District energy can be a tool to build efficient communities, not just efficient buildings.
The global environmental crisis we’re facing is in large part due to how we’ve designed and built our communities. It’s a result of how we use resources, produce products, develop land, construct infrastructure, supply services and connect places.
Cities represent less than one percent of the earth’s total surface, but urban activities around the world generate close to 80 per cent of all carbon dioxide emissions, and consume nearly 75 per cent of all energy produced. Transportation accounts for a significant portion of the energy consumed in Canadian cities, but the built environment still represents 30-40 per cent of all energy consumed in Canada.
Yet when buildings and cities are properly designed, they can encourage and support a low-carbon, energy-efficient and prosperous lifestyle. Increasingly, communities in Canada are incorporating sustainable urbanization practices into planning activities: land uses that support higher density populations, localized energy generation, enhanced local ecosystem integrity (including the use of green infrastructure to minimize flooding), public transit and improved energy, water and material efficiency in the built environment. It makes sense, then, that cities would look at using community energy management strategies that incorporate district energy.
District energy appeared in Canada in the 1880s, providing heating to the university, hospital and government complexes in London, Ontario. Today, there are over 116 systems operating across the country. District energy works to manage the energy needs of a community at the building level. As a management system, it helps accommodate and meet the different energy demands of buildings and industries that use energy in different amounts and patterns.
To help communities address their energy supply and infrastructure challenges, the Canadian Urban Institute, Canadian District Energy Association, and the Toronto Atmospheric Fund formed the Urban Energy Solutions (UES) infrastructure research partnership. The UES initiative set out to identify the challenges to the advancement of district energy across Canada, and demonstrate how district energy has a direct role in contributing to local community infrastructure and energy conservation in urban regions.
The two-year initiative resulted in, among other things, the development of tools and products to assist policy makers, corporate decision-makers, investors, building owners, planners, environmental managers and organizations with generating ideas on how to advance district energy in communities across Canada (visit www.cdea.ca/resources for more information) .
The work also highlighted that district energy is doing much more than meeting heating and cooling demands. It’s also leading communities to achieve economic growth and land-use objectives, such as compact urban from, while also reducing greenhouse gas (GHG) emissions. An example of this is the district energy system operating in Markham, Ontario.
Markham has been working to integrate the concepts of sustainable development into its planning activities since the late’90s. The town was among the early adopters of New Urbanism, which supports the practice of compact and land-efficient urban form, higher density development, a wide range and mix of land uses, a pedestrian-friendly and connected grid pattern of streets, and high quality urban design. These principles continue to guide Markham’s growth, but are now broadening to address concerns with GHG emissions and energy consumption.
Early in the planning and development of Markham Town Centre, the town identified district energy as an important component for achieving energy reduction goals and land use development objectives. They recognized that a district energy system could help lower energy consumption in the town centre by 20-30 per cent, while also contributing to the concentration of urban form, particularly the mixing of high-density residential and commercial buildings.
The initiative also revealed that district energy was being used increasingly by communities across Canada to meet goals like intensification, re-urbanization, community economic development or sustainable energy planning. For instance, the City of North Vancouver incorporated district energy as part of a larger strategy to revitalize and redevelop city-owned lands along the waterfront. In this case, district energy provided an incentive for developers and investors by reducing the need for capital investments in constructing heating and cooling systems. The city attracted much-needed investment in the downtown while also moving toward meeting energy and GHG reduction goals.
For the Town of Revelstoke in British Columbia, district energy became an integral component of a long-term strategy for economic advancement and retention. New restrictions on the burning of wood residues threatened to force a vital local sawmill to close or relocate, but the town created a public-private partnership with the owners of the sawmill, which led to the development of a renewable fuelled (wood biomass) district energy system. The system meets the economic needs of the sawmill operator by providing an affordable heat source to operate wood drying kilns and supplies the town with a largely free source of heat for local businesses, institutions and municipal operations.
Tools to beat the barriers
Among the recent developments that have emerged in both the United States and Canada to advance the cause of district energy is the importance placed on integrated design and planning. A number of communities have undertaken or are engaged in the development of community energy plans.
Traditionally, energy planning for communities kept the optimization of district energy systems and the energy performance for buildings separate.
Today, there is general agreement that to ensure a district energy system achieves the highest efficiency levels possible, design teams for a new building connecting to a system need to consider the performance metrics of a district energy system from day one of a project. That means assessing the performance of a building and energy supply systems as a single integrated system. This approach for evaluating district energy was recently adopted by the Canada Green Building Council (CaGBC) with the Application Guide for Campus and Multiple Buildings, which incorporates an Interpretation Guide for District Energy Systems.
Following an integrated process can lead to innovative design in the development of a building, as in the case of a residential development connecting to the Lower Lonsdale District Energy system in North Vancouver. The system operator incorporated a cooling service to address consumer demands for centralized air conditioning. The end result was that the residential developer applied passive design techniques to meet cooling requirements, eliminating the need for air conditioning.
When broadened out to the community level, integrated energy planning can provide communities with an entirely different approach to achieving energy needs by assessing opportunities to lower energy use across an entire community, improve the energy efficiency and operating performance of a building, effectively turn community “wastes” (biomass, sewer heat or landfill gas) into energy assets. When integrated with community planning, district energy becomes an energy management strategy that meets sustainable development objectives.
Brent Gilmour is a project manager with the Canadian Urban Institute. He’s responsible for CUI’s urban energy practice.
This article appears in our July-August 2008 Issue
