A technical analysis and comparison of tubular and lattice towers for wind turbines

Abstract

The advancement of wind energy technology brings about an increase in the size and height of the wind turbine towers. As the upscaling of the conventional steel tubular tower is problematic, alternatives are being investigated. In this paper, several configurations were reviewed and the lattice tower was identified as a possible solution. This study analyses and compares the structural performance of the two tower configurations, tubular steel and lattice, of equivalent height, stiffness and mounted rotor, in two sets of tower heights, 120 m and 150 m. The towers are mounted by the baseline 5 MW turbine developed by National Renewable Energy Laboratory (NREL). The results indicate that lattice towers are a suitable alternative to the tubular towers, providing significant material savings for a similar structural behaviour. Comparable bending moments were recorded in the base of the structures. The most demanding operating condition of the wind turbines was identified to be system braking cause by a sudden increase in wind velocity outside of the operating range. The 150 m lattice tower responds with excessive displacement during this abnormal operating condition; this is a potential issue that can cause generator failure if not accounted for in the rotor design.