Hubs across the globe are striving to reduce their carbon footprint – as well as their running costs – by installing wind turbines and solar power systems and reducing emissions.

Air traffic makes up just 2% of global carbon dioxide emissions, according to the United Nations Intergovernmental Panel on Climate Change, but with airport activities accounting for 5% of this, airports across the globe are doing more to reduce their carbon footprint.     

Boston’s Logan Airport, for example, has been using 20 roof-mounted wind turbines on the airport’s administration centre to generate electricity for the building since 2008. This amounts to roughly 2% of the office complex's monthly power consumption. Copenhagen’s Kastrup Airport  began installing energy-efficient heat exchangers in 2010 to manage terminal temperatures, and Denver International Airport has access to an eight megawatt solar array system, one of the largest airport systems in the US, which  has been providing 6% of the airport's electricity since July 2011.

“Climate change is an issue that is affecting everyone, and airports have their own part to play in finding a solution,” said Gary Hodgetts, director of operations at London City Airport.

However, going green is not just a matter of corporate social responsibility; it is also something that will reduce airport running costs. “This can lead to increases in air service as airlines find lower costs attractive,” said David Magana, a senior manager at Dallas Fort Worth Airport. “And passengers do notice when airports attract more air service.”

To date, 64 European airports have signed up to the Airport Carbon Accreditation Scheme, a voluntary initiative launched in 2009 that aims to reduce emissions from ground transport, boost the use of renewable energy and increase the energy efficiency of airport terminals. The scheme – which accounts for  more than half the region’s air passenger traffic (780 million passengers each year) –  includes some of Europe's busiest hubs, including Frankfurt, London’s Heathrow and Paris’ Charles de Gaulle. The scheme extended its remit last year to cover Asia and the Middle East, where six airports have signed up, including Mumbai, Abu Dhabi and Singapore’s Changi airports.

And the scheme is working. Helsinki Airport, for example, has cut its carbon dioxide emissions by nearly 2,500 tonnes compared to 2011, by making heating, ventilation and lighting more energy-efficient, as well as using electrically-operated vehicles. “This corresponds to an emissions reduction of 0.4kg per passenger, or the amount of fuel transported by 23 container trucks,” said Heini Noronen-Juhola, vice president at Helsinki Airport.

Going green at an airport is not always easy. For instance, if renewable energy sources such as solar panels and wind turbines are installed on-site, they have to be clear of runways and air traffic control towers. But it is clear that airports can reap the rewards over time. Athens, Greece has one of the largest airport solar power plants in the world, supplying 8.05 megawatts of electricity to the terminals, with this source of renewable energy accounting for 10% of the airport community’s needs, from lighting to heating. This has resulted in an estimated cost savings of one million euros over the last six years.

The leading challenge with solar power, however, remains the storage of energy during the day for use at the airport at night. A lot of progress is now being made with manufacturers testing new battery technologies, but this is not yet in use commercially.

However, even if the airports themselves are trying to reduce their emissions, it is difficult to control all the concessions and sub-contractors that work within big airports. Copenhagen alone has 500 companies operating on-site and roughly 23,000 employees.

“We estimate that around 94% of the emissions per passenger stem from sources outside our direct control,” said Inger Seeberg Sturm, head of environmental affairs, at the airport.