Effect of Site Wind Properties on Wind-Electric Conversion Costs

Abstract

The unit cost of energy production of windgenerators is examined by means of a model of the turbine power curve and the Weibull model of wind probability function, by applying the usual economic equations. The analysis is carried out in terms of dimensionless variables whose range of variability is defined by examining the data of 80 modern commercial wind turbines; likewise, the economic parameters are based on the present state of costs. The unit cost decreases asymptotically when α (ratio between mean wind speed and cut-in speed) – increases and shows a lower limit of 2 to 5 €cent/kWh. This cost depends both on the value of the machine parameter φ (ratio between nominal and cut-in speed) and on the basic prices. The effect of the Weibull shape parameter k is different according to the values of α and φ: with low α and high φ the unit cost increases along with k (that is with the regularity of the winds); the more α increases the less k affects the unit cost.

The sensitivity analysis shows that the windgenerator cost is the strongest term, and that α and φ are also significant. The saving from choosing the optimised wind turbine can be 1 to 6 €cent/kWh. The analysis of increasing the hub height shows financial benefit is not assured, as it can be positive or negative depending on the values of α, φ and the ground roughness.