Three-dimensional hydrodynamic modelling in a bay of the Lake Mälaren to assess environmental impacts from a cooling and heating power plant production

Pierre-Louis Ligier, Non Okumura
2020 Zenodo  
The power production company Norrenergi owns a power plant in Solna, Stockholm county, Sweden, to produce heating or cooling energy by exploiting intake water's temperature. In its current configuration, the power plant is connected to the network of the Bromma sewage treatment plant, located in the northern part of Stockholm and uses this water for production. The planned commissioning of a new sewage treatment plant in Henriksdal in the southern part of the city, thought to replace the Bromma
more » ... replace the Bromma sewage treatment plant, will lead the current sewage network used by Norrenergi's power plant to be decommissioned. In order to maintain water supply for its power plant, Norrenergi is now seeking environmental permit to use water from the Bällstaviken bay in Solna where the old intake and outlet structures exist. This article presents the hydrodynamical modelling performed as part of the environmental permit application. The work has focused on describing the thermal dispersion conditions for an extreme energy demand in the summer (cooling production), where the released water temperature is increased between 5.5 and 10.0 °C during a daily cycle. Hydrodynamic modelling has been performed with the software TELEMAC-3D version 7.3. The first part of the modelling work has been to perform flow measurements in order to calibrate the model with respect to currents. Some preliminary dispersion tests showed that in their current configuration, the current intake and outlet structures, both located in the Bällstaviken bay, do not offer optimal production capacity due to a very high risk for a temperature shortcut. To mitigate this risk, a new location for the inlet has been investigated. A location in the adjacent Ulvsundasjön bay has been chosen which offers the possibility to take water from a greater depth with a cooler temperature especially during summer months, making it possible to reduce the relative< [...]
doi:10.5281/zenodo.3611558 fatcat:vzieizxd7bdk5pyess6kn743j4