Impacts from canopy materials

The impact results are divided into canopy component categories. This makes it possible to investigate the impact of the various canopy components and see the contribution from different materials. The results presented in this chapter are from the impact of the scenario 2 canopy, which is the largest canopy of the two scenarios. Results for the canopy in scenario 1 can be found in appendix G.

The category called ETFE includes both the ETFE film and pipes. Datasets for ETFE foil was not available in the database, so polyvinyl fluoride film is used instead. Polyvinyl fluoride film has some of the same properties as ETFE foil, and is often used as a protection film for objects that are exposed to outdoor conditions (Ebnesajjad, 2012).

Figure 4.2.2 Canopy scenario 2 Climate Change

Figure 4.2.2 shows the aggregated climate change potential impact over the canopy’s lifetime of 50 years. The results show that the ETFE are responsible for the highest impact. Both the real ETFE film and the polyvinyl fluoride film that are used has a high flammable resistance.

The results show that the impact from the incineration of the polymer film is very large. It is

possible that the high climate change impact in material incineration of the ETFE can be related to the polymer films high flammable resistance.

The aggregated climate change impact from timber includes both structural timber and the large glued timber beam. The impact from timber will be negative because timber acts like bio mass when it is incinerated for producing district heating or electricity. The timber in this model has district heating as a next stage avoided product. The results show that the different future energy scenarios have a high influence on the aggregated impacts for timber. The difference between some of the scenarios are more than a factor of 2.

4.2.1.2. Ozone depletion

The structural timber and the glued timber beam in the canopy have the largest impact related to ozone depletion potential as shown in figure 4.2.3. The impact is negative, which means that there will be an avoided impact. The detailed dynamic plots that can be found in appendix H, shows that the negative impact happens in the end of life stage.

Figure 4.2.3 Canopy scenario 2 Ozone Depletion

The impact in the production stages of timber are relatively small. The negative impact is most likely related to the incineration of waste wood for district heating production. The results show that the future energy scenarios for district heating has a high influence on the amount of avoided kg CFC-11 (trichlorofluoromethane) equivalents. The total impact for the large canopy will be negative for all five scenarios. Legato will have the highest negative of

-0.0376 kg CFC-11 equivalents. A European person equivalent in relation to ozone depletion potential is 0.022 kg CFC-11 equivalents, according to the ReCiPe Hierarchist. This means that that the total avoided impact in the Legato scenario will be the same as 1.7 European person equivalents in relation to ozone depletion potential. The standard scenario will have the lowest avoided impact of the 5 scenarios, which is 0.63 European person equivalents.

4.2.1.3. Photochemical oxidant formation

The ETFE materials has the highest impact of all canopy materials related to photochemical oxidant formation. The impact unit of POF is kg NMVOC (Non-methane volatile organic compound) which represents a range of different methane hydrocarbons. These Non-methane hydrocarbons are normally used in the production of crude oil. The Polyvinyl fluoride material that is used instead of ETFE is a material that is based on oil products. Some of the main compounds in the polyvinyl fluoride film are Non-methane hydrocarbons. Most of the impact from Polyvinyl fluoride film happens in the production phase. Some of these non-methane hydrocarbons are emitted when the polyvinyl fluoride film is burned in the end of life, which also gives a large impact in the end of life from the incineration. The avoided impacts from district heating are still a little bit larger, so the impacts in the end of life stages will still be negative. ETFE film is based on some other non-methane hydrocarbons. So it cannot be confirmed that ETFE and Polyvinyl fluoride film will have the same impact related to photochemical oxidation formation.

Figure 4.2.4 Canopy scenario 2 Photochemical Oxidant Formation

The aluminum profiles have the highest impact in the production stages. Aluminum has a high recovery rate with a high efficiency of the recovery process, which means that the negative impact from avoided products in the end of life compensates, so that the total impact of all stages in the aluminum profiles are generally low compared to ETFE and Glass. The timber materials will again contribute with a negative impact, because the timber is incinerated for district heating production. Again, it can be seen that the dynamic scenarios have a high influence on the total impact of the timber scenarios. The dynamic influence of the ETFE materials are much smaller. The reason for this is that most of the impacts happened in the production phase, which is not dynamic like the end of life phases.

Again, the Legato scenario have the highest impact, which will be the same as 11.5 European person equivalents. The Forte scenarios have the lowest impact which is 9.6 European person equivalents.

4.2.1.4.

The terrestrial acidification (TA) covers the deposition of inorganic substances related to SO2, NOx and NH3. The unit for TA is kg SO2 equivalents, where NOx substances contributes with a factor of 0.56, while NH3 substances contributes with a factor of 2.45 (Goedkoop, 2013).

Figure 4.2.5 Canopy scenario 2 Terrestrial Acidification -200.00

0.00 200.00 400.00 600.00 800.00 1000.00

ETFE Silicone sealing

Aluminium profiles

Glass Timber Pump Steel

kg SO2eq

Standard Forte Legato Espressivo Vivace

The distribution of TA impacts in the different materials categories are similar to the distribution of the impacts related to photochemical oxidation formation. One of the largest differences is that the dynamic scenarios behave differently related to TA. The standard scenario is now the scenario with the lowest impact. The results in figure 4.2.5 shows that the standard scenarios has the highest avoided impact related to timber by the lowest impact related to the ETFE. The scenario with the highest impact is again the Legato scenario which results in a total of 30.4 European person equivalents, while the standard scenario has 27.6 European person equivalents.

4.2.1.5.

The substances included in freshwater eutrophication are phosphorus (P) and nitrogen (N), where phosphorus is used as the reference unit. The emissions in freshwater eutrophication will normally emerge from sewage treatment plants or fertilizer and manure used in agriculture (Goedkoop, 2013).

Figure 4.2.6 Canopy scenario 2 Freshwater Eutrophication

The impacts in figure 4.2.6 shows that the scenario has a large influence on the aggregated impacts. This large deviation between the scenarios indicates that the impact occurs in the district heating system. While the impacts between the scenarios are different from the other impact categories, the pattern in impact between the different materials flows is very similar to the other impact categories.

Legato is still the scenario with the highest aggregated impact of 11 European person equivalents while Forte has the lowest aggregated impact with 4.25 European person equivalents.

4.2.2. Avoided renovation materials