Bristol Airport has just announced the completion of a "ground-breaking" hydrogen refuelling trial which the transport hub says sets air travel on the next step for zero-emissions flights.

Led by easyJet and supported by several cross-industry partners, the trial was the first of its kind at a major UK airport. It featured the use of hydrogen to refuel and power ground support equipment: ensuring that the emissions from baggage tractors, which service easyJet passenger aircraft were emissions-free.

Tim Johnson, Director for Strategy, Policy and Communications at the Civil Aviation Authority, said: "Projects such as this are cornerstones of our commitment to support innovation and decarbonisation in the industry.

The trial results will become the basis of a White Paper for government policy, as well as allow for the creation of further safety guidance and regulatory standards, he added.

"We look forward to helping nurture this seed of the future greener aviation sector as it continues to grow."

David Morgan, Chief Operating Officer at easyJet, said: "It's without doubt hydrogen will be an important fuel of the future for short-haul aviation, as demonstrated by the rate of innovation we're seeing.

"While the technology is advancing at an exciting pace, as hydrogen isn't used in commercial aviation today, there is currently no regulatory guidance in place on how it can and should be used, so trials like this are very important in building the safety case and providing critical data and insight to inform the development of the industry's first regulatory framework. This will ensure regulation not only keeps pace with innovation, but importantly also supports the industry in meeting its decarbonisation targets by 2050."

Conducted as part of the airline's daily operations, the trial demonstrated that the gas can be safely and reliably used to refuel ground equipment in the busy, live airport environment.

The trial, dubbed Project Acorn, was in development for over a year and involved many other leading organisations from across aviation, engineering, logistics and academia. These include Cranfield Aerospace Solutions, Cranfield University, Connected Places Catapult (CPC), DHL Supply Chain, Fuel Cell Systems, the IAAPS research institute, Jacobs, Mulag and TCR.

The group intends to use the outputs of the trial to help develop industry best practice standards, provide guidance to airports, airlines, local authorities and regulators on required infrastructure changes, and support the development of a regulatory framework for hydrogen's use on an airfield - standards which, due to hydrogen's nascency in aviation, do not currently exist.

The data and insights gathered will also feed into research that groups like Hydrogen in Aviation are conducting to ensure UK infrastructure, regulatory and policy changes keep pace with the technological developments in carbon-emission free flying. Additionally, it supports the work and ambitions of other bodies such as Hydrogen South West (HSW) and the Hydrogen Innovation Initiative (HII), the latter having also co-funded the project.

Anthony Browne, Aviation Minister, said: "Project Acorn is a great example of the UK aviation sector pushing the boundaries of what's possible - using leading engineering to make decarbonisation a reality from the ground operation to the planes themselves.

"Innovative projects like this are crucial to achieving our target, set out in the Jet Zero Strategy of zero emission airport operations by 2040."

There is a compressed time window for the UK's aviation industry to develop the ground infrastructure, safety standards (including how to use, control and transport hydrogen) and operational procedures needed to make the sector's operations hydrogen-ready. Project Acorn is designed to be a first step on this journey, with limited trials of GSE equipment accomplishing a key objective of receiving clearance for airside refuelling from the Civil Aviation Authority - the regulator playing an active role in the trial as an independent reviewer of the safety case.

A spokesman for the trial said: "While hydrogen is a potential zero carbon emission fuel source for aviation and important developments have already been made across the industry, there remains significant regulatory, safety and certification challenges. More research and testing is therefore required to inform hydrogen infrastructure policy and safe handling in airport and airline operations to support future hydrogen adoption.