Great spread

District cooling has been widely implemented in the Swedish capital. In fact, fully seven million square metres of commercial area in Stockholm is connected to the district cooling network. The city’s district cooling set-up comprises multiple installations with varying capacity – from 3 MW to 228 MW, where the biggest installation is the one that supplies the central areas of Stockholm It may seem something of a paradox that large-scale district cooling got off to a flying start in northern Europe, given that the need for cooling is more typically associated with the south of Europe. District cooling was originally introduced in Stockholm in 1994, and the market reacted positively to this innovation, which was driven in part by a political decision to phase out CFC and HCFC coolants because these substances were causing major damage to the ozone layer.

Demand greater than expected

The energy company Fortum is the biggest district cooling player in Stockholm. This company alone is responsible for half the total district cooling supplies in Sweden. Fortum quickly spotted that the need for cooling applied for a greater part of the year than expected. The reason for this is that demand is linked not only to hot weather, but also to the need to cool electronic equipment – not forgetting requirements linked to refrigerators and freezers, as well as commercial and industrial installations. District heating provides maximum savings at electricity supply facilities during peak load periods in the summer. However, the Stockholm example demonstrates that district cooling also provides significant savings on electricity bills for installations that experience peak load in the winter.

Fortum currently supplies around 500 GWh of district cooling per year. Were a corresponding volume to be generated in conventional ways, it would demand five times as much electricity. In other words, district cooling reduces the demand for electricity for cooling by 80%.