In other cases, discrepancies may be due to different LCA databases being utilized, or arise as a result of different assumptions being made regarding material types such as steel alloys in the face of uncertainty of the exact types of materials used in each component. This creates uncertainty, which we illustrate here using a simple calculation exercise. In one study (Burger and Bauer, 2007), ferrous metal content in the 800 kW onshore wind turbine, excluding the foundation, consists of 7 per cent cast iron, 78 per cent low-alloy steel and 15 per cent high-alloy (chromium) steel, while in a second study (Martinez et al.,