Life Cycle Assessment of Recently Constructed “Climate Protection Neighbourhoods” – Which Lessons can be Drawn?

Abstract The results of a life cycle assessment of five recently finished housing projects in Northern Germany - all of them part of two certified climate protection neighbourhoods - point out the necessity of combining a variety of different carbon reduction approaches in order to reach carbon neutrality. The analysis presented here focuses on both, embodied and operational carbon emissions, as well as embodied and operational energy, over a period of 50 years. Both residential areas examined do not tap the full potential of their environmental impact reduction as they focus on single strategies only: one development limits the reduction of carbon emissions for heating and domestic hot water supply to a max. of 7.5 kg GHG emissions per m2 and year, by means of conventional solid construction. For the other estate the developers encouraged timber construction by requiring a minimum share of the construction volume of 70% timber. Comparing both approaches shows, that climate friendly construction can only be achieved by combining different ways and means, e.g. easily demountable hence reusable timber structures with a high level of energy efficiency and a carbon free heat supply. The results drawn from this study are designated to serve as a basis for discussion of the development of ambitious and climate responsible housing standards in Bremen.