The aquifer – the world’s largest energy storage unit

The world’s largest energy storage unit − the aquifer that supplies space cooling and heating for Stockholm Arlanda Airport − has been in service since the summer of 2009.

Aquifer-based heating and cooling system in operation

Stockholm Arlanda’s aquifer has been in service since the summer of 2009 – from now on, all cooling of airport buildings, including the terminals, will come from the aquifer.

During the summer, the aquifer supplies cooling to Stockholm Arlanda’s buildings while at the same time storing heat. In the winter, this stored heat will be used in the ground heating system at the airport’s aircraft parking stands and to pre-heat ventilation air in buildings.

Cheaper, more environmentally friendly energy production

Arlanda consumes as much energy as a city of 25,000 people. Areas as large as one hundred European football pitches need to be cooled in summer and warmed in winter. The aquifer, which is located in the nearby boulder ridge known as Brunkebergsåsen, will help make energy production at Stockholm Arlanda both cheaper and more environmentally friendly. The aquifer will be used to supply cooling and heating to the airport.

How the aquifer works

The aquifer can be described as a huge groundwater reservoir that functions like a thermos. Water that is pumped out of the aquifer delivers cooling to the airport in the summer and heating in the winter. Cold water is pumped out of the aquifer in the summer to be used in the airport’s district cooling network. Warmed-up water then flows back and is pumped underground and stored until winter when it is needed to melt the snow in aircraft parking stands and pre-warm the ventilation air in buildings. 

Reducing electricity and heating consumption by 19 gigawatts

The aquifer will reduce the airport’s annual electricity consumption by 4 GWh and its district heating  consumption by around 15 GWh, for a total of 19 GWh − equivalent to the energy consumed by 2,000 single-family homes.

Dual environmental effect

Since 2005, Swedavia, formerly LFV, has been using only “green” electricity and since 2006 only district heating based on biofuel at Stockholm Arlanda. The aquifer will make it possible for this volume of green electricity and biofuel-based district heating to become available for others to buy