The overall construction industry is responsible for more than a third of global resource consumption, 40% of energy consumption, 36% of CO2 emissions and 1/3 of all wastes in EU . This sends a clear message that the construction industry must enhance the transition towards more sustainable construction materials. Wood-based construction materials are considered as alternatives to conventional ones (concrete and steel) due to their lower environmental impact, moreover, wood is seen as material which can give a significant contribution to fight against climate change in terms of CO2 reduction.
The Sengon tree – also called Albasia (Paraserianthes Falcataria) – a native Indonesian fast-growing species (harvest time in 7-10 years), attracted particular attention in recent years due to excellent mechanical properties. Offering a high potential for sustainable lightweight construction. Scientifically documented results on the use of Albasia are only available to a limited extent due to its novelty. This opens space for deep examination of the material, and possibility to derive answers on environmental impact of Albasia processing and usage.
A step forward in that direction is a master’s thesis research conducted at Pforzheim University in Germany. The assessment object of screening LCA was 1m3 of Albasia plywood in the frame of the so-called ‘’cradle to gate’’ concept. Therefore, included processes steps were:
- Growing and Harvesting,
- Transport in Indonesia,
- Plywood Production and
- Transport to Europe.
Important notice is that screening LCA is not a complete LCA, rather it helps to identify hotspots in the life cycle of a product and point out data gaps. Therefore, the results are not final and numbers may change when the complete and detailed LCA is performed. However, the significance of showing in which direction research should go in the future is great.
The examined impacts are:
- Climate Change and
Climate Change is selected because of its global importance and it is expressed in kg CO2 equivalent (kg CO₂-eq). However, other greenhouse gas (GHG) emissions than carbon emissions (CO₂) cause climate change as well (methane (CH₄) or laughing gas (N₂O)). To get a single metric for climate change impact category the other GHG are also expressed in kg CO₂-eq.
Acidification is exeminated because it represents the impact of forestry activities. Acidification potential (AP) provides a measure of the decrease in the pH-value of rainwater and fog, which has the effect of ecosystem damage for example, nutrients being washed out of soils and increased solubility of metals into soils. AP refers to the compounds that are precursors to acid rain. These include sulfur dioxide (SO2), nitrogen oxides (NOx), nitrogen monoxide (NO), nitrogen dioxide (N2O), and other various substances. AP is usually characterized by SO2-equivalence.
For acidification, the total emissions were 5,58 kg SO2-eq/m3. More than a half of the emissions (51%) are related to the plywood production (glue and the packaging plywood). Moreover, emissions associated with transport of plywood were also high (transport in Indonesia has a share of 15%). It is interesting that forestry activities, growing and harvesting, have the lowest emissions – less than a 1%.
- Climate change
Total emissions of climate gases were 696,12 kg CO2-eq/m3. Similar to acidification, the highest emissions were coming from plywood production – 66% or 459 kg CO2-eq. Not only glue had a strong influence, but also the additional plywood used for packaging gave a significant contribution. One third third of the emissions belongs to transport in Indonesia and 21% of the emissions are emitted during the transport to Germany. Again, lowest emission were from forestry activities – less than 1%)
According to standard DIN EN 16449, the amount of CO2 stored in 1 m3 of Albasia plywood was calculated and compared to the emissions of production and transport in order to answer the question – is more CO2 released into the atmosphere during production than sequestered?
During production 696 kg CO2-eq is released into the atmosphere while 1 m3 of plywood stores 544 kg of CO2. Therefore, 152 kg CO2-eq more is emitted than sequestered.
Although on the first sight it looks that production of Alabisa plywood is not carbon neutral, it is still far better than CO2 emissions from structural steel or concrete production (8831.2 and 288.0 kg CO2 eq / m3, respectively). Furthermore, there is plenty of space to improve the process of the product, which brings optimism and motivation to continue developing strategies for emissions reduction.
The Screening LCA pointed out plywood production plants as a main emission hotspot in growing-production-shipping process, for both environmental impact categories – climate change and acidification. Clearly, to reduce emissions the focus must be on the process of plywood production. There are many actions which can be taken in this case, some of them are:
- Reduction of glue usage during optimal setting of machines or usage of more sustainable glues.
- Check if plywood for packaging is necessary, check if thinner boards can be used or if it can be substituted with carton boards.
- Reduction of electricity consumption during optimal setting of machines, use of electricity that comes from renewable sources, investment in new, more efficient machines and/or installation of photovoltaics.
Finally, it is important to notice again – these are not final results. Once detailed LCA is performed, the above mentioned actions can be modeled and then it will be possible to have more reliable results and a clear picture of Albasia plywood environmental performance. However, there is no doubt and this can be seen from this research, Albasia has a great potential to make a significant contribution to the reduction of CO2 emissions that comes from the construction industry. Hence, there are high expectations from future research activities in the area of LCA of Albasia wood.