Climate Effect Assessment of Ideal Large-Scale Solar and Wind Power Farms in Northwest China

Solar energy and wind energy show the greatest potential as sources of renewable energy when it comes to large-scale development and utilization for satisfying energy demands, reducing CO₂ emissions, and solving the climate change problem. However, the energy density of solar and wind energy is relatively low. The conversion of energy structures from being fossil fuel dependent to utilizing clean energy from solar and wind energy requires the construction of solar and wind farms over a very large region. Consequently, this may lead to changes in the local and regional climates through the land–air interaction process and even produce remote climate impact through the teleconnection process. Using the RegCM 4.5 regional climate model, this study simulates the climatic effects of building solar and wind farms in arid and semi–arid regions of Northwest China. Results show that: (1) large-scale establishment of solar and wind power plants across Northwest China will lead to an increase in the net shortwave radiation, sensible heat flux, and near-surface temperatures. Precipitation increases in the western Xinjiang Province, Hexi Corridor, and Huang–Huai valley. (2) The influence of surface albedo on climate is greater than that of surface roughness, suggesting that the climatic effect caused by solar energy utilization is greater than that caused by wind energy. (3) Albedo changes cause cyclonic circulation at the lower levels, leading to a southerly anomaly in central China and an easterly anomaly in Northwest China. At the upper levels, an anticyclonic circulation is caused, which can affect most of China. (4) When solar and wind power plants are built on 20% of the area of Northwest China, no significant change can be caused in the local near-surface temperature. Though the precipitation increases slightly in the Hexi Corridor region, the regional and remote circulation changes are very weak and the climate effect is negligible.