Simple Modular Technology (SMarT) Tower Systems for Free-Standing Small Wind Turbines

The cost of electricity for small wind turbines is too high, and the installation process is too cumbersome, to achieve the widespread deployment goals of industry stakeholders. Guyed towers, which are traditionally the least expensive to erect, represent one approach to cost savings, but these systems have a larger footprint, require more maintenance, and are less visually appealing than the monopole towers preferred by many customers. Therefore, this project will develop technology to address the construction of the logistically cumbersome and cost inefficient monopole tower systems (foundations plus towers). For the foundation, dramatic simplification is achieved by inexpensively shipping all required foundation materials (except concrete) directly to the installer. The tower, which will be composed of a hybrid metal-fiberglass, will weigh about half as much as steel towers, will be inexpensive to ship, and will be much less costly than traditional monopole alternatives. In Phase I, 402 foundations were installed in 36 states and 9 off-shore locations. Both the towers and foundations were evaluated and approved by tower engineering professionals. Phase II will involve conducting field tests, developing improved components, optimizing the designs, and testing the system at the National Renewable Energy Laboratory. Commercial Applications and other Benefits as described by the awardee: The proposed tower system should be suitable for use on all small wind turbines employing free-standing towers. With this system, a typical turbine on an 18.3 m (60 ft) tower would have an installed cost saving of approximately 30%. The technology would thus be a tool for promoting the expansion of wind turbines in the U.S