The Global Urbanist

News and analysis of cities around the world


Little Grids: how small-scale utilities could solve America’s infrastructure woes

Eric Zachrison explores the merits of thinking small, instead of big, when it comes to planning for basic public services.

Cities: Delhi, Chicago

Topics: Water, waste and sanitation, Local economic development, Sustainability, Community organisation

This first utility node is within a man-made hill in a park. The hill, park and temporary lake are part of the overall water management strategy for the city. Photo: Eric Zachrison
This sketch shows how the neighborhood utility clusters, each with its own anaerobic digester, water and waste treatment plants and sub-station, would be rolled out and gradually form redundancy loops. Because they are within the neighborhoods, much less energy is lost. A locavore movement for our utilities. Diagram ©PENC
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A few days ago in downtown Chicago, the drainage system couldn’t cope after it rained aggressively for 15 minutes. Many streets had standing water on them for hours afterwards even though there had been less than half-an-inch of rain.

That same day, Rebecca Casper, the Mayor of Idaho Falls, a small city in the American Midwest, addressed scientists and policymakers at the Intermountain Energy Summit, telling them to prepare for a blackout. Not the theoretical blackout the conferees were in town to discuss, but, rather, half the town was threatened with a loss of power after a delivery truck knocked over a utility pole a few miles away.

In cities all over the United States,energy, water and waste systems are in need of replacement. As these services reach the end of their useful life, demand is greater and operational costs are increasing, but budgets are stretched. State and local governments have invested significant resources in policy and planning initiatives to solve the problem with federal and professional taskforces looking at ways to rebuild our infrastructure by making it more flexible, resilient and able to accommodate continued growth.  

Most of the debate is centered on making infrastructure systems “smart”, such as by installing sensors and other equipment on existing power grids to track and adjust generation and distribution in order to save on costs when demand is low. While making existing systems “smarter” – or, as I like to say, “continuously monitored and dynamically adjusted” – is one way to make them more efficient, it is just the sexiest of many strategies that we should employ.

A significant part of the solution may lie in thinking small, rather than thinking big. A path with many potential advantages is to move away from the model of centralized city -or region-wide utilities- toward a network of smaller utility districts. In this model, small plants scattered throughout a municipality would handle the water, waste and energy demands from a certain area. By sharing resources and reusing waste in the same place it is generated, this model can maximize efficiency.

In California, recent legislation requires major energy utilities to incorporate energy generation and storage systems built by customers into their distribution grids.  This act, which is meant to encourage the development of alternative energy, may also encourage building owners and campuses to consider on-site generation more seriously because they’ll be able to sell the excess energy they produce. The great thing about the networked grid model is that it lends itself to such an approach. Moreover, reducing the distance electricity has to be transported lowers the amount of energy that is lost in transmission meaning that less energy has to be generated at the outset to meet demand.  If small-scale, focused energy generation in buildings and neighborhoods proliferates, one can imagine a future in which California won’t need to purchase another megawatt sized facility, ever.

Similarly, as more and more businesses and households separate food waste, technologies that convert organic waste into energy, such as anaerobic digestion and biogasification, could be used at the local level to support waste handling, energy production and horticulture.  

Promising evidence of the success of the networked approach can be found outside of the United States in rapidly urbanizing areas where infrastructure development happens on a fresh slate, without the sunk costs of existing infrastructure. In a recent project for the design of a greenfield city called Sports City, a new suburb of Delhi, other members of the design team, our client and I were surprised when this option proved to be the most economic and efficient.

After analysis of a number of scenarios, the developer, acting as de facto city management, determined that it would be best for both the short- and long-term to develop a network of neighborhood-scale utility nodes in which energy, water, recycling and waste services are located in the same facility or next to one another instead of in massive centralized plants at the outskirts, far from residents and users. The major advantages of this plan include reduced and phased development and operational costs, design flexibility to adjust for uncertainty and innovation, lower transmission losses and increased service redundancy.

By placing water and energy services in the neighborhoods, the designers predict the city will realize significant reductions in transmission losses.  Water and electricity need only be transported a few blocks instead of miles, translating to lower operational costs.  Co-locating the plants means that the large amount of electricity that is consumed by water and waste treatment plants is also transported a very short distance. Plus the waste of one process can be used to support other systems. In Sports City, waste heat from the utilities will be used to warm water for energy generation.

Additionally, smaller systems are easier to roll out on an as-needed basis and cost less upfront than large facilities. This means that a city does not have to base its investment decisions on projected economic and population growth that might come three, four or five decades down the line, if at all. Instead of building for tens of thousands of residents that might come, it can build for the thousands that will come. What’s more, a network of several small utility nodes is resilient. If one goes down for planned or unplanned reasons, those around it are able to pick up the slack, which means that most service outages are highly local.

Sports City’s utility engineers were most excited about the opportunity to adopt newer innovations at a rapid pace. As new technologies and processes become available, they can roll them out in new developments. The systems can become cheaper, more efficient, and cleaner incrementally, without waiting for a major overhaul. When residents and businesses produce green energy of their own, their systems won’t be outliers. Instead, the city’s grids can be built to incorporate them.  And the engineers can test two or three new technologies simultaneously in different neighborhoods. Or, if they recognize that one system is more appropriate than another in a specific area due to minor geographic or climatic variations, they can build the network accordingly.

Locally-oriented public services and utilities give us an opportunity to move away from decades-long, billion dollar investments based on growth projections that may or may not pan out. With smaller systems, the entire city of Idaho Falls probably would not have been at risk from an accident at one aging utility pole.  Given the rapid pace of technological change, the uncertainty of even near futures and the stretched budgets of municipalities, optimizing municipal investments through smaller and more focused efforts will increasingly become the “smart” way to gradually grow and replace our older systems. 


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