Life cycle assessment of CO2 emissions from wind power plants: Methodology and case studies

Wind energy plays an increasingly important role in the world’s electricity market with rapid growth projected in the future. In order to evaluate the potential for wind energy to mitigate the effects of climate change by reducing CO2 intensity of the energy sector, this study developed a new direct and simple method for estimating CO2 emissions per kWh produced during the life cycle of four representative wind power plants (three in developed countries and one in China). The life cycle analysis focuses on the wind power plant as the basic functional object instead of a single wind turbine. Our results show that present-day wind power plants have a lifetime emission intensity of 5.0–8.2 g CO2/kWh electricity, a range significantly lower than estimates in previous studies. Our estimate suggests that wind is currently the most desirable renewable energy in terms of minimizing CO2 emissions per kWh of produced electricity. The production phase contributes the most to overall CO2 emissions, while recycling after decommission could reduce emissions by nearly half, representing an advantage of wind when compared with other energy generation technologies such as nuclear. Compared with offshore wind plants, onshore plants have lower CO2 emissions per kWh electricity and require less transmission infrastructure. Analysis of a case in China indicates that a large amount of CO2 emissions could be saved in the transport phase in large countries by using shorter alternative routes of transportation. As the world’s fastest growing market for wind power, China could potentially save 780 Mtons of CO2 emissions annually by 2030 with its revised wind development target. However, there is still ample room for even more rapid development of wind energy in China, accompanied by significant opportunities for reducing overall CO2 emissions.