Case-study evaluation of a combined noise barrier and solar panel in an urban area

The LIFE + project NOISUN, concluded in February 2016, had as main objective to demonstrate an innovative noise barrier that produces solar energy for distribution to local district heating systems. Specially adapted solar collectors were installed at a major transport thoroughfare for both road (the E20 motorway) and railway traffic in the Swedish municipality of Lerum, and the effect of the intervention was evaluated in several ways. In the beginning of the project, calculations of expected noise mitigation were performed. Before and after the noise barrier was erected two actions were performed: Questionnaires were sent out to concerned households, and sound level measurements were performed in combination with recordings of noise events. The insertion loss of the noise barrier showed to be very close to the estimations. The noise reduction was most pronounced for loud train pass-bys but not as much for road traffic noise from the E20 motorway (also, contributions from other streets made the room for road traffic noise improvement smaller). The questionnaire results are presented and discussed in relation to the measurement results. The analysis shows a clear improvement of the perceived noise situation, but also points to some of the problems inherent in field projects analyses.