Hydrogen-powered aircraft could soon revolutionize short-haul air travel, as researchers are predicting commerical fossil-fuel-free flights will take off within a matter of years.
According to the team, the new generation of planes could fly journeys of up to 750 miles without needing to refuel.
Based in Sweden, the researchers noted that their bold new framework for sustainable travel could meet the needs of 97 per cent of all intra-Nordic flight routes by 2045.
Researchers at Chalmers University have developed a mechanism that stores hydrogen at blisteringly cold temperatures without impacting engine heat.
The first flights of this kind could depart as soon as 2028.
"If everything falls into place, the commercialisation of hydrogen flight can go really fast now. As early as 2028, the first commercial hydrogen flights in Sweden could be in the air," said turbomachinery specialist Tomas Grönstedt in a statement.
Low-carbon produced hydrogen's implementation into aviation would mark a useful step in reducing the carbon footprint of the industry. Between 1990 and 2019 the amount of carbon dioxide produced by air travel doubled from 0.5 billion to 1 billion tonnes.
Hydrogen contains more energy per pound than today's kerosene. It also benefits from the residual product of combustion being water vapor, rather than harmful pollutants.
However, much of the ongoing work by Grönstedt and his team examines the material considerations needed to ensure the transition works effectively.
Aircraft manufacturers will continue to use present-day turbofan engines despite the change in fuel. This will make the transition to cleaner energy smoother, and at a lower cost. This decision comes at a different price—new technologies, like advanced heat exchangers need to be developed to make hydrogen more efficient.
Conventional turbofan engines are designed to use kerosene, which is stored at ambient temperatures and combusted at high temperatures. Hydrogen must be stored in liquid form, supercooled around -418°F (-250°C), to maintain lightweight fuel systems.
The team developed a completely new kind of exchanger, patent pending by partner GKN Aerospace. This technology uses hydrogen's low storage temperature to cool engine parts and utilizes waste heat from exhaust gases to preheat the fuel before combustion.
A higher efficiency heat exchanger provides better flight range for each sustainable aircraft.
"Every degree increase in temperature reduces fuel consumption and increases range. We were able to show that short- and medium-haul aircraft equipped with the new heat exchanger could reduce their fuel consumption by almost eight percent," said Carlos Xisto, a specialist in fluid mechanics at Chalmers, in a statement.
"Considering that an aircraft engine is a mature and well established technology, it is a very good result from a single component."
Although there will be challenges in advancing this technology, the team is on fertile ground, operating on a budget of SEK 162 million ($15.5 million).
Fortunately, Sweden is the second most energy efficient country in Europe, and one of the world's biggest consumers of hydropower.
Governments, universities, and business partnerships are working together to push for significant investment and infrastructure across the country.
"It is likely that for a number of years to come, we will need a mix of aircraft that run on electricity, less environmentally harmful e-jet fuel and hydrogen. But every aircraft that can be powered by hydrogen from renewable energy reduces carbon dioxide emissions," said Grönstedt.
The full findings of the study were published in the journal Applied Thermal Engineering.
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