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July 2013 www.sname.org/sname/mt deployment of sub-scale systems in wave tanks and open-water environments. Generator design and optimization. Our key accomplishments in this area include: ? Performance: production of more than one tesla of magnetic ux density change, a level of performance sucient to achieve the power density and energy generation assumed in our cost model ? Scale up: Core size was successfully scaled up from approximately 2.5 cm to more than 10 cm. To date, the generator testing has validated the accuracy of our predic- tive models for achievable ux change and power production ? Reliability: Magnetostrictive generators have been successfully subjected to more than 1.5 million load cycles (approximately 2.4% of the number of cycles expected over a 20-year lifetime). Following an initial decrease of approx- imately 2.5%, which can be attributed to core and coil heating, power production remained constant. Design and optimization of the PTO and overall system. We have executed design, prototype testing, and modeling activities to optimize the PTO and overall system. Finite element design engineering was used to maximize load transfer from the tethers to the magnetostrictive gener- ator and to evaluate, along with prototype testing, a variety of sealing methodologies that have been proven in analogous systems. At the system level, our work has focused on the modeling and simulation of a util- ity-scale system in central Oregon coast wave conditions. Executed in Orcaex by naval engineering consultancy Marine Innovation and Technology, these simula- tions output a time series of tether tensions. When combined with the generator perfor- mance model, these outputs can predict power generation as a function of wave con- ditions and system design. e simulations enabled us to design a system that can sur- vive a 100-year wave. We worked with Powertech Labs, a sub- sidiary of Canadian utility BC Hydro, to develop conceptual designs for the power electronics and transmission components of the MWEH system using o-the-shelf hard- ware. We also have carried out exhaustive design failure modes and eects analysis with external experts to prioritize techni- cal risks associated with the MWEH. Deployment of sub-scale systems. In 2010, we conducted two rounds of wave tank testing at the University of California at Berkeleys tow tank. In addition to accom- plishing preliminary reduction to practice, we were able to demonstrate high corre- lation between the predicted and actual generator output. In 2012, Professor Jim omson and his team at the Applied Physics Laboratory at the University of Washington designed a moor- ing system that enabled us to conduct the rst testing of iMEC-enabled hardware in uncon- trolled conditions at Lake Washington. e The architecture of the MWEH is similar to that of tension leg platforms used in the oil and gas industry, consisting of a partially submerged buoy anchored to a catenary-moored heave plate by taut tethers.