Barriers and opportunities of fast-growing biobased material use in buildings

Limiting global warming to 1.5°C requires immediate and drastic reductions in greenhouse gas (GHG) emissions. A significant contributor to anthropogenic global GHG emissions is the production of building materials. Biobased materials offer the potential to reduce such emissions and could be deployed in the short term. Timber construction has received the main attention from policy and industry. However, the implementation of timber construction at the global scale is constrained by the availability of sustainably managed forest supplies. A viable alternative is fast-growing plants and the use of agricultural waste products. These can be deployed faster and are better aligned to local supplies of biomass and demands from the building sector. Fast-growing materials are generally able to achieve net-cooling impacts much faster due to their short rotation periods. The GHG emissions due to the production of biogenic building material can be compensated by regrowth of the new (replacement) plant and, overall, this will absorb CO2 from the atmosphere. A range of biogenic materials can be promoted and used as insulation materials and structural materials. Policy relevance Materials play an important part of the transition to a low carbon society, especially as many existing construction materials have large amounts of ‘embodied carbon’ in their manufacture. Given the need to rapidly reduce GHG emissions, public policies can promote a rapid transition to low carbon biogenic materials. The use of fast-growing biogenic materials for use in construction products can create carbon-neutral or even carbon-negative products. The use of biogenic materials in construction materials delivers larger GHG savings than their use in other sectors (e.g. biofuels). The use of these materials can be scaled up quickly due to their short rotation period. An integrated policy approach is needed that provides synergy between the energy, industry, housing and agriculture sectors to encourage the use of biobased materials.ISSN:2632-665

Barriers and opportunities of fast-growing biobased material use in buildings

Limiting global warming to 1.5°C requires immediate and drastic reductions in greenhouse gas (GHG) emissions. A significant contributor to anthropogenic global GHG emissions is the production of building materials. Biobased materials offer the potential to reduce such emissions and could be deployed in the short term. Timber construction has received the main attention from policy and industry. However, the implementation of timber construction at the global scale is constrained by the availability of sustainably managed forest supplies. A viable alternative is fast-growing plants and the use of agricultural waste products. These can be deployed faster and are better aligned to local supplies of biomass and demands from the building sector. Fast-growing materials are generally able to achieve net-cooling impacts much faster due to their short rotation periods. The GHG emissions due to the production of biogenic building material can be compensated by regrowth of the new (replacement) plant and, overall, this will absorb CO2 from the atmosphere. A range of biogenic materials can be promoted and used as insulation materials and structural materials

Climate-effective use of straw in the EU bioeconomy—comparing avoided and delayed emissions in the agricultural, energy and construction sectors

A transformation towards a bioeconomy is needed to reduce the environmental impacts and resource requirements of different industries. However, considering the finiteness of land and biomass, such a transition requires strategizing resource and land allocation towards activities that yield maximum environmental benefit. This paper aims to develop a resource-based comparative indicator between economic sectors to enable optimal use of biobased resources. A new methodology is proposed to analyze the climate effectiveness of using straw in the agricultural, energy and construction sectors. For this purpose, avoided and delayed emissions are analyzed for different use cases of straw and then compared. Considering only avoided emissions, the use of straw as a feedstock for bioelectricity has the highest climate effectiveness (930 kg CO2 eq./tstraw). Considering only temporal carbon storage, straw-based insulation in buildings has the highest climate effectiveness (881 kg CO2 eq./tstraw). Combining avoided and delayed emissions, the use of straw-based insulation has the highest climate effectiveness (1344 kg CO2 eq./tstraw). Today EU-Policies incentives the use of straw in the agricultural sector and the energy sector, neglecting the benefit from its use in the construction sector. The results can support policymakers' trans-sectoral incentives, where agriculture by-products are diverted towards the use of biomass that most boost economic activities and trigger maximum environmental benefit, given the local circumstances.ISSN:1748-9326ISSN:1748-931

Fleet-based LCA applied to the building sector - Environmental and economic analysis of retrofit strategies

CO2 emissions need to be reduced by 40% in 2030 in Portugal as an intermediate target of the Paris Agreement. This challenging goal is expected to be achieved through incentive-based regulations and voluntary actions. This study improves the understanding of renovation strategies to reduce emissions caused by the built environment. A fleet-based Life Cycle Assessment (fb-LCA) is adapted and applied to the building sector. Fb-LCA integrates LCA and a fleet model to describe stocks and flows associated with a class of products over time. The method is tested for a neighbourhood in Lisbon, Portugal. The analysis compares 3 scenarios of dynamic renovation rates for the next 30 years: business as usual, a public economic incentive to renovate, and mandatory renovation. Different technology scenarios including bio-based ones, are compared. Among the latter, alternative material solutions, e.g. insulation cork boards, are emerging, providing carbon sequestration. Results highlight the environmental benefits of bio-based materials considering the temporal profile of renovation activity. Furthermore, the cost and sensitivity analysis help stakeholders to justify retrofit actions from an environmental and economic point of view. The adaptation of a fb-LCA approach proves to be an easy-to-use method to assess technology options and policy scenarios at a neighbourhood scale.ISSN:1755131

A matter of speed: The impact of material choice in post-disaster reconstruction

The effects of urbanization and climate change are dangerously converging. The most affected populations are the urban poor, settled in informal settlements vulnerable to increasingly frequent disasters. This severely contributes to the existing housing gap of these regions, already struggling with housing demand. The speed of shelter delivery becomes key for an efficient response in order to prevent spontaneous informal resettlements on unsafe lands. The present study aims to understand the impact of material choice on post-disaster shelters delivery through a multiscale analysis of construction speed. The scales considered are: Constructive technology, Shelter Unit and Post-disaster settlement. At the the Constructive technology scale, nine different reconstruction solutions for the Nepal earthquake are compared, covering a range from local to industrialized. Successively, twelve shelter designs by the International Federation of the Red Cross have been studied under the same lens at the Shelter unit scale and for Post-disaster settlements. The study identifies a clear correlation between material procurement and speed at the constructive technology scale. At the shelter scale, this correlation becomes secondary and construction time is seriously impacted by the complexity of roof design. Moving to the settlement scale, the choice of local over industrialized materials seems to drive the speed again. The study indicates how a multiscale approach is necessary to analyze the impacts of material selection, providing efficient guidelines for post-disaster reconstruction. Beyond that, it highlights that effective reconstruction can be developed with diverse materials, but its emergency responsiveness can seriously be compromised by a non-appropriate design

Land availability in Europe for a radical shift toward bio-based construction

The renovation and construction of buildings presents an opportunity for climate change mitigation in urban environments. Bio-based construction is particularly promising since the plant's sequestered carbon offsets the building's carbon emissions. However, the required land to cultivate suitable biomass and the feasibility of environmentally sustainable materials for resilient cities should be understood. This study analyzes timber, straw, hemp and cork construction and renovation in Europe. A prediction-based model, tuned-up on four systems (built environment, natural environment, carbon balance, industrial processing), converts construction activities until 2050 into required material, embodied land and carbon storage. A novel material-land nexus concept analyzes the required land for bio-based construction. Land transformation is not analyzed. The aim is to evaluate the biomass supply considering the current cross-sectoral use of land in Europe. The results indicate that current forests and wheat plantations are more than sufficient for supplying construction materials. Straw seems better than timber, in terms of resource availability and carbon storage potential. Cork is only favorable locally in southern dry countries. The current legal limitations hinder hemp's potential at a large scale. A wider application of bio-based materials remains unrealistic until an appropriate legal framework is provided

Bridging the gap – A database tool for BIM-based circularity assessment

The concept of circular economy attracts attention across sectors. Since construction materials are the single largest material stock and flow, there is a particular interest from research and policy to apply the circularity concept to buildings. Large quantities of construction and demolition waste end up in landfill, despite new EU legislation that requires a 70% recovery rate. There is a gap between this ambitious goal and the reality of the construction industry. Building Information Modelling (BIM) has the potential to improve building design and construction processes for an increased recovery of materials. However, insufficient data, inconsistent methods and interoperability issues inhibit BIM application to unfold its full potential in circularity assessments. This paper introduces the CirBIM database framework. It provides BIM users with the required robust data to improve the circularity throughout the building's life cycle: from the design phase throughout renovation activities to the end-of-life stage. The paper proposes a new workflow of building circularity assessment, describe the architecture of the new database tool, and recommends relevant data sources and information models to streamline data mining processes. The new database tool is exemplified through application to a case study building in Portugal, emphasizing the need for different metrics and the need of integration of the end-of-life scenarios in the building design stage.ISSN:1755-1315ISSN:1755-130

Dynamic life cycle assessment of straw-based renovation: A case study from a Portuguese neighbourhood

ISSN:1755-1315ISSN:1755-130