Hydro Energy Hydroelectric, Waves and Tides

Mechanical Energy Due to gravity Hydropower from dams Tides Due to Waves Surface Currents Underwater Currents

Hydroelectric Power Unlike steam powerplants, work instead of heat is directly available. Animation

Equations

Power Production Itaipu Hydroelectric power station with a capacity of 12,600 MWe is the largest power plant in the world.

Tidal Power

Newton’s Law of Gravitation

Tides Gravity and centrifugal forces are in opposite directions

Spring and Neap Tides

Tidal Power Station

Tidal Power Stations The only operating tidal power plant is in the Bay of Rance Estuary Built in 1967 Power Production = 160 MW R=11.4 m; A=22 sq.km Six other experimental tidal plants each generating less than 1 MW

Impact Advantages Clean Renewable No waste Protecting coastlines against storm surge Water Recreation Disadvantages Intermittent Disruption in local ecosystem (seabirds and fish habitats

Energy From Waves

Wave Power Waves are characterized by their wavelengths (length from crest to crest), amplitude (height from crest to trough), and period (time between two successive waves). Average wavelength of waves is about 120 m. The maximum power a wave carries is about 100 kW/m in high seas, 60 kW/m around the Atlantic coasts of Europe and less than 20 kW/m off the southeast of the United States.

Surface and Deep Ocean Waves Surface waves are neither longitudinal nor transverse. surface waves undergo circular motions. The motion of particles tends to decrease as one proceeds further from the surface.

The Oscillating Water Column OSC works by forcing air moving up and down in a closed column causing a turbine to turn. As a wave enters the column, it increases the pressure within the column and forces air up the column past a turbine. As the wave retreats, the air is drawn back past the turbine due to the reduced air pressure on the ocean side of turbine

Tapered Channel

Archimedes Wave Swing

Wave Ducks

Siting Near-shore vs. Off-shore Efficiency Cost Noise Visual