Carbon Emission Factors of Geosynthetics: Comparability Assessment and Determination of Representative Values for the Finnish Market
Abbasian, Mojgan (2026)
2026
Master's Programme in Environmental Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
Hyväksymispäivämäärä
2026-09-07
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202609079567
https://urn.fi/URN:NBN:fi:tuni-202609079567
Tiivistelmä
Geosynthetics can reduce the carbon footprint of infrastructure construction by lowering the demand for natural aggregates. Quantifying that reduction requires reliable emission factors, and in Finland these are compiled in the national CO2data database. For geosynthetics the factors are drawn from Environmental Product Declarations, but differences in the rules, standards, databases, and assumptions behind individual declarations make the declarations difficult to compare, and it is unclear which values are representative of the products used on the Finnish market.
This thesis determined representative emission factors for the manufacturing of geosynthetics used in Finnish infrastructure, covering raw material supply, transport to the factory, and production up to the factory gate. A total of 72 Environmental Product Declarations, yielding 84 product entries, were screened against four comparability criteria and sorted into groups of products made from the same polymer and serving the same function. Within each group, the relationship between the declared emissions of a product and its mass per unit area was examined statistically. Transport to Finland was recalculated on a common basis, and 3 expert interviews with manufacturers and a program operator supported the documentary analysis.
The carbon footprint of a geosynthetic follows the polymer it is made from and the amount of material it contains. Expressed per kilogram of product, the factors ranged from 0.90 kg CO₂eq for recycled polyethylene grids to 4.44 for virgin polyester geotextiles, and within groups made from a single polymer the mass of the product explained 84% to 100% of the variation in emissions between products. Raw material supply accounted for 82% of the manufacturing footprint on average, recycled feedstock reduced emissions by 23% to 63%, and transport from the factory to Finland typically added less than 5%. Geomembranes and geosynthetic clay liners proved uniform enough for a single value to represent the group, although this rests on a small number of declarations, since not all products on the market are covered. Products whose footprint follows their mass, about three fifths of those examined, are better represented by a factor per kilogram applied to the mass of the specified product, which turns the strong mass relationship into a directly usable input. Multi-material composites are reported with the range of values found within the group, and products made from recycled material are kept separate from their virgin equivalents rather than averaged with them.
The method of screening and grouping developed here gives a representative emission factor for every product group examined, matched to the precision the underlying data supports, and it is transferable to other product groups and national databases. The main barrier to comparability is the heterogeneity of the declarations themselves, in their category rules, back-ground databases, and transport assumptions, so the value of such factors will grow as EPD practice matures and reporting becomes more consistent. Further work should compare geo-synthetic and conventional aggregate solutions quantitatively and extend the dataset where a product type rests on a single declaration.
This thesis determined representative emission factors for the manufacturing of geosynthetics used in Finnish infrastructure, covering raw material supply, transport to the factory, and production up to the factory gate. A total of 72 Environmental Product Declarations, yielding 84 product entries, were screened against four comparability criteria and sorted into groups of products made from the same polymer and serving the same function. Within each group, the relationship between the declared emissions of a product and its mass per unit area was examined statistically. Transport to Finland was recalculated on a common basis, and 3 expert interviews with manufacturers and a program operator supported the documentary analysis.
The carbon footprint of a geosynthetic follows the polymer it is made from and the amount of material it contains. Expressed per kilogram of product, the factors ranged from 0.90 kg CO₂eq for recycled polyethylene grids to 4.44 for virgin polyester geotextiles, and within groups made from a single polymer the mass of the product explained 84% to 100% of the variation in emissions between products. Raw material supply accounted for 82% of the manufacturing footprint on average, recycled feedstock reduced emissions by 23% to 63%, and transport from the factory to Finland typically added less than 5%. Geomembranes and geosynthetic clay liners proved uniform enough for a single value to represent the group, although this rests on a small number of declarations, since not all products on the market are covered. Products whose footprint follows their mass, about three fifths of those examined, are better represented by a factor per kilogram applied to the mass of the specified product, which turns the strong mass relationship into a directly usable input. Multi-material composites are reported with the range of values found within the group, and products made from recycled material are kept separate from their virgin equivalents rather than averaged with them.
The method of screening and grouping developed here gives a representative emission factor for every product group examined, matched to the precision the underlying data supports, and it is transferable to other product groups and national databases. The main barrier to comparability is the heterogeneity of the declarations themselves, in their category rules, back-ground databases, and transport assumptions, so the value of such factors will grow as EPD practice matures and reporting becomes more consistent. Further work should compare geo-synthetic and conventional aggregate solutions quantitatively and extend the dataset where a product type rests on a single declaration.