CLEAN AND RENEWABLE ENERGY
Fossil-based energy, i.e., coal, oil and gas, enable construction and operation of modern cities. High-rise buildings, mega-infrastructure, motor-vehicle transportation, and the importation of resources from widely dispersed hinterlands are all possible and essential in a global economy. Side effects, however, include local air pollution that can cause respiratory problems, depletion of global resources, and atmospheric accumulation of greenhouse gases.
The IES calls for clean and renewable energy that avoids negative impacts to ecosystems and the atmosphere, as well as human health in both the short and long-term. Energy consumed is also primarily generated within the local bioregion.
To achieve the Clean and Renewable Energy principle articulated in the IES requires re-thinking the way that modern cities are constructed and operated. Much can be achieved through better design of urban environments that enable dense mixing of residential and commercial land uses to create “access by proximity.” Urban right-of-ways coupled with intelligent design of buildings can create passive daylight penetration and shading according to the needs of the local climate. Thinking of buildings as an extension of the infrastructure system also reveals opportunities for waste-heat exchange, rainwater collection, and food growing opportunities (e.g., on rooftops). These approaches can help reduce the urban energy load by at least 40% (Walker and Rees 1997; Rees 2010).
The challenge of generating most of a city’s energy within its bioregion depends largely on three factors: i) the natural resources of the bioregion including its geophysical characteristics, ii) the design of the built environment including a variety of land uses, and iii) the socio-cultural demands of urban residents. These elements are the starting points for determining the supply and demand of the energy balance within the bioregion.
Clean and renewable energy sources include: sun, wind, water (e.g., tides, currents and gravity to produce hydropower), and biomass (ideally from waste sources including wood, crop residues and animal dung). Natural gas can also be generated from fermenting biomass, e.g., anaerobic processes that decompose food wastes. However, not all bioregions are created equal from a resource endowment perspective. Thanks to the availability of fossil fuels, many bioregions that are not well-suited to supporting large concentrations of people are now home to millions. Examples include desert cities such as Las Vegas and Phoenix in North America and Dubai in the Middle-East.
The socio-cultural demands of urban residents also play an important role. These are influenced to a great extent by income, driven by desires for luxury and status. Technology can help cities make more efficient use of available resources, but whether residents choose to live within the existing carrying capacity of the bioregion is largely a matter of personal choice if the financial means to exceed carrying capacity are within reach. Ecological footprint analysis reveals that most of a city’s energy metabolism is associated with its residents’ consumption of goods and services (Rees 2010).
Walker, L. and W.E. Rees. 1997. Urban Density and Ecological Footprints: An Analysis of Canadian Households, Chapter 8 in M. Roseland, ed., Eco-City Dimensions: Healthy Communities, Healthy Planet. Gabriola Island BC: New Society Publishers.
Rees, W.E. 2010. Getting Serious about Urban Sustainability: Eco-Footprints and the Vulnerability of Twenty-First-Century Cities, Chapter 5 in T. Bunting, P. Filion, and R. Walker, eds., Canadian Cities in Transition: New Directions in the Twenty-First Century. Don Mills, Ontario: Oxford University Press.