The design of the foundation for a Northern Power® 100 wind turbine (NPS™ 100) at a specific site is the responsibility of the project developer. Because soil conditions can vary dramatically from installation to installation, the project developer must conduct a geotechnical investigation at each site to determine what conditions exist. Those conditions must be taken into account by a competent structural engineer, licensed to practice in the jurisdiction of the site, in his design. The loads that are imposed on the foundation are defined in Northern Power’s document A00298, Northern Power 100 Application Requirements.
Designing a foundation for a wind turbine is not significantly different from designing a foundation to support any other structure, though wind turbines do have some dynamic issues that must be considered. This document is intended as an overview of foundation designs for an NPS 100.
Though there are many different approaches to supporting a wind turbine in different conditions, most sites are suitable for one of the three “standard” foundation types: spread, deep mono-pile, or pile. The sizes and quantities discussed in this section are rough order-of-magnitude and intended only for early-stage estimating. It is certainly possible that a properly designed foundation may wind up being either larger or smaller than the range of dimensions included in this document. Nothing in this section is intended to preclude the need for site-specific soil investigation and rigorous design of a footing for the site.
For more information on these considerations and their various elements, please download the Engineering Bulletin:
This document outlines the types of foundation and describes the considerations affecting each.
–Alan Axworthy, Director, Application Engineering