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What is Blue Energy?


Blue energy, sometimes called ocean energy, is a term for the method of generating electricity through the convergence of both fresh and salt water. This energy can be extracted through a variety of means, including tidal power, current power, wave power, thermal energy conversion, and osmosis. Power may also be collected by harnessing the wind power associated with the body of water — usually the ocean.

A type of blue energy extracted by osmosis, also called salient gradient power, employs a large artificial semi-permeable membrane to create reverse electrodialysis from natural marine resources. The energy that results can be used to generate electricity. The only byproduct is brackish water. Brackish water is simply a combination of fresh and salt water which naturally occurs in an estuary.

Blue power is energy that is harnessed from the natural movements of the oceans.
Blue power is energy that is harnessed from the natural movements of the oceans.

This type of energy is only useful in certain geographical areas. The only way to create blue energy other than in a laboratory is at an estuary, where fresh water river currents and the saline tides of the ocean meet at the river’s mouth. Though the technology has been understood for quite sometime, manufacturing the membranes was far too expensive to become a practical energy alternative. Recently, more economical membranes have been developed which will allow blue energy technology to begin being implemented in suitable environments.

In addition to blue energy as it relates to reverse electrodialysis, there is also a company called Blue Energy. This company also provides alternative energy but their technology is slightly different. The power generated by the company harnesses the currents of the ocean’s tidal waters using a turbine. The turbine is similar to a windmill except that it works underwater. Harnessing ocean currents is more efficient and predictable than wind power, so it is a good solution for seaside communities.

The environmental benefits of the company as well as blue energy are invaluable. Since both technologies are renewable and do not emit greenhouse gases, the use of this energy where possible will help to reduce global warming and other consequences caused by burning fossil fuels. In addition, blue energy does not take up a lot of space like energy grids do, and ecosystems are not negatively affected as they are with mining and drilling for example.

Frequently Asked Questions

What exactly is blue energy?

Blue energy, also known as osmotic power or salinity gradient power, is the renewable energy generated by exploiting the difference in salt concentration between seawater and freshwater. When these two types of water mix, such as at river mouths, energy can be harnessed through processes like reverse electrodialysis or pressure retarded osmosis, converting the salinity gradient into usable power.

How much potential power can be generated from blue energy?

The global potential for blue energy is significant, with estimates suggesting that the energy available from the salinity gradients at all the world's river mouths could produce about 2 terawatts of electricity, which is roughly 13% of current global energy consumption, according to research published in the journal "Renewable Energy".

Is blue energy a widely used source of power today?

As of now, blue energy is not widely used. It remains in the experimental and pilot project stages, with the world's first osmotic power plant opened by Statkraft in Norway in 2009. However, it has not yet been scaled up to widespread commercial use due to technological and economic challenges that are still being addressed.

What are the environmental impacts of blue energy?

Blue energy is considered environmentally friendly because it produces no greenhouse gas emissions and has a minimal ecological footprint. The technology operates silently and is unobtrusive, with no need for dams or barriers that can disrupt marine life. It's a clean energy source that leverages a natural process, thus having a low environmental impact.

Can blue energy be used in conjunction with other forms of renewable energy?

Yes, blue energy can complement other renewable energy sources like solar and wind, which are intermittent. Since the mixing of freshwater and seawater is a continuous process, blue energy can provide a more constant power output, potentially stabilizing the energy grid when combined with other variable renewable sources.

What are the main challenges facing the development of blue energy?

The main challenges for blue energy include the development of cost-effective and durable membranes needed for the energy conversion process, scaling up the technology for commercial use, and optimizing efficiency. Additionally, finding suitable locations for plants that have minimal impact on ecosystems and local communities is also a challenge that researchers and developers are working to overcome.

Discussion Comments


@behaviourism, it does seem like many renewable energy sources are not considered because they are not profitable. I hope that blue energy can at least become a good source of energy in the geographical regions for which it is best suited, through small business or community outreach if nothing else.


It is interesting that in all of the recent energy news popping up, there has been almost no talk of blue energy. I imagine part of this is because no one has found a good way to copyright it or otherwise extort it. That seems to be the best way to get attention for energy sources these days.


So blue energy is truly "green energy", since no pollutants come of it.

Is the cost of the membrane the ONLY reason we don't use blue energy? If the membrane is that expensive why haven't more tidal turbines been utilized?

The article doesn't say if the turbine in tidal waters uses the membrane too.

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    • Blue power is energy that is harnessed from the natural movements of the oceans.
      By: EpicStockMedia
      Blue power is energy that is harnessed from the natural movements of the oceans.