Try Planet Hell by Nightwish. The introduction lasts 1:15 in the video, and 1:11 in the studio version. They have plenty of other potential songs, such as The Kinslayer, Wishmaster, and The Pharaoh Sails to Orion.
If you want to be less strictly operatic, the most powerful song I know bar none is Image of the Beast by Christian Gothic band Saviour Machine. It may not be appropriate though, since its lyrics are overtly Christian and are easily heard. ‘The Sixth Judgement’ is another one of theirs to look out for, although I doubt you will be able to find it online. Oculus Ex Inferni by Symphony X is also great, as is The Walls of Babylon. You may also want to try The Howling by Within Temptation. Resign to Surrender by Epica is another one to try, as well as their Kingdom of Heaven. In fact anything by Epica is killer.
While none of these are strictly opera, and all are less than ten years old, one of them is bound to suit your project. Good luck!