Ants! Run for your lives! Or, perhaps, are ants the key players in the Hydrogen Economy?

Although they will not know it, when the world finally moves off petroleum completely, we may have the ants to thank.

Formica, as ants were known by the Romans (yes, formica, but not the flooring material) — when squashed, emit a characteristic odor and that’s formic acid.

That we know so much about it is thanks to the fact that medieval chemists had access to so many ants. Says something about the connection between sanitation in the Middle Ages and the cause of innovation.

So, here’s the thing. Could be that formic acid provides a vital energy storage medium for hydrogen. when H2 is used for transportation fuel.

Hydrogen’s appeal

And there’s a reason that hydrogen is getting so much attention, of late. Not just because it offers possibilities beyond petroleum.

You can travel roughly 50 miles on a kilo of hydrogen fuel, according to Toyota and based on its hydrogen fuel vehicle. The Chevy Equinox averages roughly 45. That’s about four times as far as you can travel on a kilogram of diesel, even in a lightweight vehicle. Almost 6 times as far as a kilo of gasoline can power a standard intermediate passenger vehicle.

Hydrogen’s problem

So, that’s good. But how do you store and deliver the hydrogen?

As this article notes, Storage and transportation of hydrogen is a major obstacle for its use as a fuel and this one adds that “practical hydrogen storage systems use pressurized bottles or cryogenic conditions”.

The Formic Acid, er, solution

Hold off spraying that can of RAID just yet. The ants provide us with a solution. Researchers note that “formic acid has a volumetric hydrogen density of 53 g of H2 per liter, a low-toxicity and is a liquid under ambient conditions, it is an ideal hydrogen storage material for certain applications.”

Bottom line, a 12 gallon tank would, under ambient pressure (around 15 pounds per square inch) hold around 2.5 kilograms of hydrogen, enough to power a vehicle 125 miles. And there’s a lot of room to dramatically increase that range.

How do you get the hydrogen into and out of the formic acid?

Chemically, the idea is simple. Add hydrogen to carbon dioxide and, presto, you have formic acid. And vice-versa. And it hasn’t been a huge challenge to separate the hydrogen out of the formic acid.

However, the trouble has been in finding catalysts that can readily overcome CO2’s thermodynamic stability, make formic acid from hydrogen and CO2 . Platinum catalysts just haven’t been working.

But this research team has found success with a ruthenium-based catalyst.

More about advances in formic acid here, here and here.

The Concept Car

A team of young scientists at Eindhoven University in The Netherlands have gone a step beyond. Based on what Phys.ORg described as “a chemical reaction, discovered last year by TU/e researchers [that] enables hydrogen and CO2 to be converted at high speed into formic acid, and vice versa,” they’ve gone and build a scale model of a vehicle.

Here it is.

Photo by Bart van Overbeeke

The Whyfore

Basically, a hydrogen car in an electric car, without the heavy, expensive and inefficient electric batteries. You get the efficiency of the electric motor, combined with the efficiency of liquid storage of energy. We profile the appeal and technologies associated with hydrogen fuel-celled vehicles here.

What’s new here?

Bottom line, hydrogen infrastructure is tough. There are a handful of hydrogen refueling stations; they can cost up to $1M each. Basically companies like Toyota have been counting on friendly governments to build them as a gift. California has been enthusiastic, but progress has been slow.

So, the opportunity to bypass the hydrogen transport and storage problem via formic acid is very tempting. The car loads formic acid, converts into H2 and CO2, and goes.

Some limitations to consider

One, the fuel cell uses hydrogen, so a reaction takes place to separate formic acid into CO2 and hydrogen. If one doesn’t capture the CO2, it’s emitted. And when refueling with more formic acid, the CO2 will have to be safely disposed for recycling.

Second, the system is at model scale. Although as Phys.Org reports, “In 2017 Team FAST wants to have built the world’s first car powered by formic acid. They will do that by converting an existing hydrogen-powered car…Before the year is out they hope to demonstrate the concept in a bus.”

Third, the range is not yet impressive. 125 miles will induce the same range anxiety that plagues electric cars — even if carrying some 120 pounds of liquid fuel is a lot more sensible than carrying a 400 pound electric battery.

Fourth, formic acid is highly corrosive, and standard tanks designs are not appropriate.

The Bottom Line

The world needs denser energy carriers. Hydrogen is better than electric batteries. Will formic acid prove the bridge between liquid energy storage and electric motors? Stand by as this story continues to unfold.