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Green advisor

Tomorrow’s airports are built on sustainable solutions

Shopping malls, yoga studios, squash courts – as the numbers of travellers rise, airports are competing to offer the most attractive pre-flight environments. However, the biggest challenge facing airports worldwide is to maximise their appeal, accessibility and efficiency while minimising environmental impact.

ÅF is managing a project to extend Oslo’s Gardermoen Airport. When complete in 2017, the extension will set a new international standard in environmentally adapted airports. 

Steep increase in passenger numbers

Last year 3.2 billion journeys worldwide were made by air. The rise in passenger numbers is driven by factors such as globalisation, increased competition from low-cost airlines and a burgeoning middle class. Air travel’s main impact on the climate is aircraft carbon dioxide emissions, but airport activities and road traffic to and from the airport also play a part. To create a sustainable airport requires a holistic approach that includes aspects such as climate-smart energy production and construction techniques, and sustainable transport options to and from the airport. It is also important to make sure there is sufficient on-site capacity, as a disproportionate amount of emissions is due to overcrowded terminals and skies.

Gardermoen’s environmental commitment 

One airport that has invested heavily in new technology and innovations to minimise environmental impact is Gardermoen outside Oslo.

Gardermoen is the hub for air travel in Norway. In 2014 the airport was Scandinavia’s second busiest with some 24 million passengers. Only Kastrup in Denmark is larger. To meet the rise in passenger numbers, work on extending Gardermoen began in 2009. The aim was to manage a throughflow of 28 million passengers with the possibility of extending the airport further if necessary. At the same time sights were set high in terms of climate impact and the environment.

The airport must slash its energy use by 50 percent and at least 70 percent of passengers must be able to travel to the airport by public transport.To meet its capacity target and cater for up to six million more passengers, Gardermoen needs a new taxi runway, a new 117,000 square-metre terminal, a 300-metre long pier with 17 gates and 34 check-in desks, and an adjacent arrivals and departures hall. The estimated cost of this ambitious project is 1.5 billion Euros.

Important regional political issue

A bigger, better Gardermoen is crucial to provide much needed future capacity and to strengthen regional development in Oslo and in Norway as a whole. That is the firmly held belief of Magnhild Meltveit Kleppa, Norway’s Minister for Transport at the time the decision was made in 2010 to extend Gardermoen.

“Had we not decided to expand the facilities, Gardermoen would soon have been forced to turn away flights and passengers,” she says. “Norway’s geographical location and settlement pattern mean that trade and industry as well as private individuals are all highly dependent on air travel. Good conditions for air traffic are an important political issue – but for our future well-being, it’s essential that we achieve these through long-term sustainable solutions.”

ÅF leads the expansion project

Work to create a new, climate-smart Gardermoen has been led since the start in 2009 by ÅF Advansia. Norway’s largest airport owner, Avinor, has commissioned ÅF to oversee all phases of the project, from design, construction and purchasing to installations, testing, documentation, training, start-up and operational hand-over. “Having all-round responsibility for the project gives us a greater opportunity to influence ambition levels and solutions for sustainability. Projects like this enable us to optimise the collective competence and experience we have at ÅF,” says Per Børresen, who is heading the project management work at Gardermoen.

Unique construction solution

One of the key aims of the project is to make Gardermoen an international role model among environmentally adapted airports. The environmental demands are daunting, both during construction and throughout the operational phase. For example, some 87,000 square metres of the extension need to meet passive building standards. Passive buildings are super-insulated to minimise energy loss, and with the new addition Gardermoen will be the first airport in the world to build to this high standard.

“This airport extension will be unique. Gardermoen has as many passengers as Stockholm Arlanda Airport, but fewer square metres. It’s a highly compact design that makes optimum use of every inch of space. That’s important from a sustainability perspective,” Børresen explains.

Groundwater must be conserved

Gardermoen lies on top of one of Norway’s largest sources of groundwater, which is protected by law and various other statutes from any pollution from the airport. Preventing the chemicals used to remove snow, ice and slush at Gardermoen from infiltrating the groundwater was an important factor that the ÅF team needed to bear in mind throughout the project. “It’s important to maintain the right water balance in the ground below Gardermoen. That is a key requirement for the airport’s very existence. One of the targets set for the project is to have zero emissions to groundwater,” Børresen says.

When completed, Gardermoen will boast a number of energy solutions that are unique among the world’s airports. Snow saved from the winter will be used to cool the terminals on hot summer days, and purified wastewater will be used as a source of heat. The biggest environmental gains from the new energy solutions will be seen in a dramatic reduction of energy use. The target is to save 9GWh a year, a saving corresponding to the energy used by 450 private homes.

Snow keeps Gardermoen cool

In winter huge quantities of snow are cleared from Gardermoen’s runways and elsewhere on the site. ÅF has developed a unique solution for turning this snow into district cooling.

The basic idea is simple. Clean snow is separated from polluted snow, collected and stored in a 50,000 cubic-metre trough-shaped stockpile at the airport. When full, the stock tank is covered with an insulating layer of wood chips, helping to preserve the snow and ice well into the summer. The meltwater is then channelled through a filter and into a network of underground pipes to a heat exchanger, where it cools the air in the buildings’ ventilation system. When the air has been cooled, the water (now lukewarm) is pumped back to the stockpile to be cooled down once more. Any excess water is allowed to drain into the ground to preserve the groundwater level.

Technology to use snow for district cooling is installed in only a handful of facilities around the world, for example in Japan and in Sweden’s Sundsvall Hospital. But the idea is not new. In the nineteenth and twentieth centuries ice from lakes was used to keep food cold. Blocks of ice were sawn up in winter and covered in sawdust so they would last until summer.

From wastewater to warm air

On average every EU citizen uses 160 litres of water a day: 40 percent of this is hot water. In other words, a lot of hot water goes into the sewerage system when it could be used to produce energy.

Gardermoen re-uses purified water from the nearby municipal water treatment plant at Ullensaker. Once the water has been purified, the heat it contains is transferred using a heat exchanger and pumped to the district heating system, where it is mixed with hot water from existing groundwater wells. The energy is then extracted from the water and used to heat the airport on the many cold days of the year that are characteristic for Oslo’s northern climate.  

World-class climate solutions

As a result of Gardermoen’s unique energy solutions and the developer’s systematic focus on the environment and the climate, the expansion project has attracted huge international interest. The airport has been awarded numerous environmental certificates, including a rating of “Excellent” in accordance with BREEAM Bespoke criteria. BREEAM is one of Europe’s foremost environmental certification systems for assessing and rating the overall environmental impact of buildings.

Such international recognition is sound proof that Gardermoen has come a long way in its ambition to become a world-leader in developing airports that have the smallest possible impact on the climate.