Overview of Wave Energy Conversion Technologies Alex Ruane 10/27/05

Tech Overview Wave Energy Basics Tapered Channel (TAPCHAN) Devices Floats or Pitching Devices Oscillating Water Column (OWC) Devices AP Photo, NYC, 10/26/05

Wave Energy Basics Wave energy is derived from surface winds across entire ocean Mostly potential energy Waves lose energy as they are refracted by shallow ground and break Best sites for wave energy extraction need consistent waves often near cliffs with deep bottom

Tapered Channel (TAPCHAN) Devices Waves are focused through an opening into elevated reservoir Potential energy gathered using proven hydro-electric technology Requires huge (8500 m2) collecting pool and wide entrance from “Feasibility of Developing Wave Power as a Renewable Energy Resource for Hawaii”, Hawaii Department of Business, Economic Development, and Tourism

Floating or Pitching Devices Normally anchored to shoreline or seafloor Wave motion drives fluid through a pump or propels a turbine Energy may be extracted from both pitch and heave motions Normally Offshore Devices sit in higher energy environment requires connecting cables Source: “Feasibility of Developing Wave Power as a Renewable Energy Resource for Hawaii”, Hawaii Department of Business, Economic Development, and Tourism

Oscillating Water Column (OWC) Devices Source: Falcao, 2004 Blow Hole as inspiration? Trapped air is expanded and compressed by changing wave level Propelled through air turbine both directions of airflow generate energy Release valve helps prevent stalling maximum efficiency 0.7 - 0.8 Source: Clement et al., 2002