Alternative analysis in soft-soft design for onshore wind turbine hybrid towers for future progressive heights

Abstract

ABSTRACT: The national renewable energy laboratory (NREL) through its researchers, advocated to reach tall winds with tall towers to enable continuous plant performance Improvements. This will cause an increase in clean energy production to satisfy the exponential demand. One of the difficulties faced by NREL and the wind energy industries at large, is providing the necessary supporting structure to reach tall winds and support the production machineries. Supporting structures have been developed in the past, but it faces constrains today from structural stability and cost as it advocates to increase into the high winds. Some of the constraints within structural stability and cost are the main core of this research work. A battery of hybrid concrete-steel towers with variable heights were being analyzed in two different ways to obtain soft-soft hybrid towers. Soft-soft hybrid towers are the most cost-effective towers with higher abilities to move up to tall winds. The natural frequency of an installed wind turbine tower determines its characteristics (soft-soft, soft-stiff, stiff-stiff) under maximum operations. The two-careful analysis was carried out under the following dimensional characteristics of the hybrid towers in a constant environmental condition; 1) Increasing the bottom concrete diameter with different concrete wall thickness and a constant steel height for different hub heights. 2) Vary the concrete and steel heights with a constant wall thickness for steel and concrete. Observing the results, it was shown that; soft-soft hybrid wind turbine towers have a greater ability of growing to higher height with a reduced concrete wall thickness and base concrete diameter. The cost of transportation is favorable due the reduced diameter and weight of steel panels.