The document discusses using life cycle assessment (LCA) as a tool for designing more sustainable cities. LCA can help address environmental problems by assessing the full life cycle impacts of city infrastructure and design. The document presents an LCA of natural gas distribution networks in neighborhoods with varying densities. Results show the environmental impact is four times higher in a low-density neighborhood compared to medium and high-density neighborhoods, mainly due to differences in network length. LCA is presented as an appropriate tool for guiding urban ecodesign and decision-making by providing a comprehensive view of environmental impacts.

1. Life Cycle Assessment as a Tool for Designing more Sustainable Cities Project funded by the Spanish Ministry of the Environment A042/2007/3-10.1. and the project cRRescendo within the EU 6th FWP. Research group on Sustainability and Environmental Prevention (SosteniPrA). Institute of Environmental Science and Technology (ICTA) Autonomous University of Barcelona (UAB) Jordi Oliver-Solà, Xavier Gabarrell, Joan Rieradevall April 2008

9. LCA as a tool for the ecodesign of cities “ All the ants on the planet, taken together, have a biomass greater than that of humans. Ants have been incredibly industrious for millions of years. Yet their productiveness nourishes plants, animals, and soil. Human industry has been in full swing for little over a century, yet it has brought about a decline in almost every ecosystem on the planet. Nature doesn’t have a design problem. People do.” McDonough i Braungart, 2002

15. Natural gas distribution networks Scenarios Neighbor- hood Street section Apartments Buildings Pipe length (m) Scenario Apartments per building Buildings Pipe length (m) 48 10 100 6,672 139 1,389 C 24 10 100 6,672 278 2,778 B 1 4 100 6,667 6,667 166,667 A

16. Natural gas distribution networks Detailed diagram

17. Results and discussion High relevance of local components and maintenance works 15 Boiler 50 Manometer 50 Tap 50 Downpipe Apartment 50 Closet 50 Gas meters and associated elements 50 Tap 50 Service line 50 PE-Cu transition Building 50 Trench works 50 Surface box 50 Pipe Neighborhood network Average lifespan (years) Component Subsystem

24. Thank you very much! Life Cycle Assessment as a Tool for Designing more Sustainable Cities Research group on Sustainability and Environmental Prevention (SosteniPrA). Institute of Environmental Science and Technology (ICTA) Autonomous University of Barcelona (UAB) Jordi Oliver-Solà, Xavier Gabarrell, Joan Rieradevall [email_address] April 2008 Project funded by the Spanish Ministry of the Environment A042/2007/3-10.1. and the project cRRescendo within the EU 6th FWP.