Ever hear of a 'Sand Battery'?

One of the biggest questions surrounding the variable technologies like wind and solar is how to get power steady through a 24 hour day when the ‘fuel source’ (wind or sun) comes and goes.

One of the most frequently heard solutions is chemical battery storage. Rechargeable batteries that get charged up when the system is making excess power and then discharge later on when there is less (or zero) power production.

For many, chemical batteries present a few troubling issues that can be hard to come to terms with. The ‘rare earth’ minerals are not unlimited and are often strip mined which deeply impacts the local terrain. (Not to mention the subject of child labor in some of the mines)

Then there’s the question of safety. Some rechargeable batteries have caused enough problems that airlines will not allow them in checked luggage. While this has been (mostly) addressed by improvements to the batteries, a battery fire is incredibly hard to put out- especially on a utility scale type installation.

There are other methods of storing the excess energy. One very popular method is pumping water from a lower to an upper reservoir and then porting that water through turbines to produce power later on when it is needed.

That brings me to the newest (to me) technology that seems not only very interesting, but very promising- at an incredibly affordable cost…

Sand Batteries.

First- these probably are more better suited to cold climate areas and are not likely to be a universal solution for storage of power once it has been made.

That said, here’s how they work.

- Imagine a huge grain silo filled with sand that has a complex maze of piping in it. Extremely hot air is circulated through the piping which heats the sand to temperatures approaching 1000F.
- The sand holds that heat very well because the silo is extremely well insulated.
- Wind and/or Solar power provides the electricity to run heaters and blowers to get that hot air circulating and heat up the sand.
- Later, when it is cold- blowers circulate air through the sand and heat it up, and that hot air is then distributed like normal centralized steam heating systems to buildings.

What’s really interesting is all of it is existing technology essentially. There’s nothing exotic about electric heaters, blowers, piping, hot air distribution, etc. And there’s nothing really exotic about the sand, either.

Trouble is, this ‘storage’ system stores heat, not usable electric power. It supposedly can be outfitted with a steam system to turn turbines and make power- but the efficiency drops to incredibly low levels.

The efficiency of the system is very high due to direct conversion of the power from wind or solar to heat (think of heater elements in a toaster), the heat storage capacity of the sand, and the insulation of the sand ‘silo’.

Scope out the Sand Battery here:
https://www.youtube.com/watch?v=G6ZrM-IZlTE

All of this promises to expand the usefulness of wind and solar into current use of energy which can reduce the burden on the grid and possibly provide alternative power sources which (hopefully) has the net effect of lowering overall power costs.

The future is bright for wind and solar!

If you are considering rooftop solar, I have a book coming out soon that I think might help you quite a bit. Click here to get notified when I release Tucson Solar Insider Desk Guide for Buying Solar.

Be Good!
Curtis