This project aims to enhance our understanding of the energy implications of urban form by connecting transport with the use of different types of buildings resulting from that transport. Urban form is intertwined with energy use and carbon emissions. Energy use per person in dense mega-cities, where residents live in apartment buildings and use public transportation, tends to be much smaller compared with urban sprawl areas, where residents live in detached houses and drive long distances. The division of urban areas into residential, commercial and industrial spaces also affects energy use. More energy is needed when homes, work places and shopping areas are separated as opposed to closer. One can think of the energy use of a given workplace or store as a network defined by how users of the building are coming from different areas. This networked energy model is developed for the Phoenix metropolitan area and also tracks how transport and building use changes over time as a community evolves.
The results of this project will help urban planners understand how to design more energy efficient and livable communities. For example, mixing residential, shopping and work areas can shorten driving distances, saving fuel and time. Even in an urban sprawl model, distributing home and shopping areas near one another can make walking and biking an attractive alternative for some trips. To make the results of the project usable and known to a broader group of stakeholders, a visualization tool is developed and integrated with educational and networking activities reaching urban planners.
Urban form has a significant influence on energy use and carbon emissions. Energy use per person in dense mega-cities, where residents live in apartment buildings and use public transportation, tends to be much smaller compared with sprawled suburban areas, where residents live in detached houses and drive long distances. The division of urban areas into of residential, commercial and industrial spaces also affects energy use. More energy is needed when homes, work places and shopping areas are separated as opposed to close together. In addition, often the energy that goes into building the urban structures and infrastructure including the supply chain of materials "from cradle to grave" required to build is ignored when estimating energy demands of neighborhoods. This project aims to enhance our understanding of the energy implications of urban form by connecting transport with the construction and use of different types of buildings connected by that transport. One can think of the energy embedded in structures and used for daily performance of a given workplace or store as a network defined by the location users of the buildings, i.e., households. This networked energy model including embodied energy is developed for the Phoenix metropolitan area. The objective was also to track how transport and building use changes over time as a community evolves. One set of findings improves our understanding of the embodied energy and carbon in urban form. The per capita embodied energy in the construction and maintenance of neighborhoods accounts for 2-4% of the national total. The 2% figure is for a denser single-family home neighborhood and the 4% figure is for a more sprawling one. Neighborhood design is thus relevant for determining net energy demand and carbon emission. It was also found that prior embodied energy assessments of buildings overestimate the contribution of operation. This is due to the routine exclusion of the contribution of supply chains from appliances, electronics and other goods associated with activities done in a building. These results suggest more attention is needed for building materials, construction and other supply chains. Results of comparison of travel behavior of city and suburban residents in Phoenix challenge the conventional notion that central city residents have shorter trips and choose shopping and work opportunities within a reasonable distance. Over time, central city residents seem to be traveling farther and there seems to be convergence of travel behavior between suburban and central city residents. Findings from the urban energy balance modeling study show that cooling is not only a function of vegetation and surface materials, but also dependent on the form and spatial arrangement of urban features. At the microscale, urban form has a larger impact on daytime temperatures than landscaping. In mid-afternoon, dense urban forms can create local cool islands.
