Life cycle energy and environmental emissions of offshore wind power in China

China’s wind power has been through a rapid development, dominating both annual and accumulative installed capacity of the world since 2011. However, the majority of the installed capacities locate in northern areas, whereas... [ view full abstract ]

China’s wind power has been through a rapid development, dominating both annual and accumulative installed capacity of the world since 2011. However, the majority of the installed capacities locate in northern areas, whereas the country’s electricity demand pressure mainly exists in coastal regions in the east. Such gap between wind power generation and consumption makes offshore wind power development a rising interest among government, industry and academia in China.

Compared to onshore wind power, the offshore technology requires more resource inputs for the facility construction and operation due to more complex site environment. However, existing literatures about China’s wind power footprint calculation are relatively rare, and mostly focus on onshore wind farms. To better understand the energy and environmental performance of offshore wind power in China, this study employs the process-based life cycle inventory (LCI) model to calculate the life-cycle energy consumption, greenhouse gas (GHG), SO₂, NO_x, and PM_2.5 emissions associated with wind electric power technology deployment. Results are helpful to identify the opportunities for environmental improvement in offshore wind energy utilizations, and thus contribute to cleaner power transitions in China. 

This study selected the first offshore wind project in China—the Donghai Bridge Offshore Wind Farm—for case analysis, but model results are referable for the country’s broader offshore wind power practices attributed to the representative technologies and processes of the case wind farm. Results show that: (1) The life cycle energy of the offshore wind farm is estimated at 2.28E+09MJ, or 0.39MJ/kwh, with the emission intensity of 25.46g CO₂-eq/kWh for GHG, 0.02 g/kWh for PM_2.5, 0.06 g/kWh for SO₂ and 0.09 g/kWh for NO_x. (2) For different life cycle stages, the wind turbine preparation and foundation construction is the main contributor to the life-cycle energy use and GHG emissions, 77.40% and 78.44% respectively. The energy payback time of the case wind farm is 2.68 years and the energy payback ratio is 9.32, implying attractive energy benefits associated with involving high shares of wind energy in China’s grid. (3) Compared to the energy and emission intensity of onshore wind farm systems, results of the offshore wind farm are obviously higher. Although the offshore wind power plant receives more favorable wind sources and thus has more life-cycle electricity yields compared to conventional onshore wind farm, the incremental environmental costs of the off-shore technology are still uncoverable.