There are things that electric power can’t do, like lifting this 787. But that doesn’t mean big jets can’t turn green, or at least greener. Several fuel refiners and airlines are experimenting with sustainable aviation fuels, known as SAF. These fuels, which burn like common “Jet A” fuel, can be made from wastes such as used cooking grease. Some companies, like Neste, use hydrogen to refine their SAF fuel.
Although aviation safety organizations allow commercial aircraft to use fuel containing 50% or less SAF, during demonstrations existing jets have burned 100% SAF, “and the engines are very happy with it,” Ms. Airbus Simpson.
But SAF can be seen as a stopgap, as bigger planes have flown happily, burning pure hydrogen with no emissions. In 1957, a Martin B-57B powered part of a flight using hydrogen as fuel. In 1988, a Soviet TU-155 airliner flew on hydrogen fuel alone.
For Senator Spark Matsunaga, a Democrat from Hawaii who died in 1990, it was a missed opportunity – as important as the Soviet satellite Sputnik beating the United States in space. “Once again, we have missed the boat,” he said, “and we can only hope that the next administration will be more interested in hydrogen than this one.”
Any mention of hydrogen powered aircraft means addressing the zeppelin in the room. Although hydrogen has been used in balloons since 1783, its aeronautical future darkened on May 6, 1937, when the Hindenburg Zeppelin very publicly burned down in Lakehurst, NJ, killing 36 people. It is still debated whether the flames, immortalized on radio and in the news (and a Led Zeppelin album cover), were caused primarily by hydrogen or the incendiary paint used on the airship’s fabric skin. Either way, the damage to hydrogen’s reputation persists today.
More recently, ZeroAvia experienced a bad news / good news scenario when its Piper Malibu Mirage M350 hydrogen fuel cell crash landed last April. The good news is that no one was injured despite the loss of a wing from the plane. Better yet, with no fuel leak and no hot engine to ignite it, there was no Hindenburg-type fire.
“The hydrogen system itself has held up perfectly,” Miftakhov said. “The emergency team said if it was a fossil fuel plane it would have been a major fire.”