In this paper the environmental impacts of the Colombian electrical grid operated by INTERCOLOMBIA are assessed during operation and maintenance phases. Energy transmission is necessary to the places where it is consumed as a consequence of energy generation. The methodology used here is Life Cycle Assessment (LCA) with ReCiPe 11 as impact assessment method and Ecoinvent 3.5, as dataset. Around 7200 km of power lines are evaluated (length of installation during 2016). The results show that for each power line kilometer, both, the land occupation and climate change are the most important impacts, comparing the Brazilian energy mix. According to the results of this analysis the environmental impact of power lines is greater than the impact of substations. The damage category with more impact was ecosystems for power lines, and human health for substations. The correlation with the Environmental Matrixes and the Green House Gases Inventory were also analyzed.