Using the world's largest data set of in situ ocean current measurements, combined with a high-resolution topography roughness data set, we use a model-assisted hierarchical clustering methodology to estimate the global lee wave generation rate at the ocean floor. Our analysis suggests that internal wave generation contributes 0.75±0.19 TW (±2 standard deviation) to the oceanic energy budget but with a strong dependence on the Brunt-Väisäla (buoyancy) frequency climatology used. This estimate is higher than previous calculations and suggests that internal wave generation may be a much more significant contributor to the global oceanic mechanical energy budget than had previously been assumed. Our results imply that lee wave generation and propagation may be a dominant sink of at least half and potentially the overwhelming majority of ocean surface wind work on the geostrophic circulation.