How much wind power can the atmosphere actually supply?
Short answer. Less than the wind speeds suggest, because what limits a large wind farm is not how hard the wind blows but how fast the atmosphere replenishes the kinetic energy the turbines remove. That sets a ceiling of order 1 W/m² on large-farm power density, arising from pressure gradients acting through the Coriolis force — so the limit varies with latitude and weather, and open-ocean sites can exceed land generation threefold.
Why the question matters
Estimates of wind potential are often built by multiplying an available area by a power density measured at small scale. That method assumes the resource is a property of the land rather than of the atmosphere above it, and at the scales decarbonization would require, it overstates what is achievable.
Because turbines remove energy that must be resupplied from above, a wind farm changes the resource it is exploiting. That makes large-scale wind a question about atmospheric dynamics rather than about turbine engineering.
It also makes wind development a coordination problem, since one installation's wake reduces what a neighbouring one can generate.
What our research finds
- The roughly 1 W/m² ceiling on large wind-farm power density arises from horizontal pressure gradients interacting with the Coriolis force in the Ekman layer, making the limit depend on latitude and local meteorology (Antonini and Caldeira, 2021).
- As a wind farm grows, mean generation per unit of land falls and its wake shadow lengthens, bounding both how large a farm can usefully be and how far apart farms must be spaced (Antonini and Caldeira, 2021).
- The atmosphere over the open ocean can transport kinetic energy downward faster than over land, so generation over some ocean areas can exceed land generation by a factor of three or more (Possner and Caldeira, 2017).
- The available potential energy that drives the winds is generated principally in the tropics, from latent heat in the intertropical convergence zone, and in the polar night, where longwave cooling goes unopposed (Ahbe and Caldeira, 2017).
- Surface turbines could extract at least 428 TW and turbines throughout the atmosphere at least 1,873 TW, against about 18 TW of global primary power demand, so wind is limited by economics rather than by a global geophysical ceiling (Marvel et al., 2013).
- At the scale of global energy demand, uniformly distributed wind turbines would shift zonal mean temperature by about 0.1 K and zonal mean precipitation by about 1 per cent (Marvel et al., 2013).