Hydrogen as a fuel has many advantages — it can be burned instead of coal to produce heat, it can be run through electrolysers to generate electricity, and it can refuel cars as quickly as gasoline or diesel — but getting it to where it's needed is a challenge.
Hydrogen, the lightest gas in the universe, is hard to contain: it leaks through tiny cracks and seeps into certain metals, where it breaks down. Transporting it typically requires compressing it or liquefying it, both of which require a lot of energy. But there's an alternative: attach hydrogen atoms to carrier molecules that are easier to move around.
The idea is not new: So-called liquid organic hydrogen carriers (LOHCs) have been around for decades, and most of them rely on volatile organic compounds such as toluene or methylcyclohexane. These chemicals work well with hydrogen, but not well for much else, given their toxicity and the heat and pressure needed to release the gas.
A start-up called Airton Energy claims it has an alternative: LOHCs that can be transported and processed at room temperature and pressure, and that are non-toxic.
“It actually looks like water,” Airton Energy co-founder and CEO Natasha Kostenk told TechCrunch. “It's a safe, non-toxic liquid. You wouldn't drink it, but it won't kill you.”
Kostenk and co-founder Brandy Kinkead weren't looking to fundamentally change how hydrogen is transported: Their initial idea was to replace diesel generators with ones that run on clean hydrogen.
“We needed a hydrogen storage solution,” she said. “At first, we thought we'd just try to find one. We were going to integrate different things from the industry. But we couldn't find a hydrogen storage solution that made sense to us. So we came up with a solution.”
Kostenk wouldn't say which oils his company uses, but he said they store hydrogen in the same way that canola oil is turned into margarine, which is made from vegetable oils. Unlike the animal fats that make up butter, vegetable oils are liquid at room temperature. To make margarine, producers expose vegetable oils to hydrogen gas in the presence of a catalyst (a catalyst that speeds up the reaction). Once the oil is hydrogenated, it solidifies.
Ayrton is taking a similar approach. “It’s hydrogenation,” Kostenk says. “We’ve found a new way to do hydrogenation and dehydrogenation compared to traditional LOHC.” The equipment that adds hydrogen to the oil and releases it from the oil is similar to electrolyzers currently used to produce hydrogen from electricity. As a result, the company can use off-the-shelf equipment for much of its operation, and scaling up simply requires building more modules rather than larger parts.
Transporting Ayrton's oil wouldn't require anything special, either. “For example, those who already use liquid fuels can reuse a lot of that infrastructure: pipelines, rail cars, trucks,” she said. “I've talked to pipeline companies that have surplus lines that aren't being used, and they're looking for ways to reuse their old infrastructure.”
Kostenk envisions using tanker trucks to transport the hydrogenated LOHCs to industrial facilities. Once emptied, the tanker trucks would take the dehydrogenated LOHCs back to a processing plant so they can be reused.
Airton's process requires less energy for a round trip than liquid hydrogen, ammonia or methanol, and slightly more than compressed hydrogen, Kostenk said. But the advantage of LOHC is that it can carry twice as much hydrogen per liter as compressed hydrogen, and it has lower upfront costs because it can reuse existing trucks, pipes and pumps.
The company recently raised $6.8 million in a seed round led by Clean Energy Ventures and BDC Capital, with participation from Antares Ventures, EPS Ventures, SOSV, the51 and UCeed Investment Fund. With this funding, Ayrton plans to scale up its technology to produce 2-3 tonnes of hydrogen per day by 2027.