Thermal energy storage is not new. Large-scale systems are commonly used and, if what you want back is heat rather than electricity, are very efficient. But, as you scale these systems down the efficiency decreases because of systems losses.
Some companies are now getting into the business of making home-sized systems. With close to 50% of home energy use in the US going to heating — space heating and water heating — it would seem that there is a place for such systems. Matt Ferrell takes you on a tour of what is available and when it can make sense. If may not be a replacement for your PowerWall, but it certainly could complement it.
