It isn’t strictly solar, or at least not the solar we’ve gotten used to (solar PV or thermal), but researchers at MIT have discovered a new way to store the sun’s heat and release it on demand. Its name? The thermo-chemical approach.

mit solar storage 

Experiments show that the process could produce temperatures up to 200 degrees, which according to Jeffrey Grossman, Associate Professor of Power Engineering at MIT, is “plenty hot enough to heat your home, or even to run an engine to produce electricity.”

According to Grossman, thermo-chemical approaches to storing the sun’s heat as energy are an improvement over existing solar thermal technologies because the process is reversible, it is stable over a long term, and it can be used where needed. In fact, Grossman notes, we could put a container of fuel near the sun, heat it up, then use the heat and return the same fuel to the sun again to recharge it.

The process was initially investigated during the dual energy crises of the 1970’s (the oil crisis in 1973 and the energy crisis triggered by a revolution in Iran in 1979). Later, the investigation was dropped because no one knew of a chemical that could reliably store energy.

Then, in 1996, fulvalene diruthenium was discovered, and it had the precise heat-trapping characteristics needed. Unfortunately, ruthenium was, and is, too costly to use in the everyday world. Over the last month, it has spot-traded at a high of $185 per ounce and a low of $175.

Now, armed with vastly improved technology that has determined that ruthenium’s heat stability is actually part of a two-step process, and armed with a database showing the characteristics of “tens of millions” of known molecules – one or two of which might substitute for ruthenium at a more reasonable cost, researchers hope to move thermo-chemical into the mainstream of solar energy technologies.

Of course, it’s still in the R&D stages, but at the rate new technologies move forward, thermo-chemical fuel cartons for your forced-air furnace could be right around the corner, especially with funding from the National Science Foundation and an MIT Energy Initiative grant.

Photo Credit: Toshihiro Oimatsu via Flickr CC