Beyond the net zero terminal: the infrastructure that decarbonises aviation

Airports have made visible progress in reducing the environmental impact of their terminals. Yet most aviation emissions occur beyond the building itself. The bigger opportunity is to create the infrastructure that enables airlines, passengers and operators to cut their emissions.

Over the past decade, energy efficient buildings, low carbon materials, on-site renewables and smarter controls have become the main measures of airport sustainability. That progress matters: efficient terminals cost less to run, are more resilient and demonstrate environmental commitment. 

However, there is a growing risk that the industry is focusing on the wrong metric.

Most aviation related emissions don’t come from airport buildings. Aircraft operations, auxiliary power unit (APU) use, passenger and employee journeys, ground handling, fuel supply chains and construction all typically sit within Scope 3 emissions. Analysis by Roland Berger estimates that Scope 3 accounts for around 85% to 95% of the addressable emissions within an airport's sphere of influence. At airports that have already reduced direct emissions significantly, Scopes 1 and 2 together may be less than 5% of the total.  

The precise proportion varies with accounting boundaries and traffic profiles, but the lesson holds. If most emissions occur beyond the terminal, then sustainability cannot be measured solely by the carbon performance of the terminal building. The next phase must focus on the infrastructure that enables aviation itself to decarbonise.

From a low energy building to a low carbon aviation system

The industry's leading carbon frameworks already reflect this shift. At Level 5, Airport Carbon Accreditation requires airports to maintain at least a 90% reduction in Scopes 1 and 2 emissions, apply credible removals to residual emissions and commit to net zero Scope 3 by 2050 or earlier. That means engaging airlines, suppliers and service providers on the emissions the airport can influence.

Airports don’t control aircraft technology, passenger travel choices or airline procedures. They do control the physical environment in which many of those decisions are made. So, the question changes from "How do we reduce the carbon footprint of our buildings?" to "How do we create the infrastructure that allows airlines, passengers and operators to reduce theirs?"

That shift moves sustainability discussions away from individual buildings and towards energy systems, fuel infrastructure, utility networks, electrical capacity, resilience strategies and long-term flexibility. Sustainability becomes a systems level challenge rather than a building performance exercise.

Beyond SAF: designing for a changing aviation energy system

Much of today’s discussion on decarbonisation of air travel centres on Sustainable Aviation Fuel (SAF).

IATA estimates that SAF could contribute up to 65% of the emissions reductions required for aviation to achieve net zero by 2050. Existing SAF pathways typically cut lifecycle emissions by around 80% compared with conventional jet fuel, though this varies by feedstock and production route. One of SAF's greatest strengths is that works with existing aircraft and airport fuel infrastructure, so it can deliver reductions now.  

Yet SAF is unlikely to be the final answer. Hydrogen, battery-electric and hybrid-electric aircraft are all in development and Airport Compatibility of Alternative Aviation Fuels Task Force (ACAAF-TF) expects conventional and alternative propulsion aircraft to operate side by side at both existing and new airports. Hydrogen is the biggest step change. Unlike SAF, it isn’t a drop-in fuel and would require new aircraft, new operating procedures, new skills and new airport infrastructure. Airbus points to whole new supply chains for production, liquefaction, storage, transport and distribution, and more than 220 airports have joined its Hydrogen Hub initiatives. Hybrid-electric propulsion raises different questions again, and its airport implications are still unclear.  

This leaves airport planners with dilemma. An airport designed today may remain operational until the end of the century, yet many of the technologies that could dominate aviation in 30 or 40 years do not exist commercially at scale. The aim cannot be to predict the winning technology. It has to be flexibility.

In practice, that means safeguarding land, utility corridors, technical space and electrical capacity, and avoiding masterplan decisions that make future adaptation prohibitively difficult or expensive. Often the most valuable investment today isn’t a physical asset at all, but the option to accommodate future technologies that remain undefined.

Electrification is not one project

Electrification is often treated as a set of separate projects: passenger and staff vehicles charging, ground support equipment, airside vehicles and aircraft taxiing. In reality, all of these ultimately become part of the same energy strategy.

IATA reports that electric ground support equipment can cut CO₂ per turnaround by 35-52%, while also reducing local air pollution and noise. Meanwhile, engine-off taxiing and other airside technologies have shown they can reduce fuel burn during ground movements. At the stand, Fixed Electrical Ground Power (FEGP) and Pre-Conditioned Air (PCA) let parked aircraft switch off their APUs, cutting fuel consumption, noise and emissions.  

Viewed one at a time, each initiative looks manageable. Viewed together, they reshape the airport's whole utility strategy. That's why planners need to look at cumulative demand across the estate, not individual business cases.

Understanding that demand is where many projects get caught out. A hot summer afternoon with multiple wide body departures can create a very different demand profile from an average operating day. Similarly, winter heating requirements may influence PCA demand significantly. Simple diversity factors applied uniformly across a terminal won’t capture this. Electrical infrastructure should be sized using realistic assumptions about schedules, stand allocation, turnaround durations and climate conditions. The question is no longer the connected load, but the operational load.  

The airport as an energy platform

Taken together these trends turn airports from transportation infrastructure into major energy platforms. Passenger charging networks, electric ground support equipment, PCA systems, future propulsion, data infrastructure, renewables and energy storage will all compete for capacity within the same ecosystem. An industry working paper presented to the 42nd Assembly of ICAO identified growing airport electricity demand, grid constraints, renewable energy availability and infrastructure investment as key challenges for the sector. The paper notes that major airports may experience substantial increases in electricity demand as electrification accelerates across multiple systems.

Sizing utilities around today’s known loads is no longer enough. Future airport energy strategies should consider:

• Long-term scenarios rather than fixed forecasts.
• Future propulsion technologies and their energy needs.
• Utility flexibility and spare capacity.
• Storage, demand management and on-site renewables.
• The potential interaction between currently unrelated systems.

The most successful airports will not simply consume energy more efficiently. They will become sophisticated managers of energy.

Decarbonisation cannot come at the expense of resilience

Sustainability and resilience are often discussed separately, but at an airport they are inseparable. Airports are critical infrastructure, and passengers, airlines, operators and regulators expect them to keep running whatever happens elsewhere.  

Every new electrification initiative raises the same questions. What happens during a grid failure? Which systems must remain operational and how should loads be prioritised? What level of redundancy is required and how can infrastructure be maintained without disrupting airport operations? These are not arguments against decarbonisation. They are reasons to engineer it correctly.

As airports electrify, their dependence on electrical infrastructure grows, and resilience becomes more important rather than less. A low carbon airport that cannot maintain operations is not sustainable. Equally, a highly resilient airport that cannot adapt to future energy requirements is not future ready. The challenge is delivering both at once while balancing maintainability, flexibility and cost.

A better measure of airport sustainability

Terminal energy performance, operational carbon and building certification all remain important.

But none of them fully capture the role airports will play in aviation's transition. An airport may achieve exemplary building performance metrics while lacking the electrical capacity, fuel infrastructure or flexibility future aircraft will need. Another may invest heavily in infrastructure whose emissions savings show up in airlines’ inventories rather than its own.

So, airports should be judged not only on the emissions they produce, but also on the emissions they enable others to avoid. The most sustainable airport is not necessarily the one with the lowest energy terminal. It’s the one that makes lower emission aircraft operations, cleaner surface access journeys, reduced APU use and new fuels possible.

Few organisations sit at the intersection of as many stakeholders as an airport: airlines, passengers, transport providers, regulators, energy companies, service operators and infrastructure owners all meet there. That gives airport leaders real influence over how aviation's transition unfolds. The question to them is no longer how to reduce the airport’s own footprint, but how to design an airport that can support aviation’s decarbonisation for the next 50 years.  

The airports that answer it well will be best positioned to accommodate future fuels, future aircraft and future operating models. They will not simply be low carbon airports. They will be the airports that help make low carbon aviation possible.

To find out how Cundall can help you plan airport energy infrastructure that's ready for future fuels and aircraft, get in touch.