Based on a real case study, this article addresses the issues that can be encountered during project planning when a wind resource assessment programme (WRAP) is not adequately designed. The study highlights the uncertainty induced by vertical and horizontal extrapolation of the wind resource. The impact of these parameters on energy production is demonstrated based on simulations using commercial wind resource models. The resulting conclusions highlight the importance of well-designed WRAPs. The experience, results, benefits and challenges of sodar (sound detection and ranging) use are briefly reviewed in the context of the complex terrain and operating conditions of Canada. Limitations encountered by numerical models (steady state wind flow model, CFD model) are also examined in a comparative case study.