An ambitious new project to create a “ground battery” has just been funded by the UK government. If it proves effective, solar energy could be stored in the ground in the near future.
The researcher in charge of the project, Dr. Michael Harbottle, for the first time had the idea of a battery "on the ground" by reading about a concrete battery. "If this thing uses a chemical process," he told himself, "what can we do by exploiting a biochemical process"? And he thought about bacteria.
How can soil store solar energy?
Harbottle's field of research is still abstract: but the English scientist he is not the first person to realize the potential of the soil. Sure, there are people who put soil in a jar, place two electrodes and prove that "there is something", but putting solar energy into the equation requires a different effort.
Plan? Sending electricity from the solar panels to the underground electrodes, thus stimulating some bacteria in the soil, which "eating" it to survive will somehow conserve it, converting it into acetate which powers “bacterial” batteries. Biochemical reserves of energy. Something similar to what we have also seen here, or here.
Could soil offer an alternative to lithium?
To say "soil" is to remain very vague. The soil is incredibly varied - take a spoonful of potting soil and you will find that it can contain more than 10.000 species of microbes. The researchers want to use some of the already existing organisms, selecting those that create optimal conditions for them.
“An advantage of the idea is that it does not require hazardous or resource-limited chemicals (like lithium) that are used in other battery technologies,” says Harbottle.
Acetate isn't harmful, but wouldn't produced in excessive quantities cause problems for other life forms? Harbottle acknowledges that it could. But they would be rapid systems, which do not accumulate energy for long: in the minds of the researchers, they would store it during the day to use it at night, that's it. This should avoid problems, but it is one of the things that will need to be tested.
What are the soil batteries used for?
For now, given the results, use in low power systems is plausible. Sensors, lighting systems, highway infrastructure and so on. Next, the researchers aim to join hundreds of cells together to produce a much higher voltage. Eventually these batteries on the ground could be installed just below the fields covered by solar panels. A perfect circle.
The pioneering aspect of this project highlights the ingenuity and imagination needed to overcome obstacles. I like. And it would be revolutionary. I will follow it very carefully.
