Ecological Modelling 363 (2017) 157–171 Contents lists available at ScienceDirect Ecological Modelling journa l h om epa ge: www.elsevier.com/locate/ecolmodel Building emergy analysis of Manhattan: Density parameters for high-density and high-rise developments Jae Min Lee ∗ , William W. Braham PennDesign, University of Pennsylvania, 210S. 34th Street, Philadelphia, PA 19104, United States a r t i c l e i n f o Article history: Received 20 December 2016 Received in revised form 15 August 2017 Accepted 16 August 2017 Keywords: Emergy synthesis Self-organization Sustainable urban form Square foot based building material quantity a b s t r a c t To better understand how cities work, this study performs emergy (spelled with an “m”) synthesis of buildings on Manhattan Island. Conventional emergy studies have focused on much larger unit of analy- sis; however, architects, urban designers, and policymakers are operating on a smaller scale of building, block, neighborhood, and district. This study contributes to overcoming the scale and resolution mis- match between the macro- and micro-levels. Overall emergy for entire buildings on Manhattan Island is computed by adopting square-foot-base building cost estimation technique to emergy synthesis. We found that high-density and high-rise developments can achieve their maximum empower at the range of 1–5 Floor Area Ratio (FAR; an indicator of development density computed as total building floor area divided by total parcel area) and building height under 40 stories. © 2017 Elsevier B.V. All rights reserved. 1. Introduction With the increasing threats of climate change and steady increase in urban populations, sustainability has become a cen- tral focus of contemporary urban planning. Urban planners have emphasized a comprehensive approach in dealing with sustainabil- ity, including environmental durability, economic soundness, and social diversity (Berke, 2002, p. 30). However, actual policy inter- ventions have focused on actionable solutions for discrete problems in building and transportation to conserve energy. A good exam- ple is the recent interest in autonomous electric cars. Instead of addressing a comprehensive change in systems to reorganize urban settlements for self-sufficiency, electric car initiatives intend to replace gasoline-fueled cars with electric cars that use electricity from renewable sources. This limited approach fails to address the underlying problems of dispersed settlement patterns and other urban issues of exclusion and class separation. Urban issues are rarely isolated, wholly interconnected with each other (Odum, 2007; McHarg, 1969). For example, a commu- nity with higher density and mixed land use reduces the need for and the distance to travel (Jenks and Jones, 2010). As communities are connected with the city center and other communities, peo- ple have better access to public transit, further reducing transport energy (Cervero, 1998). With improved access and connectivity, the city center benefits from increased diversity and specialized labor that leads to economic growth through the agglomeration ∗ Corresponding author. E-mail address: jaemlee@upenn.edu (J.M. Lee). economy (Jacobs, 1961; Glaeser, 2011). Cities are complex ecolog- ical, economic, and social systems whose tendencies dramatically exceed the intentions of planners, politicians, and citizens. There- fore, a more comprehensive approach is necessary to understand the dynamics among density, land use, and transportation in cities. What is an appropriate density, mix of land uses, and configura- tion of connectivity to minimize resource intake while continuing to be productive? What is an appropriate level of energy consump- tion per capita? This study seeks to answer these questions by analyzing the energy flow of buildings in Manhattan. We use the techniques of emergy (with an “m”) analysis to understand the interaction among urban form matrices; the four urban form matri- ces include density, land use mix, connectivity, and accessibility. Different accounting methods such as exergy analysis, embodied energy analysis, and life cycle analysis (LCA) each have their place, and each considers different boundaries of analysis. Emergy anal- ysis considers the entire upstream contributions of work, energy, and materials, including environmental energies, which are typi- cally discounted or considered to be free (Buranakarn, 1998; Brown and Buranakarn, 2003). Emergy analysis is more than another sus- tainability metric to be compared to norms or established as a goal; it is a research methodology for understanding the structure and purpose of complex, self-organizing systems. By evaluating the total inputs, outputs, and potential environment impacts of a product or process (Srinivasan and Moe, 2015), this comprehensive energy accounting method helps us to understand the hierarchies and interactions that emerge as systems grow, develop, and adapt to changing circumstances. In this respect, emergy and life-cycle concept provide insight into the nature of urban form and the total resource flows used to sustain it. http://dx.doi.org/10.1016/j.ecolmodel.2017.08.014 0304-3800/© 2017 Elsevier B.V. All rights reserved.