A 2019 report, prepared by the Global Covenant of Mayors for Climate and Energy together with the C40 Cities network, identified three critical greenhouse gas (GHG) reduction strategies for cities around the globe: (1) zero emission public transport and enhanced bus networks; (2) residential building energy retrofits; and (3) low carbon district energy networks. These three strategies all have important multiple benefits for sustainable cities in addition to carbon reductions, such as measurably improving overall health of citizens through air pollution reductions (by not burning fossil fuels) and considerable job creation opportunities. District energy systems were singled out in the global analysis because they are under-represented in energy sector planning, they have considerable carbon reduction and energy optimization potential, and they use proven technologies.
District energy systems (DES) are basically a network of insulated pipes, often installed underground in the right-of-way shared with other utilities, that distribute hot or cold water produced in central plants to multiple buildings in a district, neighbourhood or city. This means that individual buildings connected to the DES do not need to own and operate individual boilers, furnaces, electric heaters, or air conditioning units. This saves money and space for building owners and managers. Low carbon district energy systems can use thermal energy from the ground (often called geoexchange to describe utilizing ground heat from shallow sources such as less than 300 metres below the surface), harvest industrial waste heat or cold ocean or lake water. Maintaining less mechanical equipment in central plants and thermally connecting buildings to move energy allows for greater efficiency. The thermal grid complements the electrical grid in the transition to net zero communities as we fuel-switch away from fossil fuels so that the electrical grid need not be upgraded to accommodate the entire transition away from natural gas to heat homes and power certain industrial processes.
The Centre for Community Energy Transformation, together with Future Energy Oakville and Peel Region, is coordinating a panel session on low carbon district energy systems at the Ontario Geothermal Association conference on May 22, 2024. Panel members represent companies (Corix, Creative Energy and Enwave) designing, building, and operating DESs in Canada. A few of the projects they partnered to create are described below.
Etobicoke Civic Centre, Toronto – District energy by Enwave Energy Corporation
The City of Toronto has planned the Etobicoke Civic Centre Precinct (also known as the Bloor-Kipling Precinct) as a near zero emissions community. Enwave Energy Corporation will provide energy to the entire Bloor-Kipling Precinct through a district energy system. The Civic Centre is a mixed-use building on the 18 acre site that rises in nine volumes: five low rise and four high rise. The district energy plant will help the Civic Centre building achieve Toronto Green Standard Version 3 Tier 4 performance standards.
[Source: Shovels Go Into the Ground for New Etobicoke Civic Centre | UrbanToronto]
Minto’s North Oak Development, Oakville – District energy by Creative Energy
Minto Communities GTA and Creative Energy have partnered to develop a geoexchange community energy system that aims to fully decarbonize the space heating and cooling for the North Oak development. Creative Energy’s district energy system will replace per-building mechanical plants with a centralized supply of ambient and hot water to each building. This allows the ambient network to leverage site-wide energy sharing and 3 geothermal fields (which will be constructed in tandem with the development schedule) to enable in-suite heat pumps to supply space heating in the winter, and to eliminate the use of cooling towers for cooling in the summer. Most notably, Creative Energy’s solution will not require the use of any natural gas to provide space conditioning, as the boiler plant is reserved for domestic hot water heating and as a back-up for the geo-fields. As a result, the system is expected to reduce on-site fossil fuel use by 95% and avoid almost 1,000 tonnes of GHG emissions a year. In addition to being connected to the low carbon district energy system, the North Oak towers are also targeting EnergyStar® Multifamily High-Rise Certification.
Lulu Island Energy Company (LIEC), City of Richmond, BC – District energy partnerships between Corix and LIEC
The Lulu Island Energy Company (LIEC) is a wholly owned municipal corporation of the City of Richmond. It was established in 2014 to provide district energy services on behalf of the City. City Council regulates customer rates with direction that customer rates are competitive to conventional energy costs, based on the same level of service. LIEC currently provides service to two services areas with 7.3 million square feet of floor space (2024) connected to district energy infrastructure using a combination of geoexchange, air source heat pumps and temporary natural gas boiler plants. The service areas will eventually combine into one city-wide City Centre District Energy Utility serving over 50 million square feet of new development by 2050, using sewer heat as a primary energy source. A rigorous procurement process selected Corix to design, build, finance and operate the district energy systems under a unique partnership arrangement, including financing from the Canada Infrastructure Bank.
[Source: News – District Energy Expansion Project – City of Richmond, BC]