Run on renewables

27 July 2020

Buses are vital in a smoothly run airport, ferrying passengers and employees alike. Unfortunately, most models chug along on diesel or petrol – but a new law for hubs on the US west coast may change that. Andrea Valentino chats with Michael Christensen, deputy executive director of operations and maintenance at Los Angeles World Airports, as well as Seth Morgan, Erin Cooke and Nupur Sinha of San Francisco International, to learn why California is taking the lead in bus electrification.

There was a time when buses had almost no place in airports. Before checkpoints and terrorist risks made boarding infinitely more complicated, passengers could poke at the dregs of their pre-flight cocktails and amble directly to the aircraft, or even have their chauffeur drop them off by the cockpit. Even if you’re not an expert in airport history, you can probably conjure a similar image – perhaps Neville Chamberlain flapping his white piece of paper on the runway, or Pope John Paul II kissing the tarmac as he landed in Dublin four decades later.

These days, of course, such scenes feel irreconcilably antique. As airports have grown and their security has tightened, passengers are now shepherded carefully down gangways or herded on to buses and driven from their gate. Indeed, according to one recent study, the international popularity of airport buses is expected to grow by 10% every year between 2019 and 2025. That broader trend is shadowed at particular airports too, with bosses everywhere from Munich to Gran Canaria investing in new buses over the past few years.

Not that this growth is free of challenges. With more buses comes increased pollution – hardly ideal in an industry already battling to get its emissions down. Look to the west, however, and a solution might be at hand. Working with local legislators, airports in California are leading the way when it comes to making their buses not only sustainable, but – crucially – efficient to run. Aside from making life better for passengers, these successes point towards the future of their industry at large – one where airports are run with the planet in mind.

Best of the west

California has long been one of the most environmentally progressive places on earth. As far back as 2006, Governor Arnold Schwarzenegger signed the Global Warming Solutions Act into law, heralding the first cap on greenhouse gas emissions anywhere in the US. By the middle of the next decade, more legislation had committed the Golden State to a range of ambitious environmental targets, from banning coal to sourcing half its electric power from renewable sources by 2030.

It is perhaps unsurprising, therefore, that California has also taken such a robust stance against that perennial bogeyman of eco-warriors everywhere: airports. In 2014, for example, authorities ordered 31 local airports to improve testing of ground water for dangerous chemicals. More recently, the state attorney general sued San Bernardino International for supposedly approving an expansion without commissioning a sufficiently thorough review of its predicted environmental impact. Even airport buses are coming under fire. Passed by the California Air Resources Board last June, the Zero-Emission Airport Shuttle Regulation obliges state airports to swap all their models with environmentally friendly alternatives by 2035 at the latest.

But talk to the airports themselves and – whatever their other challenges – it quickly becomes clear that they were transitioning to electrification well before that decision last year. “We have been planning and implementing electrification for a long time prior to the June 2019 ruling by California regulators,” says Seth Morgan, a senior transport manager at San Francisco International Airport (SFO). Among other things, Morgan notes that his airport had already purchased six zero-emission battery-powered buses. Michael Christensen, deputy executive director of operations and maintenance at Los Angeles World Airports (LAWA) tells a similar tale, explaining that his team was working to procure electric buses as early as 2017.

This activity can be understood in a couple of ways. As airports become larger, transit buses grow in importance too. At San Francisco, for instance, buses are now roped into a number of different roles, from shuttling passengers and staff from car parks, to herding travellers to their aircraft at remote hardstands. In recent years, airport buses have even been requisitioned when the trains connecting different terminals break down. Officials in Los Angeles make the same point. Buses at Los Angeles International (LAX) alone (LAWA encompasses both LAX and the smaller Van Nuys Airport) transported 2.4 million passengers in 2017 – totting up to a mammoth 54,000 trips.

Yet if California’s airports increasingly rely on their buses, traditional models also come with serious downsides. That begins with the environmental costs. According to a study by the Union of Concerned Scientists, diesel buses in the state emitted 70% more greenhouse gases than electric substitutes. This gap is reflected in the US at large, where buses running on diesel and petrol can emit anything from one and a half to eight times as many harmful emissions as their battery powered cousins. And, when you consider that only 0.5% of all transit buses in the US are currently electric, it becomes clear that airports have plenty of room to adapt.

Aside from their planet-busting fumes, older airport shuttles suffer from other drawbacks. Between their grumbling engines and uncomfortable ride, they can often make the trip from the gate to the aircraft even less relaxing for anxious flyers. Combined with a lack of luggage space and hard plastic seats, it’s unsurprising that airports are so keen for change.

Start coaching

Like everything else, the Covid-19 emergency has ravaged airports – and therefore airport buses. With domestic departures in California down roughly 65% since early March, and big airports like LAX cancelling as many as 75% of such flights, the state and its aviation industry are suffering. Without flights or passengers, meanwhile, the grand plans airports have for buses have also been impacted. As Seth Morgan laconically puts it, “Covid-19 has definitely slowed down” San Francisco’s roll-out of its new bus fleet.

Even so, you only have to talk with staff at Californian airports for a few minutes to realise how desperate they are to get back to work – not least when it comes to transit. As with California generally, the environment is a big source of excitement. “SFO has been tracking our emissions since the 1990s, and we view reducing emissions as a key part of our responsibility to the local and global community,” says Morgan, a point echoed by his colleague Erin Cooke. “Transportation decarbonisation is a key priority of SFO’s carbon-neutral goal,” notes Cooke, the sustainability director at SFO.

Though Morgan, Cooke and the rest of the San Francisco team are yet to compile figures on how much their new electric buses will cut emissions, their counterparts in Los Angeles certainly give reasons for optimism. All told, officials at LAWA believe that switching 20 diesel-operated buses to battery-electric buses will cut greenhouse gas emissions from 308t per year to zero. That is the equivalent of over 34,000gal of gasoline, or 66 conventional passenger vehicles. No wonder Christensen feels comfortable predicting that his new fleet will play a “substantial part” in achieving sustainability goals at LAWA.

Apart from these environmental advances, the new buses are transforming the customer experience. Aside from featuring spacious luggage storage racks and padded comfortable seats, the San Francisco fleet will be far quieter than before. More broadly, Morgan wonders whether sitting in an eco-friendly bus might give environmentally conscious passengers a morale boost. “I think the best benefit to passengers is knowing that the bus they are riding is helping reduce the environmental impact of their journey.” Perhaps – but what is more certain is the impact the new buses will have on airport accounts. Though the initial cost of electric buses is higher than internal combustion engine alternatives, they are ultimately two and a half times cheaper to run.

Of course, converting whole fleets of buses away from tried-and-tested diesel was never going to be simple. Morgan notes the airport had to make sure that his facility had enough capacity to power a batch of new electric chargers. Christensen agrees, highlighting how he and his team installed 11 similar chargers at LAWA.

And, Christensen continues, this technological wizardry has apparently paid off – the buses are running “flawlessly” and LAWA is rapidly becoming a “model for other airports committed to reducing their carbon footprint”.


Despite all this innovation, there is a sense that buses themselves might soon disappear as well. Though they are certainly cleaner than old-fashioned diesel models, electric buses still need to get power from somewhere – and that sometimes includes nasty sources. It makes sense, then, that airports are looking for ways to abandon buses altogether. The most obvious method involves getting passengers to aircraft on foot, via elevated gangways. “Our long term plan is to have enough gates to accommodate all passengers via jet bridges, because passenger experience and ease of travel are our key goals,” says Nupur Sinha, the planning and environmental affairs director at SFO.

At the same time, Sinha emphasises that buses and their future are part of a far broader strategy. “SFO built the first certified net-zero energy airport facility in the world,” she explains, “and is currently installing the most sustainable baggage-handling system in North America.” You can hear similarly comprehensive plans from Christensen too. Among other things, LAWA hopes to achieve carbon neutrality, use 100%-renewable electricity and stop the use of potable water for industrial uses by 2045.

These are certainly ambitious plans, but hardly unthinkable. If the story of airport buses tells us anything, it is that nothing ever stays still for long, and that even iconic scenes of smartly dressed men ambling towards a small propeller aircraft, umbrellas at their side and a few whisky glasses back at the airport bar, can quickly become outdated.

2.4 million

Passengers ferried by buses at LAX in 2017.


Buses that run on electric power in the US.
Eb Start


Barrels of gasoline predicted to be saved by LAWA by electrifying its bus fleet.

SFO’s new electric buses are more expensive to build than regular diesel ones, but are considerably cheaper to maintain.
Airport buses are gaining in popularity as well as demand, making the green conversion of their engines vital.

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