In the ring generators of large wind turbines, coils of up to several hundred kilometers of flat and round copper wire provide environmentally-friendly electricity generation. In the large offshore wind energy power stations in the North- and Baltic Seas, up to 30 t of copper is used in each wind turbine.

A 5 MW installation in the North Sea operates for about 3 000 hours per year (onshore installations = about 1 500 – 2 000 hours per year), and produces about 15 000 MWh of electricity. Assuming 600 g CO2/kWh, this avoids 9 000 t CO2 per year. The 9 000 t of CO2 avoided thereby means, when translated into the 30 t copper used, that each tonne of copper contributes to a saving of 300 t CO2 per year.

About 1.5 MWh of electricity is required to produce one tonne of copper, and thus less than 2 t CO2. Within the space of a year, one tonne of copper has saved more than 150 times the CO2 that was generated when it was produced in Germany. Over a 10-year period, the amount of CO2 avoided rises to a total of 3 000 t CO2 per tonne of copper.