The site Lobau is not only the office center of Shell Austria GmbH, but also there is located a lubricant factory and a fuel depot. To supply the thermal energy, two steam boilers with a heat capacity of 6 MW each are available that supply heat to the consumers via a steam system over an elevated pipe route. Heavy heating oil is used as fuel. The building is heated by a warm water system that obtains its energy from the steam system. Further, a neighboring company is also supplied with steam. The steam system was built in 1972, in succession few investments for maintenance were made and a renewal was considered, therefore it has been decided to execute an energy demand evaluation as support for the coordination of the new facility. 2009 was set as base year. Looking at the documentation of the steam recorder at that stage there is an annual output of 23513 tons of steam with a temperature of 240 °C and pressure of 12.5 bar. Following consumers are supplied: jet tank facility, base tanks, VIS-50 facility, oil mixing plant, office and workshop area, lab and changing rooms, stocks, filter plant, P2P (neighboring company). The base tanks were identified as the biggest consumers. Moreover, it appeared that a lot of energy gets lost on the one hand by the distribution due to above ground installed pipes, and on the other due to defect steam traps.