This essay from Energy Bulletin makes the point that "an enormous amount of fossil energy is required to manufacture, install and operate all forms of renewable energy systems. Without the input of fossil fuel the existing renewable energy projects could never have been built and could not be maintained in operation." The author, Roger Adair, who worked for ten years on wind systems in and around the British Isles, notes that renewables "are manufactured in largely fossil-fuelled factories employing tools, equipment and components produced in other fossil fuelled factories. The raw materials and components used require energy intensive extraction and fabrication techniques to produce, and along with the finished products, also have to be transported substantial distances, often by road." At any wind farm "you will find an abundant selection of fossil-fuelled giant earthmovers, cranes, cars and trucks in use. In addition enormous low loaders will be coming and going delivering massive mechanical parts, towers, nacelles, generators, gearboxes, transformers, power cables and blades from hundreds or thousands of miles away."
Adair concludes that the prospects for renewable power in a post peak oil world are very small indeed, a point also made by Jim Kunstler in his The Long Emergency. Says Adair: "Large and complex systems, particularly in remote and environmentally challenging environments such as wind farms, especially off shore, will probably be early renewable energy casualties of the decline in oil supply."