Foundation and Installation System to Reduce the Cost of Distributed Wind Turbines

The United States Department of Energyĺs Wind Vision Report states that wind power will provide 20% of the nation's electricity supply by 2030 and 35% by 2050. The pursuit of these targets will require full utilization of the nationwide economic potential for distributed wind power; the National Renewable Energy Laboratory has cited this potential as 48 gigawatts by 2030 and 85 gigawatts by 2050. It is also estimated that, prior to capture, the capital cost associated with distributed wind turbine installations must be reduced 52% by 2030 and 71% by 2050. In the past, small wind turbines have struggled to reach cost-competitiveness in the greater renewable energy marketplace due to, in large part, high support structure costs and a highly variable installation process impacting both cost and quality. The technology proposed herein will provide immediate, industry-wide cost reductions that will accelerate the deployment of distributed wind and support the realization of these targets. This SBIR effort aims to validate a novel foundation and installation system ľ a system that will reduce the average construction time of a distributed wind project from 34 days to 5 days and reduce foundation/installation costs by 46%. Unlike typical wind turbine foundations that use concrete to transfer wind turbine loads into the surrounding soil, the proposed foundation uses a steel casing. By eliminating the use of concrete as a structural component, the foundation avoids the 28-day cure time inherent to structural concrete. As a result, distributed wind turbine projects can be constructed in days, not weeks. During Phase II, two foundation variants were developed to accommodate installation in diverse geotechnical conditions: 1) a Drilled Shaft with Embedded Casing (DSEC) foundation for stiff soils, and 2) a Vibratory Caisson (VC) foundation for soft soils. The DSEC foundation was successfully installed and tested (Figure 1). It was ready for turbine install in just 4 days, 7x faster than a typical concrete spread pad foundation. The Vibratory Caisson (VC) foundation, however, could not be tested at the Phase II test site due to the lack of soft soils for which it was designed. The goal for the Phase IIB project is to install and field test the VC foundation. The foundation and installation system will thrust the distributed wind industry into a new era of cost-competitiveness and growth. The proliferation of distributed wind power will unlock gigawatts of untapped clean energy potential, accelerate the dominance of domestic manufacturing, and create tens of thousands of skilled job opportunities nationwide