Adrienne T. Cooper
Florida A&M University, Biological and Agricultural Systems Engineering
adrienne.cooper@famu.edu
Sustainable infrastructure development has thus far been focused on conformance to a set of rules or guidelines. For example, LEED and BREEAM set national standards for Green Building Certification in the U.S. and UK respectively, and the Energy Star Rating System (US) has been developed for appliances and products. However, these must be used in conjunction with other indicators to evaluate sustainability. Principles of sustainability have been developed to address socio-ecological elements using a thermodynamic basis to identify the influence of society on nature and material exchange. Principles of green engineering have also been established that provide a guide for development. However, none of these principles are clearly applicable to infrastructure, and achievement of the principles is not readily measurable. The use of sustainability indices provides for measurable outcomes.
A sustainable design necessarily includes the ability of the system to recover from perturbations, whether they are natural, anthropogenic or technogenic. This system resiliency has traditionally been viewed as separate from sustainability, but more recently they have come to be recognized as two sides of the same coin. The interdependence of urban infrastructural elements adds an additional layer of complexity to be considered in evaluation and design.
We discuss the use of EMERGY methodology for the development of indices of resilience, with an eye toward a combined index dealing with both sustainability and resilience of water and wastewater infrastructure systems. We have provided a preliminary definition of a resiliency index that indicates the total time of a system to recover (TTR), a function of both the physical and the social aspects of the system as well as the EMERGY output (transformity). The physical and social recovery of the system are captured in a physical recovery index (PRI) and a social recovery index (SRI).
The presentation by Dr. Cooper was quite informative. As environmental engineers, it is very important for us to look at the economic, social and environmental aspects of the sustainability systems that we design. One example of the consequences of how we negatively use our environment is clearly seen in the social injustices that occur to different groups of people. To ensure that our systems cover these three aspects, we need to pay close attention to the boundary of the system, sources and methods used to gather data. I would have liked to hear more about emergy, as it seems like an interesting topic.
ReplyDeleteAccording to Dr. Cooper, it is quite a challenge to measure sustainability, which is affected by a number of diverse parameters within the realms of economics, social justice and the environment.
ReplyDeleteEconomic parameters such as Profit, GDP, Return on Investment, Opportunity Cost play a large role. A paradigm shift is necessary to incorporate true costs within sustainability calculations, and consider long term benefits as opposed to quick returns.
Social Justice is not easy to measure, but equally important. 1/6 of the world's population is responsible for the emission of 55% of all the CO2, and another 1/6 is responsible for only 3% of these emissions. The former 1/6 do not and will not feel the consequences of these emissions as much as the latter 1/6. Another inequity lies in the access to sanitation - only 40% of the rural population in developing countries had access to sanitation in 2004. Economic and social inequity have impacts on the environment.
Data gathering is another issue, since not all locations in the world have reliable data, or no data at all. Indicators of social status are variable among different locations, as well. Number of homes with air conditioning could be an indicator of social status in Florida, but it would not be as strong of an indicator up North.
Infrastructure is highly interdependent. There are few or no operational boundaries, rapidly changing technology, dynamic and increasing risks, heightened threat levels and increasing uncertainty, and large amounts of data and information.
The traditional approach to infrastructure management is events driven, incorporating disaster avoidance and the management of safety & risk. Resilient infrastructure, on the other hand, relies on self-organization, technological innovations and adaptability. It is the ability of a system to recover from a disturbance, retaining basic functions. However, resiliency usually does not mean the system is going to bounce back to where it was before the disturbance.
Emergy is "the energy required directly and indirectly to make something function", and was coined by H.T. Odum and Scienceman in mid 1980s. It is basically a common measure for different forms of energy.