As we work to mitigate fossil fuels’ environmental impact, we’ve begun to explore many alternative fuel options: hydrogen, biodiesel, Martian soil, and even feces included. Another such option might be algae. United Airlines invested this week in a company set on making algae into fuel, generating hope that someday commercial flights might run more sustainably by way of aquatic protists.
United announced Monday that it had invested $5 million in Viridos, a California-based company working to decarbonize heavy transportation by swapping in sunlight and carbon dioxide for fossil fuels. Microalgae naturally convert light and CO2 into oil-rich biomass. Viridos’ biologists found in 2015 that microalgae could be genetically modified to produce more biomass and more oil, creating higher-yield algae. This is one major step toward scaling the production of algae-based sustainable aviation fuel (SAF) until it can be sold to commercial airlines.
Next on the priority list is cultivating enough high-yield algae to produce large quantities of SAF. Viridos grows its microalgae in shallow saltwater pools, erasing the need to use increasingly-scarce freshwater. The algae feed solely on sunlight and atmospheric CO2, allowing it to cultivate algae in nearly any climate—deserts included. Thanks to its small physical footprint, Viridos plans on building future algae farms exclusively in less desirable areas to preserve valuable arable farmland for conventional agriculture.
Two of Viridos’ algae pools.
“SAF is proven, scalable, and the best tool we have to reduce our carbon emissions from flying, but we face a significant shortage of available feedstock,” United Airlines Ventures President Mike Leskinen said. “Viridos’ algae-based biofuel technology has the potential to help solve our supply problem without the need for farmland or other agricultural resources.”
Viridos estimates that SAF produced with its algae will carry a 70% smaller carbon footprint compared with conventional fuel. That’s big news for United, which vowed to become 100% carbon-neutral by 2050 without using dubious “carbon offset” programs. The investment is part of the Sustainable Flight Fund, a $100-million pool fed by United and a few corporate partners. When United started the fund in February, it committed to investing at least 3 billion gallons of SAF. Spokespeople said that United had already “made investments in or signed purchase agreements” in companies using forestry waste, animal waste, and other undesirables to create SAF but didn’t specify which companies had benefited.
At the time of writing, neither United nor Veridos has said when the airline can be expected to use algae-based SAF on test flights.