The Green Airport Conundrum
Sustainable airport design is a lot more than meets the eye.
A version of this story first appeared in Business Traveler.
A serene Southern California space greets you when you step into the new Terminal 1 by Gensler at San Diego International Airport. A glass curtain wall surrounding the lobby lets in natural light. The terrazzo floor subtly guides travelers through check-in and security. And strategically placed skylights bring light down to the ticket counters and bag drop at the back of the spacious hall.
What the space is not is hot, even as the south-facing glass wall bakes in the Southern California sun. That’s by design, said Terence Young, an aviation leader and principal at Gensler, who worked on the project.
The glass itself is cupped and fritted, two treatments that allow light into a space while reducing heat and glare. The large, cantilevered canopy atop the three-story facade shades the lobby from the sun. “It lets in the light, but the big overhang creates enough shadow so that at the ticket counters and TSA positions, you’re blocking this solar orb,” he said.
That combination of light but less heat and glare is something of a triple win for San Diego as the airport works to reduce its environmental footprint. The entire terminal, including the facade, will use roughly 20% less energy than comparable structures while also delivering a great experience for travelers.
Environmentally friendly design is an all-encompassing rethink of the airport terminal. It begins with low-hanging fruit like power-sipping LED lights and extends to everything from energy sources to building materials.
I struggled when I received this commission. The first answer I received to my query on what aspects of green design travelers see was “not much.” Many spoke of lighting. To be honest, much of the work to reduce an airport’s carbon footprint goes on behind the veil from conservation of both energy and water to electrification.
Even the greenest airport does not address the emissions elephant in the room: flying. Airports account for just 2-3% of total aviation emissions, according to the trade group the Airports Council International - North America (ACI-NA). If aviation is serious about its net-zero goals, airports need not be at the top of the list.
An airport can still do a lot to minimize its footprint. Come take a walk with me.
Departures
Hop off the MAX train at Portland International Airport (PDX) and make your way upstairs to departures. The terminal core by ZGF Architects that opened in 2024 is the quintessential image of a “green” airport.
Wood beams in concave curvaceous forms line the roof. Dark green carpet defines the check-in desks. And, after bag drop, actual trees growing in the center of the terminal form something of a demarcation line between the ticketing area and and the rest of the grand hall. This is about as close as you get to a walk through a Pacific Northwest forest while still in an airport.
“If we can make our indoor environments more like our outdoor environments, then we can attain those physiological and psychological benefits,” said Jacob Dunn, a principal at ZGF who worked on the project, on the terminal’s biophilic design.
The thing about biophilic elements is they are not necessarily green in practice. Yes, in a literal sense they are green but, as Dunn explained to me, indoor plantings and other flora often require additional lighting and watering systems compared to a traditionally-designed space.
Conversely, mass-timber buildings are widely acknowledged to have lower carbon footprints than ones built of steel, glass and concrete. It helps that the trees harvested to make PDX’s wood-beamed roof were all sourced within 300 miles of the airport.
The trade-offs are very real.
“To have these heroic landscapes inside … it’s worth it from a carbon and energy standpoint,” said Dunn. Not to mention a customer-pleasing one as well.
Airside
Go through security and make your way to the gate. That walk may include a stop at the shops in the airside core at Pittsburgh International Airport where daylight streams down on you through one of architect Tasso Katselas’ skylights or a brief respite beyond the glass on one of Denver International Airport’s three airside terraces.
Those skylights and picture windows are elements of green building. The sunlight they allow into a terminal, often in a controlled manner — ever notice glass that seemingly darkens when the sun shines in? — helps meet modern airports’ dual pursuits of transparency and environmental stewardship. A naturally lit terminal needs fewer lights and can reduce heating and cooling needs as well.
Windows, however, are only a small piece of the airport energy puzzle.
“There’s a lot that’s behind the wall,” said Christina Cassotis who leads the Pittsburgh airport. A 3-megawatt solar farm opened on airport property in 2021 with another 4.7-megawatts now under construction. When complete, Cassotis said the array will meet most of the energy needs for the airport’s buildings.
Electricity for everything from lighting to HVAC systems is responsible for roughly 80% of airport carbon emissions, said Melinda Pagliarello, the managing director of environmental affairs at ACI-NA. Reducing those emissions is often less about physical design decisions and more about technology choices — say forced air versus radiant heating — and energy sources.
Take the Monterey Airport in California. A new HOK-designed terminal is under construction will be “energy net zero” when it opens in 2027. That net-zero claim is less about the physical design itself — renderings show a pleasant low-slung building with a strong sense of indoor-outdoor connection — and more about the on-airport solar array that opened in 2017.
Airports from Berlin to Hobby in Houston and the soon-to-open Western Sydney in Australia are all using solar installations to cut emissions.
Not every airport turns an eye skyward to cut emissions. Seattle-Tacoma International Airport sources renewable natural gas — think methane from municipal waste — to power its central heating and air conditioning plant, said Leslie Stanton, senior manager of environmental programs for the airport. That said, even Sea-Tac is installing some solar; the under-construction Concourse C expansion will feature a rooftop array.
While few of these efforts, from solar arrays to renewable natural gas, are visible to travelers they do make significant strides toward reducing an airport’s Scope 1, or direct, emissions.
“It’s about taking care of people,” Cassotis said of Pittsburgh’s resiliency efforts.
Arrival
When I spoke with Kirsten Ritchie, a principal at Gensler, about the green aspects of the Harvey Milk Terminal 1 at San Francisco International Airport (SFO), our conversation almost immediately went to arrivals. Not because Gensler and its partners debuted an innovative take on basement design but because of the luggage sorting system itself.
“Let me tell you, baggage handling takes a lot of energy,” she said.
Think about it: the traditional luggage system is made up of miles and miles of near continuously running conveyor belts connecting ticket counters to planes and back to the carousels. The containerized system Gensler and its partners installed for SFO cut energy use in half compared to the system it replaced, Ritchie said. Bonus: the number of lost bags dropped too.
These improvements, like energy sources or HVAC systems, take place behind the veil of the airport wall. Travelers never see how their bag gets to them — though maybe they would enjoy some airport version of the open kitchen with viewing portals into the maze of conveyors that underlie terminals — or how the lights turn on.
That is the conundrum faced by architects designing green airports. So many of the things that make an airport actually green are invisible, or at least immaterial to the traveler experience. Those that are visible tend to be the sum result of all those behind-the-scenes decisions that come together into a coherent, hopefully wonderful, whole.
“There is a climate crisis and we need to be part of the solution,” as Sea-Tac’s Stanton put it.
