Towards low carbon buildings: A case study in Sweden

Abstract

This study comprehensively evaluated the global warming potential of an office building in a newly built Scandinavian neighbourhood seeking to reach sustainability. The primary objective of the research was to support the city authorities of Helsingborg by providing valuable insights into actual carbon emissions at the building level and proposing measures to minimize these emissions to achieve climate neutrality by 2030.
Life cycle assessment (LCA) calculations, based on the ZEB (Zero-Emission Building) complete method, were utilized to accomplish these aims. The results were then compared to those of other recently built office buildings with comparable construction specifications. Thereafter, the current gap to carbon neutrality and possible potential for improvement were estimated.
The study showed that, compared to similar buildings, the case study building performs better than the average value in carbon emission. With a comprehensive calculation and quantification to assess the climate impact of the study building, the gap to carbon neutrality of this building is about 500 kg CO₂e/m² with the average European emission value for electricity, and about 400 kg CO₂e/m² with the Helsingborg municipality emission value for energy. With the extensive implementation of these measures, the most favourable scenario demonstrated remarkable proximity to the carbon neutrality objective. However, it is essential to observe that the potential for emission reduction is substantially greater when a building is designed to attain carbon neutrality. Building materials contribute significantly to carbon emissions, exceeding the impact of operational energy consumption. A rapid transition away from conventional building materials becomes essential to achieve carbon neutrality.
In addition, carbon emissions can be effectively reduced by modifying building systems and materials, especially using biobased materials. However, additional research is necessary to address the complexities of accounting for biogenic carbon, end-of-life scenarios, and the potential difficulties of double counting negative carbon emissions.
This study concludes with essential considerations for attaining carbon neutrality in future construction projects. The results highlight the importance of prioritizing sustainable building materials and investigating carbon capture and storage technologies, such as biogenic carbon and biochar. Ultimately, the construction industry can effectively contribute to carbon neutrality objectives by placing environmental impact alongside financial concerns. Obtaining carbon neutrality in the building industry necessitates a multifaceted strategy that incorporates energy efficiency, low-carbon materials, and sustainable urban planning while taking into account the broader environmental context.

Popular Abstract

Building Towards Carbon Neutrality:
Bio-Based Material, CO2 Storage and Solar Power Harnessing
Introduction:
Imagine living in a city that has reached carbon neutrality and even helps fight climate change. That is the ambitious goal of Helsingborg, a Swedish city that wants to become carbon neutral by 2030. To achieve this, the city needs to make sure that its buildings are as green as possible. But how can we measure the environmental impact of a building? And how can we reduce it?
A team of researchers from Lund University has tried to answer these questions by studying an average newly built office building in Oceanhamnen, an in-development neighbourhood at Helsingborg, that aims to be sustainable. They used a method called Life Cycle Assessment (LCA) to calculate how much carbon dioxide, one of the main impactful climate change gas, the building emits during its whole life span, from the extraction of raw materials to the demolition and disposal of waste, and what could have been done in the design process to improve the performance of the building.
Structural Modifications for Sustainability
The research team significantly emphasised reducing the environmental impact of building materials by exploring various structural modifications to enhance the building's sustainability. Concrete and steel, stone wool insulation and outside glass finish were replaced by biobased material such as Cross-Laminated Timber (CLT) panels, straw insulation and outside wood finish. These modifications could have reduced the carbon footprint associated with the building’s construction and ensured a more eco-friendly future throughout the building’s lifespan.
Solar Panels: A Green Energy Solution
Maximising local electricity production by harnessing clean and renewable energy was also considered by integrating solar panels into the building's design. Researchers aimed to offset a substantial portion of Prisma's energy needs. The power generated by these panels is considered carbon-free, effectively reducing the building's reliance on the traditional electricity grid.
Green Roofs and Biochar: Nature's Allies
To further reduce carbon emissions, researchers considered the integration of carbon storage through biochar and green roof. Green roofs act as insulation layers, minimising energy consumption and serving as potential carbon sinks when properly managed. Biochar, produced from biobased material, was integrated into green roofs, implemented on land as fertilizer and water filtration material, and used as building materials in end-of-life scenarios. By transforming these into biochar, carbon could have been stored and avoided being released when the building will be dismantled.
The researchers found that average newly built office buildings in Sweden still have a long way to go to reach carbon neutrality. The main sources of carbon emissions derived from building materials, such as concrete, glass and steel. The researchers suggested that using more biobased materials, such as wood and straw, could significantly reduce greenhouse gas emissions.
Conclusion: A Path Towards Sustainable Construction
The study shows that achieving carbon neutrality in the building sector is not easy, but it may be possible when designing buildings with carbon neutrality in mind from the beginning of the process. The researchers hope their findings will inspire cities and developers to follow Helsingborg’s works on reducing carbon emissions and making their infrastructures more sustainable. By doing so, they can contribute to a greener future for everyone.

• author: Tran, Huynh Tuan and Delorme, Victor-Antoine
• supervisor: Ricardo Bernardo
• organization: Division of Energy and Building Design; Department of Architecture and Built Environment
• course: AEBM01 20231
• year: 2023
• type: H2 - Master's Degree (Two Years)
• subject: Earth and Environmental Sciences; Technology and Engineering
• keywords: Life cycle assessment, Environmental impact of building materials, Carbon neutrality, Biobased material, Biochar, Cross Laminated Timber, Biogenic carbon
• language: English
• id: 9121199
• date added to LUP: 2023-06-20 14:17:59
• date last changed: 2023-06-20 14:17:59