Transportskedets betydelse för klimatpåverkan vid materialval i en gatu- och VA-anläggning : En jämförande livscykelanalys av importerade och lokalt producerade VA-ledningar, brunnar, betäckningar, kantstenar och överbyggnadsmaterial

Sammanfattning

The construction sector significantly contributes to global greenhouse gas emissions, but material choices often prioritize technical properties and cost over climate impact, partly because life cycle assessments (LCAs) frequently limit system boundaries to the product stage (A1–A3). This study investigates how expanded system boundaries, including transport (A4) and installation (A5), affect the climate footprint and cost when choosing between imported and locally produced materials in a construction project. A quantitative case study was conducted on a fictional one-kilometer street in Uppsala, Sweden, including road structure, pipes, manholes, and curbstones. Climate calculations were performed using Prodikt with EPD data, and cost calculations using Bidcon with official price lists. Results show that including A4–A5 increases the total climate footprint by 23–125 percent for street scenarios comparedto A1–A3 alone, with individual products showing even larger increases. Imported granite curbstones saw a 1 517 percent increase, where transport accounted for 94 percent of emissions. Heavy materials like concrete and granite are transport-dominated even over short distances, while lighter materials can be imported longer distances without transport emissions becoming decisive. The relationship between climate impact and cost is complex: for some products, the cheapest option also has the lowest climate impact, while for others, climate-smart choices incur significant additional costs. The study shows that future LCAsshould include at least stages A1–A5 to avoid misleading comparisons.