Design Optimization of Lattice Wind Turbine Towers Subjected to Earthquake Forces

Abstract

Onshore wind offers a green and renewable energy source, and onshore wind energy harvesting is one of the fastest growing industries in the world. The cumulative wind power capacity of the United States has grown from 3,000 MW in 2000 to over 20,000 MW in 2010. The major portion of the construction cost of wind farms is due to turbines, while the cost of the towers constitutes approximately 20% of the total cost. However, in such a growing market, there is still room and interest to reduce the cost of projects through achieving economy in tower design. The selection of proper turbine height and size depending on the location of the wind farm is the key factor in optimizing the installation cost. This paper evaluates and compares the cost of energy (COE) for a total of 10 tower height-turbine size combinations. Lattice (rather than monopole) towers are investigated for providing a cost-effective solution for small and medium size turbines as the ones considered here. With the number of wind farms increasing, it is inevitable that a significant number of wind turbines will be established in seismically active areas where the design forces are severe. Therefore, an earthquake-prone region is selected for the case study and seismic forces are included in the analysis. The results provide direct insight on the selection of the optimal tower alternative for a given location considering the height and turbine size despite the fact that the effects of the total number of towers in the farm and their location with respect to each other are not evaluated here.