Reducing the Carbon Footprint of Wind Energy : What Can Be Learned from Life-Cycle Studies?

To compare the effects of wind energy generation with other energy options, carbon dioxide equivalent emissions must be estimated over the complete life cycle. A variety of life cycle assessment and carbon footprint studies have been conducted regarding greenhouse gas (GHG) emissions and other environmental impacts of wind turbines. Methods of reducing emissions from the installation phase would include the use of heavy-duty equipment which is more fuel-efficient or operates on alternative fuels. Compared to recycled materials, acquisition and processing of virgin materials requires greater energy and, thus, produces more GHG emissions when the energy is supplied by fossil fuels. Generally, turbines in the MW size range emit less GHG emissions per kWh of electricity generated than turbines in the kW size range. The low value was for a 3 MW turbine; GHG emissions were found to decrease with increasing turbine size, reflecting economies of scale.