E very now and then you come across something that takes your attention. What Swedish start up SaltX is doing, is one of those times. Their concept of using modified salts to store and release energy could be a global game changer. So far, their pilot test bed, run from a German power plant, has been a major success.
Right now, we cannot effectively rely on energy from solar and wind, to produce a continuous power stream. Tesla batteries have proved they can help stabilise power grids in SA, but this is only on a limited scale. If SaltX’s process proves itself, then the system will overcome a major problem in catering for these fluctuations. Using this, it can safely and effectively store energy from wind and solar, while giving a stable energy source. This could in fact, be a big factor in removing reliance on fossil fuels. They call it “thermo chemical storage”, another way to describe it would be as a ‘heat battery’.
The firm’s focus now is on utility scale solutions, but this idea could see it in residential situations too. SaltX has partnered with Vatenhall, who operate the Reuter Power Station in Berlin, to pilot their concept. The power station supplies around 600,000 households with heat. In Germany, they use about 50% of their power on heating. The SaltX concept is ideal for this kind of situation, as are many other places around the world.
The process uses chemically treated salts to store energy, but how does it do this? Firstly, the salts are in a water suspension. When they heat this mix, which is much like in an oven, it absorbs the energy and stores it. It drives off the water in the process. What happens next is amazing.
The water that boils off is put back in the now dry salt, and in doing so release the energy. In doing so, a vigorous chemical reaction takes place giving off a lot of heat. The process is like a closed loop, so there are no emissions, just heat. The researchers found that the salt crystals tend to bind together and enlarge over many heating / cooling cycles. To stop this they put a nano coating on the crystals so they cannot stick to each other.
By coating the salts, they also stop the particles from coming into direct contact with other surfaces which prevents rust. This technology can use various salts. The type of salt mix in use at the Reuter test plant is calcium oxide.
Germany has enough renewable capacity to make twice as much power as it needs. But the problem is that it is not constant and they cannot store this energy. The SaltX concept allows them to hold that power in store, for short or long periods. Then they can release it as they need to, at anytime. If this concept works, then there would be no need for a fossil fuel back up either.
This simple process can absorb 10x more heat than water. They can store the energy rich salt at room temperatures. The salt does not give off heat energy like hot water. And as the process traps the energy within the salt - you want heat? Just add some water! The heat given off can reach temperatures of 450°C.
The Berlin test plant can supply heat up to 100 homes, but SaltX say they can easily scale it up. The high temperatures that can be attained could also have use in the food preparation industry too. As the salts are not toxic, and can be obtained sustainably, this also gives advantages over other technologies. Many also use toxic or rare materials as well. So far the program has been successful but time and more testing will tell if it’s an energy “Holy Grail”.