Can air travel ever be green?

Exploring the innovative technologies being developed to make aviation greener and air travel less polluting | By Ryan Gardiner

Can air travel ever be green?
Photo by David Kovalenko / Unsplash

We are already seeing advances in the move to make aviation greener, with the introduction of a new generation of aircraft that use 20% less fuel per passenger than existing ones. But what if we could fly without the huge carbon footprint that comes with it?

In the last few years, several new technologies have emerged, including a successful trial in the use of 100% sustainable aviation fuel (SAF) by a long-haul commercial airliner. Estimates suggest that SAF could contribute roughly 65% of the reduction in emissions needed by aviation to reach net zero by 2050.

The fuel, which is a mix of animal fats and cooking oil as well as other components, was used on a Virgin Atlantic flight between London and New York in November 2023. 

Virgin stated the aim is “to demonstrate the capability of SAF as a safe drop-in replacement for fossil-derived jet fuel, compatible with today’s engines, airframes and fuel infrastructure”.  

Although only a single flight, with the technology being in the trial stage, it is an important step forward in advances towards cleaner air travel.  The net emissions from the Rolls Royce-powered engines on the flight were roughly 70% lower than the average non-SAF equivalent.

Greater use of SAF could still be an important step for the aviation industry, with it giving a reduction of about 80% in carbon emissions over its lifecycle compared to normal jet fuel. But a reduction in production costs and increased investment are needed to make it really take off.

But although SAF production has already tripled since 2021, and with BP planning to increase production to 100,000 barrels a day by 2030, its potential remains very limited, accounting for just 0.1% of current aviation fuel usage.

So what other options are there?

Electric planes were once seen as the natural successor to the modern-day jet. And there are several new developments underway, including NASA’s venture with Boeing to produce a small-to-medium-sized plane that could travel between New York and cities in the midwest of the United States. However, technological and regulatory barriers remain high, making the production of battery-powered passenger airliners highly ambitious. Large electric passenger jets are still decades away, according to most forecasts. 

Hydrogen-powered aircraft appear to be a more realistic option, with UK operator easyJet working with aircraft engine-maker Rolls Royce on a hydrogen aircraft capable of carrying 200 passengers by 2035.  Aircraft manufacturer Airbus is also working on developing a hydrogen-powered plane. 

Our gradual shift towards renewable energy will mean that sources such as wind and solar power will allow green hydrogen to be produced at a larger scale. The use of green hydrogen to generate electricity emits only water and warm air, meaning it is cleaner than burning liquid hydrogen which emits small amounts of nitrous oxide.   

Green hydrogen appears to be more of a viable option in reducing greenhouse gas emissions for short-to-medium haul aircraft, in contrast to electricity, which has high initial costs and still depends on the slow recharging of batteries.

Airbus believes that if we can produce engines that use hydrogen fuel cells to generate electricity, it could have a 100-seater aircraft capable of travelling 1,000 miles in service by 2035.

Words by Ryan Gardiner