Life Cycle Sustainability Assessment of Energy renovations. A case-study of a multi-family building in Sweden

Abstract

Various renovations were applied to the existing post-war building stock of the so called “Swedish Million Program”, that were built during the 1965 and 1974 period. Only 20% of those buildings were renovated and still the rest of them remains in need of vast renovations, to mitigate the climatic impact of the existing building stock. Nowadays, the annual rate of large-scale renovation in EU countries including Sweden is only 0.4% to 1.2% per year. Consequently, there is a great need for large-scale renovations and due to the building’s high energy demand, the EU policies are driving the legislations and regulations towards
decreasing the environmental impact towards climate neutrality by 2050 for EU and 2045 for Sweden.

A building in South Sweden, from the Swedish Million Program was used as a case-study building, to apply several renovation solutions. The renovations were analysed from the economic but also from the environmental perspective. Three renovation packages were applied: envelope renovation, ventilation with heat recovery, and deep renovation. With Life Cycle Cost analysis, the investment and the operational costs were calculated using the Net Present Value and Life Cycle Profit. Then the Life Cycle Assessment was conducted, by using the shadow cost, i.e. a monetization value associated with the potential environmental impacts caused by the building. In the end the economic and environmental results were combined into one accumulated result into the Life Cycle Sustainability Assessment (LCSA) and to draw conclusions from the results.

It was found that the energy renovations were, in most cases, not profitable from the economic point of view. The heat recovery case resulted in a positive Life Cycle Profit and the cases with a negative Life Cycle Profit were the envelope renovation and the deep renovation. On the other hand, from the environmental perspective, all energy renovations were beneficial, due to the lower environmental impact, i.e. shadow cost, compared to the base case building. So, from the Life Cycle Sustainability Assessment, from the combination and the contribution of both the economic and environmental results, it was found that the heat recovery case was a profitable investment from both aspects. The LCSA results of the other cases, were resulted having higher values compared to the base case, since the LCC results dominated the LCA results, due to their high investments. Consequently, the LCC in the present study is determinant in the decision process. This kind of Life Cycle Sustainability Assessment would benefit the countries to the decision-making process on applying sustainable renovations to the existing building stock.

Popular Abstract

In Sweden, during the 1964 and 1975 period, almost one million residences were built during the so called “Swedish Million Program”. Approximately 20% of those buildings were successfully renovated but still the rest of them remain in need of large-scale renovations. Those buildings have a high energy demand compared to the new building standards and designs and therefore they have a high energy consumption and environmental impact. Most European countries need large-scale building renovations, due to the upcoming climatic changes but also since most buildings will remain habitable by 2050. However, only 0.4% to 1.2% is the annual rate of large-scale renovation in EU countries including Sweden. Consequently, there is a great need of large-scale renovations and due to the building’s high energy demand, the EU policies are driving the legislations and regulations towards a more sustainable and environmentally friendly framework, by following the climate neutralization goal by 2050 and for Sweden by 2045.

The purpose of the project is to combine the costs with the environmental impact of the selected renovations solutions and draw conclusions. The study was a continuation from a previous project where renovations were applied on a multi-family building towards passive house. The same building in South Sweden, from the Swedish Million Program was used as a case-study building, to apply several renovation solutions but also to weight the environmental impact of them. The several renovations were analysed from the economic, from the environmental perspective, but also from their combination of both. The examination was on the most important key-parameters and their interconnections between them, thus, to continue to the decision making-process. Three renovation packages were applied: The envelope renovation, i.e. thicker wall insulation, adding roof insulation, new passive house windows, the heat recovery, i.e. adding only heat recovery to the existing HVAC system and keeping the base case envelope construction, and the deep renovation, i.e. which was the combination of the envelope plus the heat recovery renovation.

Regarding the Life Cycle Cost analysis, the investment and the operational costs were calculated by using the Net Present Value and Life Cycle Profit. Then the Life Cycle Assessment was conducted, by using the Dutch approach, i.e. shadow cost, and by assigning a monetization value to the potential environmental impacts caused by the building, that the government or the society should pay to mitigate those damages. The economic and the environmental assessment was conducted considering a life cycle of 60 years. In the end, the economic and environmental results were combined into one result into the Life Cycle Sustainability Assessment and to draw conclusions from the results.

From the energy simulations applying the selected renovations, it was found that they had a better energy performance, by decreasing the energy need of the base case building. The best renovation was the deep renovation, followed by the envelope renovation and last was the heat recovery renovation. From the economic perspective, the heat recovery renovation, was resulted economic profitable, having a positive Life Cycle Profit, during the studied life cycle. The cases with economic loss were the deep renovation and the envelope renovation, resulting in negative Life Cycle Profits and high Net Present Values. On the other hand, from the environmental perspective, it was beneficial to conduct energy renovations, due to the lower environmental impact compared to the base case building. All the applied renovations resulted in lower shadow costs compared to the base case. The last part was the Life Cycle Sustainability Assessment, where both the economic and the environmental aspects were combined, and it was found that the heat recovery case resulted in having the lowest Life Cycle Sustainability Assessment result compared to the base case and to the other renovation cases.

Currently, there is a need for such studies and further research should be done assessing the key-parameters that play a critical role to those large-scale renovations. Economic, environmental but also social aspects should be considered and be balanced to reach to decision-making process and indeed take practical actions towards a more sustainable and environmentally friendly future.

• author: Betsi, Georgia
• supervisor: Ricardo Bernardo
• organization: Division of Energy and Building Design; Department of Architecture and Built Environment
• course: AEBM01 20211
• year: 2021
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Energy renovations, Life Cycle Assessment, Life Cycle Costing, Life Cycle Sustainability Assessment, Shadow cost
• language: English
• id: 9048751
• date added to LUP: 2021-06-03 16:14:48
• date last changed: 2021-06-03 16:14:48