The Carbon Efficient City: Building Blocks to Cool Our Planet

8. On-Site Life Cycles

105 I n some ways buildings and neighborhoods operate like living organisms. They require inputs like water and energy, which travel through their massive circulatory systems of plumbing and wiring, and at the end of that process , they output wastes. Most of us are used to thinking of these input and output systems in a linear way: we pay monthly bills for the water and energy that come into our homes, and we send outputs down the drain. “On-site life cycles” refers to the idea that energy and potable water can be generated, used or transformed, and treated within a fairly small system boundary before being released back to the surroundings in a harmless way. Although some of the technologies for achieving this outcome are still in the developmental stages, many others have been proven and are well established, particularly in cities outside the United States, where the need for compact, decentralized, resource-efficient infrastructure has spurred innovation and implementation. On-site life cycles are fundamentally concerned with access and infrastructure , and in that way this principle is parallel to the notion of complete neighborhoods described in chapter 6. But whereas complete neighborhoods are about access to consumer goods and services and social networks, the prinCHAPTEr 8 on-sITE lIFE CyClEs The first rule of sustainability is to align with natural forces, or at least not try to defy them. —Paul Hawken CHAPTEr 8 106 ciple of on-site life cycles is about access to water, energy, and sanitation. Just as access to goods and services could be achieved either with a great deal of infrastructure and driving about, or with relatively little carbon impact, so can access to water, energy, and sanitation occur with either a great deal of delivery infrastructure or a relatively smaller, localized amount. A key difference between the two principles, however, is that in our modern economy the supply chain of many goods has become global because of production advantages in certain parts of the world. On the other hand, most inhabitable places have local access to fresh water (rain, wells, surface water) and energy (solar, wind, combustion). In many places the concept of on-site life cycles for energy and water may be much more achievable than the notion of neighborhood-scale supply chains for goods. Off-site life cycles—which is to say, centralization of fresh water and energy generation and centralized treatment of sewage—are relatively new inventions in human history. Up until a few hundred years ago, most people settled in places near fresh water and in places where solar energy or combustion energy (usually in the form of forests) was adequate to support food growth and provide heat. In other words, water and energy were delivered with no infrastructure at all. As urban areas grew, local water sources became polluted, adjacent forests were depleted, and untreated surface sewage became a public health problem. This led to centralized sewage and garbage collection, remotely sourced and distributed water, and finally the development of electrical and other energy distribution infrastructures. These developments have made much greater densities of human habitation possible. But this infrastructure comes at a high economic price. The “magic” of water flowing from faucets and emptying down the drain and of energy available from an outlet or a gas main has made us much less aware of our consumption of both the resources themselves and the infrastructure capacity required to bring them to us. Citywide water systems carry an enormous energy cost. Municipalities around the United States spend between 25 and 50 percent of their total electricity budgets on conveying and treating water and wastewater.1 Likewise, combustion power plants often use large amounts of water to cool the plant machinery. So the two resource problems go hand in hand. According to the National Resource Defense Council, reducing water use is one of the cheapest strategies for conserving energy, and in a virtuous circle conserving energy would further reduce demand for municipal water.2 Unfortunately, inefficiencies are rampant in our modern water systems, and one of the main reasons for this is that their costs are not transparent to ON-SITE LIFE CYCLES 107 the end user. Much of the current infrastructure in the United States was built with various influxes of federal subsidies and grants and is more than fifty years old. Many water systems need replacement, and some leak away more than 25 percent of...