Short CO₂ supply may complicate COVID-19 vaccine rollout

The world got good pandemic news for a change when COVID-19 vaccines from Moderna and from a collaboration between Pfizer and BioNTech showed promising results in late-stage clinical trials. Moderna’s vaccine needs to be shipped and stored at –20 °C, which most conventional freezers can achieve. But the Pfizer-BioNTech vaccine needs to be at –70 °C, which is best done with dry ice. And therein lies a problem.

Dry ice is made by compressing and cooling liquid carbon dioxide. It accounts for about 20% of US demand for CO₂. The trouble is, CO₂ is in short supply. Most CO₂ in the US is captured from ethanol and ammonia production, both of which are down right now, explains Jeff Holyoak, vice president of market development at the dry ice equipment maker TomCO₂ Systems.

Depressed ammonia prices in the US have led to plant shutdowns, Holyoak says, and weak demand for fuel ethanol has many plants idle. On top of that, demand for dry ice is already up because of an increase in home delivery of frozen groceries. “There’s certainly a lot of fear in the market right now,” he says.

Josh Pringle, vice president for business development at the instrument maker CO2Meter, agrees that CO₂ supply is tight. “The analogy I always use is pizza. At some point, you just can’t cut the pizza into any smaller slices. The only way to keep everyone happy is to make a larger pizza. Right now, they can’t make enough CO₂.”

The ethanol industry is recovering, says Geoff Cooper, CEO of the Renewable Fuels Association, an ethanol trade group. But it is still capturing 25% less CO₂ than it was this time last year. Not all ethanol plants capture their CO₂, Cooper says, so creating incentives for them to do so could alleviate the problem while also addressing climate change concerns.

Holyoak says the shortage is also an opportunity to start capturing CO₂ from large heating systems, landfills, and incinerators. “The technology is all there,” he says, but “the cost structure has been a little tight, the tax incentives have been a little tight.”

Airgas and Reliant, two major providers of CO₂, are telling customers they can cope with new demand related to vaccine shipment. And the dry ice industry expects to be ready to compress and deliver the gas. Stephanie Mueller, dry ice supervisor for CryoCarb, says her firm is doubling its dry ice production equipment and tripling its liquid CO₂ storage capacity to get ready for the surge in demand, and she says competitors are making similar moves.

Holyoak agrees, saying that 2020 had already been a stellar year for TomCO₂, and that equipment orders are getting even stronger as Pfizer, UPS, and other companies gear up to make their own dry ice.

William Pressey of the dry ice distributor Arizona Iceman expects some disruptions over the next few months as the market adjusts. Pressey suggests that scientists and businesses that rely on dry ice or other forms of CO₂ get their orders in soon and plan for longer wait times. In the long term, “we’ll work out the supply and delivery,” he says.