The table below shows data for the main materials used in a wind turbine: the approximate mass used per \(\mathrm{kW}\) installed and the embodied energy per kg of these materials.

a. Use these data to estimate the total embodied energy of the materials in a 1 MW wind turbine.

b. The capacity factor for a typical land-based wind turbine is \(20 \%\). (Capacity factor is the equivalent fraction of the time that the turbine is operating at its rated capacity; thus a 1 MW turbine produces, on average, the equivalent of \(0.2 \mathrm{MW}\) of electrical power). How long will it take a \(1 \mathrm{MW}\) turbine to return the embodied energy of the materials of which it is made?

Bill of Materials Mass Per Installed Unit of Power Capacity Embodied Energy of Materials (kg/kW) Aluminium 2 (MJ/kg) 200 CFRP 7.5 480 Concrete 500 1.8 Copper 1.5 65 GFRP 7.5 160 Steel 120 25 Neodymium 0.012 85 (magnets) Plastics 5 80