be almost impossible), then you could at least scrape a job as something else and have a bit of knowledge behind you
but i am sure there are people out there with a wide variety of experiences with these smaller environmental engineering degrees, so if you are truly passionate about renewable energy or pv then don't let me talk you out of it