Estimating maximum global land surface wind power extractability and associated climatic consequences

The availability of wind power for renewable energy extraction is ultimately limited by how much kinetic energy is generated by natural processes within the Earth system and by fundamental limits of how much of the wind power can be extracted. Here we use these considerations to provide a maximum estimate of wind power availability over land. We use three different methods. First, we use simple, established estimates of the energetics of the atmospheric circulation, which yield about 38 TW of wind power available for extraction. Second, we set up a simple momentum balance model to estimate maximum extractability which we then apply to reanalysis climate data, yielding an estimate of 17 TW. Finally, we perform climate model simulations in which we extract different amounts of momentum from the atmospheric boundary layer to obtain a maximum estimate of how much power can be extracted, yielding 36 TW. These three methods consistently yield maximum estimates in the range of 17–38 TW and are notably less than recent estimates that claim abundant wind power availability. Furthermore, we show with the climate model simulations that the climatic effects at maximum wind power extraction are similar in magnitude to those associated with a doubling of atmospheric CO2. We conclude that in order to understand fundamental limits to renewable energy resources, as well as the impacts of their utilization, it is imperative to use a thermodynamic, Earth system perspective, rather than engineering specifications of the latest technology.