Building a circular economy

Abstract

The construction sector is one of the biggest contributors to global CO2 emissions and buildings account for a significant part of the energy use in Sweden. Population growth in combination with economic development is putting more pressure on the environment, resulting in escalating consumption trends and larger quantities of raw material extraction. Policies and directives are promoting a circular economy in material flows. Waste avoidance and reuse are priorities in the EU waste hierarchy. Environmental issues are apparent to be a subject of urgency and will conceivably remain problematic for future generations.

Drivers and barriers for implementing a circular model in the Swedish construction industry was studied with interviews, questionnaires and calculations. A fictive house was used as reference point in calculations and survey. In total, 19 interviews and questionnaires were performed. Indicating quality consistency, quality assurance, logistics, timeframes and availability to be the major barriers. Furthermore, the need for a coordinating actor in the reuse process is a reoccurring subject. An additional survey was distributed to all 290 municipalities in Sweden to investigate the flexibility in regulations addressing the poor energy performance in reused windows. The survey results show that using windows with U-values of 2.0 W/(m^2 ∙ K) is accepted if figures for ”installed effect”, ”average U-value” and ”EPpet" is within the limits regulated in the building codes.

Calculations on LCA and LCC was performed with the purpose of investigating the inbound energy in comparison to energy savings by installing a new ”low energy” window. Results indicate that even windows with bad energy performance are environmentally profitable in many cases when compared to the inbound energy of manufacturing a new high performing window. LCC results indicate that if the windows are to be reused and estimated to last 25 years, the cost involving restauration, transport, dismantling and installation is financially feasible up to around 70 000 SEK - 100 000 SEK depending on inflation and growth rates.

Concluding from interviews, the feasibility of incorporating circularity to the building sector in Sweden is highly dependent on timeframes. It is apparent that the reuse option must be presented at the earliest of stages, placing focus on contractors and architects. Also, building with the intent of dismantling is seen as a fundamental part of the circular model. Possible drivers are seen as a combination of government tax reductions on reused components and raised taxes on unsorted waste.

Popular Abstract

“By adding insulation, we lowered our annual energy use with....” *sigh*. This quest for never-ending improvements in energy performance is getting out of proportion. The struggle of making energy improvements in construction projects seems to be an obsession for the building sector, chased without any further consideration. But what if we told you that the common conception of environmental benefits in regard to renovations is not always the case. With increasing proportions of renewable energy sources being provided, the importance of embodied energy and carbon dioxide in materials is becoming a substantial aspect in the overall environmental impact. Calculations indicate that changing windows for pure environmental reasons could be unfeasible for up to 50 years in terms of inbound energy. By utilizing reused windows, financial savings of approximately 70 000 SEK – 100 000 SEK can be made, allowing for renovations and refurbishments.

The problem is simple. We are using more resources than we can afford. As the major contributors of emissions and use of raw materials, the building sector needs to re-assess current methods. The importance of circular models and reuse of materials and components are becoming more of a reality due to current environmental situations. It is important to remember that our resources are finite. With an additional three billion middleclass consumers expected by year 2030, growing urbanisation and population, the focus on circularity is apparent. The effects of implementing circularity in the construction sector would not only minimize raw material use but also reduce waste.

Our research aims to evaluate the drivers and barriers of implementing a circular model to the building sector. Through interviews and surveys, we concluded that the industry is seemingly positive for a change towards reusing building components. We are building with the intent of never disassembling structures and major components of a building, making it difficult in terms of reusability. As one respondent answered; ”Reuse is necessary for a sustainable future, but it requires building for future reuse, and the majority of structures are not built for that”. Through 19 semi-structured interviews/questionnaires and a survey distributed to all 290 municipalities in Sweden, we could evaluate the feasibility of reusing building components. In order to have a “bottom-up” approach to the reuse process, the attitudes of inspectors and flexibility of building procedures had to be investigated. Through the survey, law and regulations in combination with attitudes and incentives showed not to be problematic, and the process of implementing circular economy into the construction sector could be addressed. Windows and bricks were chosen as suitable test subjects when conducting calculations on LCC and LCA. Investigating the embodied carbon dioxide in a 12x12 dm window resulted in the conclusion of the importance regarding environmental aspects in energy sources. High proportions of clean electricity are widely available in Sweden, making feasibility difficult in regard to environmental impacts. The LCC calculations for the same windows were carried out in order to investigate the financial incitements of refurbishing and reusing windows. Different economical forecasts were made to present a sensitivity analysis. Bricks were investigated in terms of labor and resource intensity. This shows that the price-point of new bricks in combination with high labor-costs in Sweden are making financial aspects of reusing bricks difficult.

• author: Eryilmaz, Eray and Andersson, Simon
• supervisor: Jouri Kanters; Henrik Davidsson
• organization: Division of Energy and Building Design; Department of Architecture and Built Environment
• course: AEBM01 20181
• year: 2018
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering; Earth and Environmental Sciences
• keywords: Circular economy, Reuse, DfD, LCA, LCC.
• language: English
• id: 8957122
• date added to LUP: 2018-08-29 11:20:26
• date last changed: 2018-08-29 11:20:26