There are some things that electrical power cannot achieve, like lifting this 787. But that doesn’t mean that big jets can’t get greener, or at least greener. Several fuel refineries and airlines are experimenting with sustainable aviation fuels called SAFs. These fuels, which burn like the usual “Jet A” fuel, can be made from waste such as used edible fats. Some companies like Nests, use hydrogen to refine their SAF fuel.
Although flight safety organizations allow commercial aircraft to use fuel with 50 percent or less SAF, existing jets in demonstrations have burned 100 percent SAF, “and the engines are very happy with that,” said Ms. Simpson of Airbus.
But SAF can be seen as a stopgap measure, as larger planes have happily flown burning zero-emission pure hydrogen. In 1957, a Martin B-57B powered part of a flight using hydrogen as fuel. 1988, a Soviet TU-155 aircraft flown on hydrogen alone.
For Senator Spark Matsunaga, a Hawaii Democrat who died in 1990, this was a missed opportunity – as significant as the Soviet Sputnik satellite that launched the United States into space. “We’ve missed the boat again,” he said, “and we can only hope that the next government will be more interested in hydrogen than this one.”
Any mention of hydrogen aircraft means addressing the zeppelin in space. Although hydrogen has been used in ballooning since 1783, its aeronautical future clouded over on May 6, 1937 when the Hindenburg Zeppelin burned very publicly in Lakehurst, New Jersey. It is still debated whether the flames, immortalized on the radio and in newsreels (and a Led Zeppelin album cover) were mainly caused by hydrogen or the burn paint on the fabric skin of the airship. Regardless, the damage to the reputation of hydrogen continues to this day.
More recently, ZeroAvia experienced a bad / good news scenario when its hydrogen fuel cell powered Piper Malibu Mirage M350 crashed last April. The good news was that even though the plane lost a wing, no one was injured. Better still, since no fuel could leak and no hot engine could be ignited, there was no Hindenburg-like conflagration.
“The hydrogen system itself held everything perfectly,” said Miftakhov. “The rescue team said if it was a fossil fuel airplane it would have been a major fire.”