A review of surface engineering issues critical to wind turbine performance

Wind turbine performance can be significantly reduced when the surface integrity of the turbine blades is compromised. Many frontier high-energy regions that are sought for wind farm development including Nordic, warm-humid, and desert-like environments often provide conditions detrimental to the surface of the turbine blade. In Nordic climates ice can form on the blades and the turbine structure itself through a variety of mechanisms. Initial ice adhesion may slightly modify the original aerodynamic profile of the blade; continued ice accretion can drastically affect the structural loading of the entire rotor leading to potentially dangerous situations. In warmer climates, a humid wind is desirable for its increased density; however, it can come at a price when the region supports large populations of insects. Insect collisions with the blades can foul blade surfaces leading to a marked increase in skin drag, reducing power production by as much as 50%. Finally, in more and regions where there is no threat from ice or insects, high winds can carry soil particles eroded from the ground (abrasive particles). Particulate-laden winds effectively sandblast the blade surfaces, and disrupt the original skin profile of the blade, again reducing its aerodynamic efficiency. While these problems are challenging, some mitigative measures presently exist and are discussed in the paper. Though, many of the current solutions to ice or insect fouling actually siphon power from the turbine itself to operate, or require that the turbine be stopped, in either case, profitability is diminished. Our survey of this topic in the course of our research suggests that a desirable solution may be a single surface engineered coating that reduces the incidence of ice adhesion, insect fouling, and projects the blade surface from erosive deterioration. Research directions that may lead to such a development are discussed herein. (c) 2007 Elsevier Ltd. All rights reserved.