overview of wave energy conversion technologies alex ruane 10/27/05
TRANSCRIPT
Overview of Wave Energy Conversion Technologies
Alex Ruane10/27/05
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
• 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: Falcao, 2004
Source: Clement et al., 2002