He used IRender for the renderings. Here is what he has to say.
So here it is. Renders were done in iRender NXT and are as yet basic. Texturing is a problem, bitmaps simply won't do in a model this size, you get patterning, it looks ugly. But at least iRender is able to handle this 81MB beast, which is more than can be said of Vray... exporting 2D images from SU itself is rather more of a problem too...
I did these renders in the trial version of iRender, which runs out in 6 days, so I'm now considering buying it. It does have good RPC plant options that I'd love to experiment with!
Here's another render. I love this feature of iRender, it actually does true orthogonal renders.