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Creating Energy from Water

Updated on May 10, 2013

The Basics - Hydro-Electric Energy

You might have wondered how energy can be created from water. Civilizations have been doing it for generations and with the advent of new technology it is quickly becoming cheaper and more efficient then ever before. In very plain terms here is how hydroelectricity works.

It starts by harnessing the potential energy of flowing water. As the water gets pulled downstream by gravity, it flows through the blades of a hydroelectric turbine. The blades are turned by the water which moves a turbine shaft that turns a generator rotor, and that creates electricity in the same manner as with other electrical generators.

What other was can water be used to create energy?

Power from the Ocean

There are a number of different ways energy can be created from the ocean today. One way that is currently being used in Portugal is called a "wave farm" This works by harnessing the potential energy from rolling waves offshore or near-shore. Essentially the rolling waves would cause buoys to sway back and forth. These buoys are attached to long shafts that reach the ocean floor. Connected to the shaft is a generator that is powered by the movement of the shaft, and this generator creates energy and then stores it back onshore via an underwater cable.

The possibilities of such power are really endless. Imagine seawater desalination powered by these wave farms. Nanofiltration could deliver clean water to entire cities at a very small energy cost. Or even with a membrane filtration system in your home you could still have clean water but powering other appliances could come from the wave farm energy.

Or rather than using waves there you could use the oceans natural currents. Water constantly moves around below the surface with these currents. The Idea is basically the same as the wave farm but with a different design. Here there would b no need for a long shaft but just blades that sway with the current. As these move back and forth they would generate the energy.

The Pros and Cons of Hydro-Electric Energy

Hydro energy's popularity continues to grow, but there are still some issues with its practicality. Here are some of the issues on both sides of the argument.


  • Hydro energy is free. You do not need to buy the water from rivers in order to use it to produce energy.
  • It is renewable. Whenever you use the water to produce electricity, it would be replenished by rainfall. This cycle goes on and on, making this source of energy renewable.
  • The moment that a dam is built, you could expect an abundant production of electricity, especially in areas where the river has a large water reservoir.
  • Dams are meant to last for a very long time. By building a dam, you are actually ensuring electricity production to last for years, up to the next generations.
  • Hydro energy production does not release greenhouse gases into the atmosphere. It is a clean form of energy that everybody could enjoy.
  • One advantage with a dam is that if electricity is not needed, you could just halt the production of electricity and save the water in the reservoirs


  • Cost. As with other types of renewable energy, the initial cost of the construction of the power plant is expensive, and dams are no exception.
  • Must be built with the highest standards. Dams should be built with precision, accuracy and with the right materials.
  • During drought or dry seasons, the water levels in the reservoir may decrease, which would affect electricity production.


Worlds First Wave Farm

A markerThe Aguçadoura Wave Farm -
Povoa de Varzim, Portugal
get directions

The Aguçadoura Wave Farm was the world's first wave farm. It was located 5 km (3 mi) offshore near Póvoa de Varzim north of Porto in Portugal.

How It Works

Pelamis in Action at Aguçadoura Wave Farm

One Type Of Wave Energy Converter


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    • ib radmasters profile image

      ib radmasters 5 years ago from Southern California

      I liked it, and I think it will be a perpetual source until the waves stop coming. It that happens, then energy will be the least of our problems.

      We can also use the power from the waves to support desalination for drinking water, and extracting Hydrogen for making fuel cells.


    • Patty Kenyon profile image

      Patty Kenyon 5 years ago from Ledyard, Connecticut

      Very Interesting information!!