Here at AboutMyPlanet.com, we cover a staggering amount of alternative energy sources. If I draw a timeline of new developments in this field, I am sure it would look like a stock market graph. To add to all that’s happening here’s another one from Germany.  A group of scientists working for the German group, Solar Millennium AG are trying out a markedly different way to produce solar energy. What’s ‘markedly different’? Well, this time around the research has yielded a way to produce energy from the sun even when the orb isn’t shining.

Solar Millennium AG, an international installer of solar thermal plants believes that this is a pathbreaking effort.  The pilot plant in Spain called Andasol 1 is currently the epicenter of this revolutionary new process.

The secret behind the solution...

The process relies on the melting point of a very common compound – Salt. Yes, the very thing which sits on our kitchen table; though, not the exact kitchen variety.

The energy storing process uses the high melting point of salt as a way to store energy. Usually, salts have very high melting temperatures and do not turn to vapor until the temperature is very hot. Table salt has the melting point at 1452 degrees Fahrenheit or 800 degrees Celsius. So it can easily be used to store heat from the sun.
 
Many salts though have lower melting points than the common salt and low densities. The researchers thought of exploiting this property and use salt as the principal heat carrier in place of oil as is the favored method. Oils break down above 750 degrees while melted salt requires much higher temperatures. Also, the more temperature molten salt takes on, the more efficient it becomes.

How does it all come together?

Using a combination of 60-percent sodium nitrate and 40 percent potassium nitrate, ‘Andasol’ salts are melted at 430 degrees Fahrenheit and stored in an insulated tank at 550 degrees. This pre-heated salt is then pumped to the top of a tower fitted with another tank called a receiver, where the sun heats it to 1,050 degrees. This heated, molten salt flows back down to a second insulated storage tank, and can be used on cloudy days to drive a steam turbine.

Here are the clinchers...

The use of salt allows the generating plant to run high efficiency (50 megawatts) for almost 8 hours after the sun has set.

The salt process is 93-percent more efficient than using solar panels to convert sunlight into electricity.

For residential use, cooled salt from the turbine could also re-used to generate heat for a heating system.

That this salt-solar concept is truly a pathbreaker can be noted from the fact that a lot of planned solar plants are looking to take in this technology. Perhaps for the over-arching reason that the energy remains safe, clean, efficient and finally is not tied to the setting sun.