Preliminary study of noise propagation behaviour at the Nesjavellir geothermal field, SW-Iceland

Abstract

A study of noise propagation was carried out at well sites NV-16, NV-21, NV-22 of the Nesjavellir geothermal field in SW-Iceland. Silencer equipment was used as noise sources, through which a double phase flow was discharged to the atmosphere. These sources emit noise levels with low frequency characteristics and according to measured noise, need distances longer than 160 m to reach reduced noise values on the order of 50-55 dB (A), the values recommended by the environmental legislation for residential areas. However, at Nesjavellir there are no communities located close to the well sites; therefore, the noise emissions do not constitute an environmental impact, except for the recreational areas close to Nesjavellir. The study also included calculation of noise using the Sound Plan Software, where noise levels were determined by modifying environmental variables such as ground type, relative humidity and inserting acoustic barriers close to the sources. The results indicated that a combination of soft ground at all well sites and acoustic barriers placed very near to the sources can attenuate the noise levels at short distances, when it is too expensive to modify the source design in operation projects. Therefore, it is recommended to carry out experimental testing of noise propagation by modifying environmental conditions for the purpose of verifying real noise values, and then to apply environmental measures to attenuate the noise impact produced by geothermal development.