A renovation of the dam in Trängslet hydroelectric power plant is necessary for there to continue to be hydropower at the facility in the future. The power plant is located in Österdalälven in Älvdalen and is operated by Fortum. Trängslet is one of Sweden’s largest hydroelectric power plants with a reservoir stretching 70 km in length and has been operational since 1960.  The renovation of the dam will continue until 2024 and one part of the renovation is that bedrock must be blasted away in order to improve the water purification. The rock material should then be reused as reinforcement of the dam, instead of storing it. This contributes to a carbon dioxide reduction by not having to retrieve rock material from a nearby quarry. The purpose of the study was to identify which production method that produced the least amount of carbon dioxide from transport in the mass handling of rock materials from the blasting area, of three different presented transportation alternatives. The results show that the option Skanska uses today (option 1) provides a carbon dioxide reduction of approximately 58%, when the comparison has been made with option 2. A comparison was then made between options 1 and option 3 which showed that the reduction in carbon dioxide emissions was about 84%.  The study also shows that with the help of a carefully planned production method, carbon dioxide emissions can be reduced, and that Skanska today uses the most environmentally friendly option (option 1) for the project Trängslet. A further reduction in carbon dioxide emissions can be done by switching fuel for transport from what is used today (MK1 Diesel) to HVO Diesel 100, which would then reduce carbon dioxide emissions by up to 83%.