Energy yield of small wind turbines in low wind speed areas

The objective of this paper is to compare several commercially available small wind turbines systems, namely a vertical axis type with three helical blades without power limiting control above rated wind speed, multi-bladed furling controlled horizontal axis type, stall controlled horizontal axis type and blade pitch controlled horizontal axis type. The comparison is based on the annual energy yield per swept area (kWh/m²) and cost per generated electricity (€/kWh) in a low wind speed climate. Results show that most systems did not meet the performance stated by the manufacturers. Calculated annual energy yield of some turbines were higher than measured values from field test by up to a factor of two. Results also show that in large diameter turbines the €/kWh is lower than in small diameter turbines while many small diameter turbines had higher kWh/m² than large diameter turbines. However, above 3m diameter, large diameter turbines performed better, having both low €/kWh and high kWh/m².