This paper focuses on the effect on people's utility of the potential environmental impacts of wind farm developments. We report on research designed to provide insight into their preferences. and we show, how two alternative choice modelling techniques can be used to estimate them. Our results show that significant social costs in the form of environmental impacts can be associated with wind farm developments. As relative environmental values are revealed by these methods, it Would be possible to develop wind farms in such a way that minimises the total social costs of the investment and which maximises its net benefits.