Ocean Renewable Energies Overview

Ocean Renewable Energies

• The ocean is the largest solar collector, providing a vast amount of kinetic and thermal energy.
• This energy source is clean, predictable, sustainable, and strategic.
• Changes in salinity, thermal gradients, tidal levels, and currents, or ocean waves can be used to generate electricity.
• Over 100 known ocean energy technologies exist, with global potential equal to present worldwide electricity production.

Types of Ocean Energy

• Tides: Potential energy from tides can be harnessed using barriers across estuaries.
• Tidal Currents: Kinetic energy from tidal currents is harnessed using modular devices, currently under development and undergoing sea trials.
• Waves: Kinetic and potential energy of waves can be harnessed using modular technologies. Wave arrival times can be predictable or more variable.
• Salinity Gradients: Energy from mixing fresh and salt water can be harnessed using pressure-retarded reverse osmosis.
• Thermal Gradients: Energy from temperature differences between surface and deep ocean water can be harnessed using Ocean Thermal Energy Conversion (OTEC) processes.

Global Ocean Energy Resources

• Theoretical Resources (TWh/year): Tides (300+), ocean waves (8,000-80,000), tidal currents (800+), temperature gradients (10,000), and salinity gradients (2,000).
• Estimated Global Electricity Production (TWh/year): Tidal (0.3K), Tidal Current (0.8K), Ocean Waves (8K-80K), Salinity Gradient (2K), and Thermal Energy (10K)
• Significant differences between theoretical resource potential and estimated production.

Specific Technologies and Examples

• Tidal Energy:
  • The Rance estuary near St. Malo, France, has the world's largest tidal power plant.
  • The Sihwa, South Korea, is the world's largest tidal power plant with a total power of 260 MW and an annual power generation of 543 GWh.
• Wave Energy: Different devices like oscillating water columns (OWCs) or various types of floating or submerged devices exist.
• Salinity Gradients:
  • Statkraft, Norway, has installed the world's first osmotic plant (generating 4 kW).
• Ocean Thermal Energy Conversion (OTEC):
  • A facility exists at Keahole Point, Hawaii.
• Ocean Thermal Energy Conversion (OTEC): demonstration of 1 MW device at Saga University, Japan, and a 30 kW OTEC system.

Explore the vast potential of ocean renewable energies in this quiz. Learn about various types of ocean energy, including tides, waves, and salinity gradients, and their technological applications. Understand how the ocean can contribute to sustainable electricity production globally.