Power Take-Off Design Study for a Small-Scale Oscillating Surge Wave Energy Converter for Powering the Blue Economy Applications: Preprint

Jackson Wills, Nathan Tom, Senu Sirnivas

Research output: Contribution to conferencePaper


The power take-off (PTO) is an integral part of wave energy conversion, and the design process is nontrivial. Better PTOs, and better processes for selecting and designing PTO architectures for various applications, would benefit devices that assist in powering the blue economy by decreasing time and money spent on PTO design and increasing the overall energy capture performance of these devices. This paper chronicles the selection process of a PTO for a small-scale surge-type wave energy converter (WEC) for the purpose of informing future PTO selection processes. Three PTO architectures are evaluated in WEC-Sim: a hydraulic check valve PTO, a hydraulic active valving PTO, and a directly electrified PTO. Simple models of each PTO are constructed. Because a model for the small-scale device was initially unavailable, the PTOs are simulated on a large-scale device. The results are scaled down using Froude scaling and compared to results from directly simulating a small-scale model. Strong assumptions are made because this work is early in the design stages, and a coarse look at PTO options was desired. Specifically, the effectiveness of controls is investigated, along with the efficiency of energy conversion. However, energy capture is only part of the consideration; there are also logistic concerns to be considered when selecting a PTO. For example, components for large-scale WECs are so large and expensive that it may make sense to custom-build PTO components, but small- scale WECs would benefit from off-the-shelf availability because the cost of customization would be a significant portion of the total capital cost of deployment at a small scale. Submersible, off-the-shelf components are much easier to source for hydraulic PTOs. Because of highly effective controls, efficient energy conversion, and availability of marine-grade components, an active valving hydraulic PTO is selected for this small-scale surge-type WEC.
Original languageAmerican English
Number of pages13
StatePublished - 2023
Event2023 International Mechanical Engineering Congress & Exposition - New Orleans, Louisiana
Duration: 29 Oct 20232 Nov 2023


Conference2023 International Mechanical Engineering Congress & Exposition
CityNew Orleans, Louisiana

Bibliographical note

See NREL/CP-5700-89205 for paper as published in proceedings

NREL Publication Number

  • NREL/CP-5700-86187


  • electric PTO
  • energy conversion/systems
  • hydraulic PTO
  • modeling and simulation
  • power take-off
  • renewable energy
  • wave energy converter


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