Storing energy is almost as important as producing it, because wind and solar have the property of being intermittent sources – either they produce in excess or lack completely. Molten salts are currently the most used solution for storing energy in the form of heat, but they sometimes tend to be expensive and not so efficient.
A team of MIT researchers have discovered and studied a molecule called fulvalene diruthenium (two aromatic carbon rings, attached to a transition metal). They found it has an interesting property of acting like a molecular heat battery, storing heat by changing its conformation and being pretty stable.
By applying additional heat or a catalyst, the molecule would then restore its original conformation, releasing the stored load. Professor Jeffrey Grossman, who led the team, said the compound “can get as hot as 200 degrees C, plenty hot enough to heat your home, or even to run an engine to produce electricity. It turns out there’s an intermediate step that plays a major role.”
The intermediate step hasn’t been revealed (yet), but Grossman says it makes the difference between the current experiment and the ones performed in the past, guaranteeing the success.
The base mechanism is very important to have been discovered, since it’s not Ruthenium that it’s going to be used in real life application, because it costs $650 for 150 grams, but some other molecules that could act in a similar manner.
Maybe heat batteries are not as efficient as lithium ions, but when it comes to storing energy for the grid, you don’t need mobility and hence increased costs. All that it’s necessary is something cheap and reliable and the system does what it’s supposed to. And, yes, there are those smart grid infrastructures that will evolve slowly, in parallel with electric cars.