Using Stirling Engines to Generate Electricity from the Sun

Wired News: Huge Solar Plants Bloom in Desert
Kage told me about these Stirling Engines recently, now I see in the news that they are going to use them to create a 500 megawat powerplant in the California desert. How much Oil will it take to produce these dishes and engines? If we run out of oil will we be able to fabricate things like this? HURRY!