Miljöpåverkan vid en förstärkning av eltransmissionen Stärnö-Hemsjö – En förstudie

Sammanfattning: Blekinge Offshore AB is a company with intentions of building an offshore wind farm in the bay of Hanö, in southern Sweden. If the full-scale park is constructed a total of 7-8 TWh of electricity will be produced annually. From the land connection in Stärnö, municipality of Karlshamn, current power lines stretch 21 kilometers up to a junction in Hemsjö, municipality of Olofström. If the full-scale park is to be constructed a reinforcement of the current power lines is necessary. This reinforcement can either occur through an exchange in the airborne lines or through an underground cable. The strongest argument for underground wire is the effect on human’s environment and health, through the problems with high magnetic fields and effects on the landscape view. Even though the effects on health from high magnetic fields are not fully understood it should be treated with care and caution should be taken. Power lines which pass near residences should therefore either be underground or placed with care. The economic perspective creates the most important factor for reinforcement of current airborne wires. The cost for underground cable is 4-10 times higher than construction of an airborne wire and therefore strong arguments are needed in order to balance the large difference in price. The ecological effects depend on which alternative is chosen. An underground cable leads to a small power line corridor, which creates opportunities for new trees to grow. If the current airborne wire is kept the power line corridor will be larger. In this environment a habitat with potential of high biodiversity is created, thus making a larger corridor a positive factor. Regardless of which alternative that is chosen there will be species that are affected negatively as well as species that are affected positively. The total effect on the ecology close to power lines is therefore often neutral. Along the power line there are few areas where the reasons for underground cable are enough to motivate this option. It is only close to the community Gungvala, northwest of Asarum, municipality of Karlshamn, where underground wire is suggested. In three areas a further investigation is suggested, to determine whether underground wire or an alternative location for an airborne power line is the best option. These three areas are from the roundabout on route 29 to E-road 22, from Hannetorp to Torarp and west of lake Kärrsjön. In all other areas airborne wire is found to be the best alternative.