A new proposal to improve a 75-year-old dike, the Afsluitdijk, in The Netherlands could make it the world’s leading site for generating saltwater power— a clean, renewable energy source which is 30-40% more efficient than burning coal.
The breakthrough process, which is called reverse electrodialysis, captures the energy created when freshwater becomes saltier by mixing with seawater. Although scientists in the 1950s discovered that electricity could be generated this way, no one knew just how efficient the process could be until a recent study proved that a remarkable 80% of the energy could be recovered.
Just as it takes huge amounts of energy to desalinate water, energy is generated when the reverse happens, and saltwater is added to freshwater. Unlike hydroelectricity, where the energy from a surging river is evident to anyone sitting at its banks, the energy released at an estuary can’t be easily seen. Nevertheless, that power is there. If the proposed saltwater power plant is built on the Afsluitdijk, it could produce 300 megawatts of electricity. That could supply a large part of the electrical demand for homes in the northern parts of The Netherlands.
The Afsluitdijk is a 20-mile-long causeway which was constructed in part to dam off the Zuiderzee inlet of the North Sea, turning it into the massive freshwater lake of the IJsselmeer. The lake is periodically discharged since it is continually being fed by rivers and streams, which makes it an ideal location for the saltwater power plant.
The Netherlands is a country fighting for its life due to rising sea levels brought on by global warming. Most of the country is already below sea level, and studies have shown that as much as 65% of its land would already be submerged if not for their sophisticated flood control system. The system includes more than 10,000 miles of dikes and dams, as well as an elaborate structure of water pumps symbolized by the country’s iconic windmills.
Those symbols now represent the country’s dire need for a carbon-neutral world powered by renewable energy.
Image Credit: Johann H. Addicks on Wiki Commons under the GNU Free Documentation License
About Bryan Nelson
wonders of technology, We need these clean ways to make energy.
When I first read this article I was blown away!!!
Every river flowing out into the ocean could be a source of cheap energy!!!
But then I looked at your number, 300 megawatts.
Hopefully you mean that the causeway can generate 300 MW an hour. That’s the way the figures are usually used. And another thing the energy could be as regular as coal.
The thing I need is to tell me what does 300 Megawatts mean?
In Austin. Texas the average household burns approximately 10 MW a year.
So let’s do the math. 24 hours X 365 days X 300 MW
= 2,628,000 Megawatts!!!
At 10 MW per household that’s 262,800 households.
All I’m saying is that 300 Megawatts don’t mean anything to most people, I’ve asked people. And these are green people!
But when I say 300 MW, it means enough energy to provide electricity for a quarter of a million homes for a year. then that has meaning.
I just think the author has forgotten that most people don’t know what these energy amounts mean.
Another thing is how much land does a project of this size demand?
If it is too large it can’t be used all over the world but if it is small then maybe it could provide how much energy worldwide?
The big question here for me is can this be as big a deal as wind power?
If it is, Imagine how much energy the AMAZON RIVER could create!!!
Best wishes.
Robert,
You’re right to be excited about the potential of saltwater power. In some circles, this method is actually being called “Blue Energy”. Some predictions suggest that the entire Rhine estuary in The Netherlands could supply 1 GW of energy, which would power around 650,000 homes. In fact, if all of the river estuaries in The Netherlands were fully tapped, the energy generated could supply as much as 75% of all of the country’s needs.
Of course, there are limits. Blocking off an entire estuary to control for salinity energy will have other huge negative environmental effects which must be considered. Energy production at those levels wouldn’t be feasible– but imagining the potential is exciting. In areas like at Afsluitdijk, where a massive dike infrastructure already exists, there’s no reason not to take advantage.
So to answer your primary question: Yes, it means 300MW per hour– at full capacity. Like with wind turbines, the plant can’t always operate at consistent capacity. It depends upon salinity levels, water flow, etc. But this blue energy is still far more reliable than wind– top capacity for saltwater energy can be reached twice as many hours per year as opposed to wind energy.
For more details about the process, I’ll refer you to an article on the topic done by New Scientist, which can be found here:
http://www.newscientist.com/article/mg20126972.000-salt-solution-cheap-power-from-the-rivers-mouth.html?full=true
I discovered that link after publishing the article, so I didn’t link to it in the article– but it’s a helpful resource that should help answer some more of your questions.
And yes– imagine the Amazon.
what a terrible idea. In a few years, fresh water will become a rare resource; why waste it to create energy?
We have many coal and oil alternatives, like wind and wave power. But there are people who make big OIL money and they will do anything to stop Green energy.
The phrase “MW per hour” is meaningless. The watt is the unit of power, so the output of a power station is measured in watts (more usably, megawatts or gigawatts).
Energy, which is what you pay for, and whose consumption you are concerned about, is measured in various units, but the one in which electricty for consumption is metered is the watt hour, which is the consumption of 1 watt for 1 hour. The commonly used unit of billing for domestic consumers is the kilowatt hour. A 300MW power station produces 300,000 x 24 x 365 = 2,628,000 kwh per year (assuming continuous full output, which won’t happen) hence the figure of 262 households given average annual household consumption of 10,000 kWh.
300MW per hour makes no sense, a watt is a measure of power, that already takes time into account, ie 300MWatts = 300Mjoules per second.
Watts means joule/second so saying megawatts/hour does not really mean anything.
About the potential: this is going to be a pilot project, and really, this is no large-scale energy solution. The membranes are expensive, get polluted, and can only have small throughput.
There are a few missing important pieces of information, like how much fresh water does this process consume for a given output, and how pure does the fresh water have to be? I am also curious as to the size of the generating facility and how expensive it is to set up.
iceanfire, maybe you didn’t read the article? This has nothing to do with freshwater and would in no way affect the world’s supplies even if it did.
This page has send more then 50 cookies. On dialup it took a long time to load. Not all of us are adsl enabled. However, content is great,
John
We do need to replace coal throughout the world with more efficient means and it looks like a way has been found.
yeah i agree this is a great idea but needs more facts / how exactly it works
Kindly folk from Texas seem to equate electric consumption in Texas with that of the rest of the world, then assume they will be able to continue living at this consumption level forever, or that it is and “Entitlement”for all of humanity! It is not! Outside of the xenophobia of Americans, folks live on much less, Take the Super-Insulated, Straw Bale Home dwellers of Northern Canada, who at 40 degrees below zero,Celsius, and northern latitudes, successfully solar heat through superior Canadian technologies! Realize that power consumption the world over is lower than for Americans and their very shabby technologies where power is concerned! Sweden is a good place to start a web-study, then take the average Norwegian into account! Few of the peoples on the earth are as energy dependent, vulnerable, and require the power Americans do just for survival!