In a first, a major airline will cross the Atlantic…

A Virgin Atlantic flight taking off this week from London to New York City will last about eight hours, span around 3,500 miles — and emit only a fraction of the planet-warming gases associated with a typical transatlantic flight.

On Tuesday, the British airline is set to pluck a Boeing 787 Dreamliner from its fleet and run the two powerful engines on 100 percent sustainable aviation fuel, or SAF, during the journey from Heathrow Airport to John F. Kennedy International Airport. If all goes to plan, Virgin Atlantic will be the first commercial airline to fly a passenger plane across the Atlantic Ocean by burning only fossil-free jet fuel, marking an important milestone for the CO 2 -intensive industry.

The flight will demonstrate ​“the longer-term potential of SAF to decarbonize aviation,” said Joey Cathcart, a senior aviation associate in the Climate-Aligned Industries Program at RMI, a clean energy think tank. (Canary Media is an independent affiliate of RMI.)

“This is really critical because SAF is the most readily available decarbonization mechanism that aviation has today,” he added. Cathcart, who is based in Salt Lake City, is slated to board the ocean-crossing plane tomorrow in London with a select group of passengers. ​“Confidence is high,” he replied when asked if he had any preflight jitters.

Globally, air travel accounts for about 2 percent of annual energy-related CO 2 emissions. As more planes carry more people, the industry’s climate impact is projected to soar by midcentury — the same time the world should be reaching net-zero emissions to avoid the worst damages of climate change.

Existing varieties of SAF are not entirely emissions-free, and supplies remain extremely limited across the industry. But as airlines face mounting regulatory and public pressure to decarbonize, sustainable aviation fuel is an appealing solution because it can work in existing fleets.

The category includes lower-carbon fuels made from biomass, such as cornstalks and forest residues, as well as inputs like hydrogen and captured carbon dioxide. However, nearly all the world’s existing supply comes from one particular type of fuel: hydroprocessed esters and fatty acids, known as HEFA, which is derived from pork fat, beef tallow and yellow grease collected from restaurants and industrial kitchens.

Virgin Atlantic’s plane will use 60 metric tons of SAF — a combination of 88 percent HEFA fuel and 12 percent ​“synthetic aromatic kerosene.” The latter is a compound derived from plant-based sugars that helps to lubricate jet engines and reduce fuel leakage around the seals.

The British airline said that SAF can reduce carbon dioxide emissions from flying by over 70 percent when compared to fossil jet fuel.

Virgin's July 2023 engine test using 100% SAF (Rolls-Royce/Getty Images)

The landmark flight arrives as airlines, fuel producers and policymakers worldwide are pushing to scale the production of SAF, including bio-based alternatives and next-generation ​“e-fuels.” Zero-carbon technologies are also in the works, with companies flight-testing planes powered by batteries and hydrogen fuel cells and designing liquid-hydrogen-fueled aircraft. But those solutions aren’t yet suitable for the most emissions-intensive kinds of flights — large planes traveling long distances — due to current weight, energy density and other limitations.

For those reasons, ​“We’re predicting that SAF is going to be the overwhelming majority of fuel used for long-haul flights in the 2040–2050 timeframe,” said Sola Zheng, an aviation researcher for the International Council on Clean Transportation, who is based in San Francisco.

Lots of demand, but little supply

Virgin Atlantic’s upcoming voyage will join a handful of recent initiatives seeking to prove that SAF can fully and safely replace fossil jet fuel on commercial flights.

Only a week ago, Gulfstream Aerospace said it successfully completed the world’s first-ever transatlantic flight using 100 percent SAF. On November 19, the U.S. aircraft-maker flew a G600 business jet from its headquarters in Savannah, Georgia to Farnborough, England. The demonstrator aircraft used only HEFA fuel and no aromatic compounds during the seven-hour flight, which carried testing equipment but not passengers.

World Energy, the fuel supplier, said its SAF reduces a flight’s life-cycle emissions by 83 percent.

Today, industry standards-setters limit the amount of alternatives that can be blended with conventional jet fuel, to ensure the new fuels are compatible with engines and fueling infrastructure worldwide. For instance, producers can’t use more than 50 percent HEFA in a given fuel mix. Virgin Atlantic said it secured special permits from aviation regulators in the United Kingdom, Ireland, Canada and the United States for its one-off demonstration flight.

An airport worker fuels a G600 jet with 100 percent SAF ahead of the November 19 flight. (Gulfstream Aerospace)

Yet even if the industry lifted its blending rules, airlines still couldn’t routinely fly on SAF alone. That’s because there just isn’t enough of the alternative fuel to go around.

In 2022, fuel producers churned out nearly 80 million gallons of SAF worldwide. Although that’s triple the volume produced in 2021, and while this year’s output is on track to ​“rise exponentially,” SAF supplies still represent less than 0.1 percent of total global aviation fuel. Where SAF is available, it can cost three to five times more on average than conventional jet fuel.

“Airlines are telling me they will take all my SAF, as long as it’s the same price as jet fuel,” said Gene Gebolys, president and CEO at World Energy. ​“But we can’t produce SAF at the price of jet fuel and have it be a going concern.”

World Energy is spending over $5 billion total to expand capacity at its existing SAF facility in Los Angeles and convert a biodiesel plant in Houston to make aviation fuel. To support those investments, the company recently signed long-term agreements with Microsoft and DHL Express, which are willing to pay a price premium to address their own air-travel emissions.

The two corporations aren’t directly buying fuel from World Energy. Instead, they’ll purchase certificates representing SAF that gets pumped into the larger supply chain — then count the associated carbon reductions toward their sustainability goals. Microsoft agreed to buy certificates representing 43.7 million gallons of SAF over a 10-year period, while DHL signed a contract for 177 million gallons over seven years.

The deals are priced based on every metric ton of CO2 avoided, and are both worth hundreds of millions of dollars, Gebolys said. He added that World Energy uses a digital registry known as ​“book and claim” to ensure the certificates are reliably and transparently tracked.