Figure 1.11 The Cluster Management of Waste

Distributed systems for omnidirectional fl ows: Achieving greater functionality for nodes and networks The integration of nodes and networks is achieved through distributed systems. In a traditional supply-oriented approach, the number of nodes is few; a single supply facility might be the only supply node, for example, and the distribution network may be a simple one-way hierarchy from a big facility node directly to users. A fully distributed system actually works in both directions and enables omnidirectional fl ows. The supply system may begin at or near the home, offi ce, or shop where the demand for services originates. Local and renewable options may be explored for on-site supply, storage, or treatment; roof-mounted technology may capture and store water, for example, or capture and convert sunshine. It is conceivable that public utilities may still own and manage technologies, but they are located on-site. If on-site facilities are not practical, suffi cient, or economical, the next choice is to examine options for the cluster, block, or neighborhood.

Economically, it is often viable to locate a signifi cant capacity in supply and treatment facilities at the neighborhood or district level or at the center of small clusters of mixed use buildings so that equipment may be well managed and used continuously (fi gure 1.11). Combined heat and power plants in Europe often operate at this scale and thereby provide power and heating across city districts. Another example might be septic tanks attached to buildings, which may be interconnected to a small inground wastewater treatment facility at a local park or to a high-rate composting vessel at the nearest recycling depot or community garden. Distributed systems make greater use of networking. Local networks for capturing water or generating power may allow nearby sites to share surpluses with others, creating a two-way micronetwork. Surplus energy (for instance) generated by a cluster of users may be stored for later use or sold back to a smart grid. Local networks may be nested within larger networks. In this way, the pattern changes to a system with many nodes serving clusters of users and connected through a complex network with omnidirectional fl ows. Distributed systems may cover large areas of the city, but the nodes are more numerous, and the networks are more adaptable.

The Rocky Mountain Institute’s pathbreaking and comprehensive work on the viability of distributed energy systems catalogues over

Figure 1.11 The Cluster Management of Waste

Source: Author elaboration (Sebastian Moffatt). Note: The scenario shown on the left is the common supply model, whereby solid waste is collected from many sources by a centralized trucking system and then processed at a large, remote facility. On the right, a two-way network evolves to eliminate waste within the cluster.

200 benefi ts (see Lovins and others 2002). The most signifi cant benefi ts relate to system modularity, which contributes to a reduction of economic and fi nancial risk by several orders of magnitude (fi gure 1.12). Other potential benefi ts from the integration of nodes and networks might include the reduced costs for land dedications and reductions in the characteristically large transmission and conversion losses. For many cities, a growing proportion of utility resources are being used in unproductive generation and distribution, especially because DSM has reduced the demand for services at each node. A distributed system not only helps to avoid these costs, but also may offl oad the costs of new facilities from taxpayers to developers and give developers a longterm interest in the effi ciency of neighborhoods. Other benefi ts from more distributed systems include the more incremental pace of investment that is shaped by demand, the more eff ective matching of capacity to existing load, and the lower vulnerability to whole-system collapses. As infrastructure facilities move close to buildings, so do the jobs, and the city becomes more effi cient and walkable. The proximity of facilities also increases the potential for almost all other types of integration (for example, recycling, looping of resource fl ows, multipurpose uses, and culturally distinct structures).

As demonstrated in a Worldwatch Institute case study (Bai 2006) on the City of Rizhao in Shandong Province, China, distributed solar water heating systems can be eff ective urban energy solutions, while also helping address social equity issues.

Spatial planning may also benefi t from distributed systems that make nodes of the population more self-reliant. This is the philosophy behind smart land uses such as mixed use walkable communities that provide easy access to transit, services, shops, and parks, rather than forcing everyone to travel to the city center or mall with the attendant costs of time, energy, and emissions. Multifunctionality: Serving diff erent ends by using common spaces and structures The integration of infrastructure facilities across sectors is achieved through multipurpose elements that serve diff erent sectors simultaneously or at diff erent times. A common example is the integration of energy and water systems. In many towns and cities, the largest single energy account in the community is for pumping municipal water from wells or water bodies. Sewage digesters also require large motors and energy expenses. Thus, saving water automatically means saving the energy required for water supply and sewage treatment. An integrated approach is the logical option.

The integration of energy and water can involve more than simply the shared effi ciency gains. The water system for the Olympic Village in Vancouver, Canada, for example, is closely integrated with the energy supply systems in the city. As the water travels down from the city’s mountain reservoirs, it turns a turbine within the pipes. The turbine creates electrici-

Solar Energy Systems in Rizhao, China

Rizhao, a city of about 350,000 people in northern China, is using solar energy to provide lighting and water heating. Starting in the early 1990s under a municipal government retrofi t program, the city required all buildings to install solar water heaters. After 15 years of effort, 99 percent of the households in the central district had obtained solar water heaters. Solar water heating now makes economic sense. The city has over a half-million square meters of solar water heating panels, the equivalent of about 0.5 megawatts produced by electric water heaters. Most traffi c signals and street and public park lights are powered by solar cells, reducing the city’s carbon emissions and local pollution. Using a solar water heater for 15 years costs about US$1,934 (Y 15,000), less than the cost of running a conventional electric heater, which equates to saving US$120 per household per year in an area where per capita incomes are lower than the national average. This achievement is the result of a convergence of four key factors: a regional government policy that promotes and fi nancially supports research; the development and deployment of solar water heating technologies; a new industry that takes the opportunity in stride; and city leadership that not only has a vision, but also leads in action and brings along other stakeholders.

Source: Bai (2006).