The greatest demand for energy at DESY takes the form of electrical power. This is used to run its accelerators. The accelerators currently in operation are LINAC, DESY II, FLASH I+II and PETRA III. In recent years, the consumption of electrical power has been around 150 gigawatt-hours (GWh); if the consumption of XFEL is included, it amounts to about 210 GWh.

DESY also operates an organisational load management system. This allows smoothing out large power peaks in electricity consumption.

The heat required on the DESY site for heating and air conditioning is provided by district heating, among others. For this purpose, DESY has its own local heating network which connects the campus. Heat is fed into this network from Hamburg’s district heating network.

In addition to the district heating, heat is recovered from the cryogenics plant, i.e. the low-temperature refrigeration plant.

This waste heat accounts for approximately 50% of total demand. A brief description is available at energy efficiency projects (renew link when website goes live).

Alongside the local heating network, DESY also operates a cooling network. This makes it possible to supply cold water from a total of three cooling centres to a number of different consumers (computer centre, accelerators, laboratory buildings, etc.). The advantage of this is that not every consumer needs a chiller, and large systems can be operated much more efficiently. The three cooling centres are connected via the cooling network, hence the term “cooling ring”. This cooling ring has been fully operational since the beginning of 2016.

During the cold season free cooling can be used to reduce energy consumption. This is already being implemented in the case of the FLASH II accelerator. Here, the accelerator’s 20°C cooling circuits switch to free cooling once outside temperatures drop below 15°C. The cooling water is cooled down in cooling towers, with the help of ambient air and fans. This only consumes small amounts of electrical power compared with the chillers that otherwise cool the water.

Water is used for various purposes at DESY. On the one hand, it is used to operate sanitary facilities and kitchens and, on the other hand, to cool the accelerators. The water that DESY needs in the form of drinking water is purchased from the municipal supplier. Most of the water required for cooling its accelerators is obtained by DESY itself, from five wells located around the DESY site. The water from the wells is deionised in our own water treatment plant and used as deionised (fully demineralised) water. In 2022, for example, 15% of DESY’s water needs were procured from the supplier, while 85% came from its own wells.