Urban

Getting Started

There is increasing interest in understanding cities as an ecosystem, particularly through the use of  Urban Strategies to ensure sustainable urban development.  LCA is increasingly used to assess the sustainability of urban environments. To date, a rather limited number of urban environmental issues have been addressed using LCA. Should you choose to tackle an “urban” LCA project, the two primary issues with sufficient available information (enough for conducting a comparative LCA) are outlined below.

Image Courtesy of Jimfbleak via Wikimedia Commons

Living Wall – Image Courtesy of Jimfbleak via Wikimedia Commons

Green Building

Urban buildings have a large environmental footprint and have been the focus of many LCA studies.  This topic may be approached from several different perspectives but remember to choose studies that enable strong, quantitative comparisons.

A good overview of the subject area is provided by:

– Ortiz, O., Castells, F., & Sonnemann, G. (2009). Sustainability in the construction industry: A review of recent developments based on LCA. Construction and Building Materials, 23(1), 28–39.

who completed a meta-analysis of LCA’s of the construction industry.

We recommend you focus your study by undertaking a comparative LCA on a very focused sub-topic such as the two outlined below:

Wood vs. Concrete?

In North America, wood-framed construction is often used for houses and low rise apartment buildings. In many other countries reinforced concrete is used for the same purpose. Several LCA studies have been conducted to compare the environmental benefits of each system. The following papers provide sufficient information on this subject for you to complete a comparative LCA.

The following papers provide a good starting point for these issues:

– Werner, F., & Richter, K. (2007). Wooden Building Products in Comparative LCA. A Literature Review. Int J LCA, 12(7), 470–479.

– Gustavsson, L., Joelsson, A., & Sathre, R. (2010). Life cycle primary energy use and carbon emission of an eight-storey wood-framed apartment building. Energy and Buildings, 42(2), 230–242.

– Gustavsson, L., & Sathre, R. (2006). Variability in energy and carbon dioxide balances of wood and concrete building materials. Building and Environment, 41(7), 940–951.

– Gustavsson, L., & Sathre, R. (2011). Energy and CO2 analysis of wood substitution in construction. Climatic Change, 105(1-2), 129–153. doi:10.1007/s10584-010-9876-8

– Wang, L., Toppinen, A., & Juslin, H. (2014). Use of wood in green building: a study of expert perspectives from the UK. Journal of Cleaner Production, 65, 350–361.

Green roofing and living walls

The use of plants to provide ‘green’ roofs and walls is a rapidly developing trend in cities in the developed world. A review of the benefits of these systems is provided here:

Currie and Bass 2010, Greater London Authority 2008 (show complete cite)

Several studies that compare the environmental footprints of green roofs (or green walls) with standard conventional systems for roofing (or walls) have recently been published. While several of these studies have some shortcomings, they do enable the most important attributes of each system to be quantified. If you choose this topic, you will be required to clearly describe the impacts of the study’s limitations on the conclusions that you draw.

The following papers provide a good starting point for these issues:

– Kosareo, L., & Ries, R. (2007). Comparative environmental life cycle assessment of green roofs. Building and Environment, 42(7), 2606–2613.

– Saiz, S., Kennedy, C., Bass, B., & Pressnail, K. (2006). Comparative Life Cycle Assessment of Standard and Green Roofs. Environmental Science & Technology, 40(13), 4312–4316.

– Ottelé, M., Perini, K., Fraaij, A. L. A., Haas, E. M., & Raiteri, R. (2011). Comparative life cycle analysis for green façades and living wall systems. Energy and Buildings, 43(12), 3419–3429.

The topics for the two comparative LCAs outlined above will have enough information available to complete a reasonable project. Remember, however, that these papers provide only a starting point, and your project’s data sources should not be restricted to the publications listed above.

If you wish to pursue other green building topics, you need to demonstrate to us that you can find sufficient information to satisfactorily complete the study. In these cases, Dr McFarlane is happy to help you with the data mining and assessing the feasibility of a different green building LCA theme.

Recycling and Green Garbage

Understanding solid waste management (i.e., garbage!) is more challenging than you may think. Despite numerous studies of options for recycling and reuse of solid waste from urban communities, a wide variety of conclusions have been reached on what might be considered the “best” options. A recent meta-analysis cites 200+ studies (Laurent et al 2014), yet only 15 were considered rigorous or well-designed studies from an LCA perspective. Local circumstances can also greatly influence LCA results. For example, the composition of local waste and nature of disposal options make it very difficult to generalize.

The following papers provide a good starting point for these issues:

– Assamoi, B., & Lawryshyn, Y. (2012). The environmental comparison of landfilling vs. incineration of MSW accounting for waste diversion. Waste Management, 32(5), 1019–1030.

– Cherubini, F., Bargigli, S., & Ulgiati, S. (2009). Life cycle assessment (LCA) of waste management strategies: Landfilling, sorting plant and incineration. Energy, 34(12), 2116–2123.

– Banar, M., Cokaygil, Z., & Ozkan, A. (2009). Life cycle assessment of solid waste management options for Eskisehir, Turkey. Waste Management, 29(1), 54–62.

– Iriarte, A., Gabarrell, X., & Rieradevall, J. (2009). LCA of selective waste collection systems in dense urban areas. Waste Management, 29(2), 903–914.

– Menikpura, S. N. M., Gheewala, S. H., & Bonnet, S. (2012). Framework for life cycle sustainability assessment of municipal solid waste management systems with an application to a case study in Thailand. Waste Management & Research, 0(0), 1–12.

Most research on this topic examines urban cities and towns in the developed world. Our recommendation is that you undertake a comparative LCA that compares and contrasts the challenges of green recycling in one developed nation and one developing country.

Other Interesting Links

List of Urban Resilience Resources