Recently, RCAM Technologies was awarded a $1.25 million grant from the California Energy Commission to develop and test 3D printing technology that would allow wind turbines to be constructed directly on site, eliminating the need for trucks to haul the giant tower sections from one location to another. Cottrell formerly worked for the National Renewable Energy Laboratory (NREL), which he left in May to pursue the grant. Using NREL’s levelized cost of energy (LCOE) modeling tools, RCAM estimates that a 140-meter wind turbine would increase electricity production by more than 20 percent at a site with moderate wind shear, lowering electricity costs.
Under the terms of the agreement with the California Energy Commission, RCAM Technologies will design the lower half of two wind turbine towers measuring between 140 and 170 meters tall. While the upper halves of the towers will be constructed using conventional tapered steel assembled in sections, the lower halves will be constructed onsite from reinforced 3D printed concrete. Prototype sections of the towers will be 3D printed using a robotic arm and 3D printer, and will be tested at the University of California, Irvine.
According to NREL, the best wind power sites, which are located in the Great Plains, are posting annual capacity factors of more than 50 percent. The rest of the country, however, isn’t meeting the levels needed to compete with other energy technology such as natural gas and even solar photovoltaics. Taller wind turbines could make a big difference in the wind power levels of the whole country.
Aaron Barr, a Senior Consultant with MAKE Consulting, comments that concrete wind turbines have been used for a decade in Europe, but that they have used precast concrete fabricated in sections and shipped to the turbine site.
However, the grant request submitted to the California Energy Commission estimates that 3D printing the towers “will enable fabrication of a wind turbine tower onsite, in one day at half of the cost of conventional steel towers, and reduce the levelized cost of wind generated electricity in a low wind speed site by 11 percent.”
“Performing on-site pouring of concrete towers can present some cost savings in logistics and material cost and present one of the most promising applications of 3-D printing in the wind energy industry,” he says. “The specialized equipment and concrete curing times would significantly increase the construction cycle of a typical wind plant. Most U.S. wind plants are able to install turbines at a pace of one turbine per day or faster, given that all turbine equipment has been delivered to on-site staging areas. Use of an in-situ concrete tower solution dramatically increases this installation cycle, adding cost and execution risk to the wind plant development.”
Considering that houses have been 3D printed in 24 hours, it isn’t hard to believe that 3D printing could match the current time needed to fabricate wind turbine towers, if not reduce it. RCAM Technologies has been in contact with other wind turbine manufacturers and is discussing potential partnerships; in the meantime, it is working with UC Irvine throughout the prototyping stage. If the project is successful, it could mean greatly increased rates of wind power and greatly reduced energy costs – first for California, then ultimately for the whole country.
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