Kent Nguyen

I met Kent through a colleague that I had designed some hardware for. He mentioned that he had been designing sand batteries for the last few years. You can read the full story on his blog.

Sand batteries are a type of thermal battery. You heat up a lot of something and insulate it very well. Then you recover that heat later when you need it. There are a few cases where this is a very efficient thing to do:

  1. Solar power, so you can cheaply store energy for later.
  2. Industrial processes that both produce heat and require heat -- but at different times or places.
  3. Agriculture, where you may need a heat source far from electricity.
  4. Power grids where a premium is charged during periods of high load.
An early prototype of Kent's sand battery, from 2022. Photo courtesy of Kent Nguyen.

Sand batteries are not just made with sand! It's important that they have a high thermal mass, be stable at high temperatures for long periods, and be possible to move around. Sand is just component, there's a lot of R&D to determine an optimal heat carrier.

This is what Kent has been up to for the last 3 years -- and he's delivered a working product, and designed a factory to produce it!

Note that a sure-fire way to get me to leave the comfort of home is to offer me a tour of a factory! I don't have any photos of the factory, but it was a large warehouse just out of town. I got to see a sand battery under construction. It was much larger than the prototype, easily the size of a shed. The economics of sand batteries improve with size -- the amount of thermal energy that can be stored increases to the cube of the linear dimensions, but the surface area (and thereby heat loss) increased by the square. It's nice when exponential laws work in our favor!