Abstract

The ocean covers 70% of the surface of the earth and holds 96% of all water. The evaporation provides water for the rain. The currents move the warm water from the tropics to Europe. The wind moves sailing ships, and drives wind turbines.

How can we capture this energy to create electricity to power our modern civilization? Let’s explore what is being done today and in the future to capture this energy.

What energy can the ocean supply

The ocean is a vast body of water that covers 70% of the earth surface. The water is more dense that air so the energy created by moving water has much more potential energy.

In another talk Power of the Wind, I talked about how the wind over the ocean can be used to sail ships, or power wind turbines. So I am not going to discuss the wind over the oceans. But for this talk I am going to focus on currents and tides.

Lets explore where this potential energy comes from.

What causes ocean currents?

Lets take some time to understand what causes ocean currents.

What causes ocean tides?

What is Marine Energy

Converting water movement into power

Ocean energy, also known as marine energy or hydrokinetic energy, is an abundant renewable energy resource that uses ocean water to generate electricity. The majority of ocean energy technologies are still in research and development. While the potential of ocean energy is great, it faces significant technological, environmental, and financial challenges and has low levels of investment.

There are four main types of ocean energy systems:

1. Tidal Barrage Systems are dam-like structures built across ocean inlets to form a tidal basin. Installed turbines inside the tidal barrage let water in to fill up the basin during times of high tide, and let the water flow out during times of low tide, generating electricity in both directions.

2. Tidal Stream (or Tidal Current) Systems use electrical generators installed directly into the stream of water, similar to placing wind turbines underwater. As water flows through the generators, they harness kinetic energy of the water and convert it into electricity.

3. Wave Energy Systems use the motion of waves to run a system that converts the mechanical energy of wave motion into electrical energy.

4. Ocean Thermal Energy Conversion (OTEC) takes advantage of the temperature difference between warm surface water and much colder water at depth to power a turbine in a closed-loop system that can generate electricity Ocean Energy

Tidal Systems

Lets start off seeing how tides can be converted into electricity.

We have seen three variety of tide power systems. Lets now focus on just one type of turbine, the Tide power turbine.

Wave Systems

Now lets take a look at different ways of using the waves to generate electricity.

Testing Wave Energy

The US navy has a facility to test different wave energy systems.

Generate electricity from warm water

Another way to create energy is using the temperature difference in ocean water.

Using a buoy to capture electric energy

Since the waves move up and down, why not use that motion to capture energy from the sea.

Where is Wave Power

So a final question, why aren’t we using more energy from the sea?

One answer are the upfront cost are much higher than current renewables. So the answer is investment in new technologies.

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Written by John F. Moore

Last Revised: Sat Aug 17 01:34:58 PM EDT 2024

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.