District Energy Systems


"District energy is to heating and cooling buildings, what public transit is to moving people"

For Toronto to achieve its aggressive emissions reduction target of 80% by 2050, major emissions reductions are essential. With transportation the big effect is to get people out of their cars and into electrified transit networks. With buildings the big effect is to connect buildings to low-carbon thermal networks, also known as district energy systems.

What is District Energy?

District energy (DE) is a thermal energy distribution system for multiple buildings at the neighbourhood scale. A district energy system consists of a:

  • Heating and cooling centre; and
  • Thermal network of pipes connecting groups of buildings

Heating and cooling centres can utilize various low-carbon energy sources such as solar thermal, sewer heat, biogas, cold lake water, biomass and the ground. Efficient combined heat & power (CHP) plants can power new transit and the heat can be recovered to heat nearby buildings. Co-locating district energy systems with municipal and other infrastructure is important to accessing these energy sources.


  Sewer Heat Recovery      Lake Water Cooling     Geo-exchange + Solar Thermal    CHP + Electric Transit

(click pictures to enlarge)

Toronto has a long history using district energy:

  • The University of Toronto DE system began operation in 1912 and has grown to serve most of the campus.
  • Enwave operates a steam system and, since 2004, the world's largest lake water cooling system. It uses Lake Ontario water to cool over 60 buildings Downtown including the Air Canada Centre, City Hall, Royal Bank Plaza, and Queen's Park.
  • The revitalization of Regent Park (see images below) included redevelopment of the existing thermal network. The system will eventually provide heating, cooling, and electricity to more than 50 buildings.

Regent Park District Energy System

The Energy Centre is in the basement of the residential building at 252 Sackville St.

Opportunities for New DE Systems in Toronto

As with most infrastructure, including transit, high-density urban areas support the implementation of DE systems. Therefore, opportunities for DE generally align with the growth areas designated in the City of Toronto's Official Plan, including:

  • Centres and Avenues
  • Mixed Use Areas and Regeneration Areas
  • Institutional Areas

A City of Toronto DE node scan identified over 27 locations across the city that could potentially support a new DE system.

Click for interactive map

Benefits of DE  

Cost-effective emissions reductions

District energy systems are key to reducing emissions from buildings, as shown below:

The thermal network is a game changer with respect to urban energy solutions. As an infrastructure solution, not a technology, the network creates the economies of scale that allow for large emissions reductions at a low cost compared to efforts at the scale of individual buildings (see graph below). Less carbon-intensive fuel sources can be integrated at the energy centre with virtually no impact on connected buildings.  


Comparison of the avoided costs of building and district (i.e. neighbourhood) scale solutions

Local economic benefits

  • DE systems are cost-competitive with typical heating and cooling systems. Connected buildings do not require heating and cooling equipment and avoid all the associated operations and maintenance expenses. 
  • DE systems are designed to grow incrementally over time as a neighbourhood develops, it avoids the need for large capital investments, making it attractive to private investors.
  • As a local energy solution, more of the energy dollars spent are recirculated within the community that the DE system serves.


Energy benefits

  • DE systems, especially when they include power production (e.g. combined heat and power) reduce pressure on existing energy infrastructure.
  • Resilience to power outages is strengthened as connected buildings will continue to be heated/cooled if the electricity grid fails.

District Energy Framework

Best Practice and Policies Research - EED staff worked with Reshape Strategies to review best practices and inform future policy development by the City to advance district energy development.

 The main objectives of the study were to:

  • Research best practices of municipal district energy policies in other cities
  • Explain the rationale for district energy
  • Summarize the current state of district energy in Toronto
  • Provide a Menu of Policy Options


For more information or to get a copy of the full report please contact us here:


Workshop - EED staff hosted a workshop on June 23rd at Regent Park with staff from other City of Toronto Divisions and Agencies to discuss the key framework elements.

Staff Report - EED staff reported to Executive Committee on October 26th to inform Councillors of a strategy to scale-up and accelerate thermal network development. The report was adopted with minor amendments and staff will report back in Q2 2017.     


District Energy-Ready Guidelines

In order to be able to eventually connect new buildings to a DE system that has not yet been constructed, they must be District Energy-Ready. This key elements of a DE-ready building are:

1)    Ability to supply thermal energy from ground level;

2)    Adequate space at or below ground level for a future energy transfer station;

3)    An easement between the mechanical room and the property line to allow for thermal piping;

4)    Two-way pipes placed in the building to carry the thermal energy from the district energy network to the section in the building where the future energy transfer station will be located;

5)    A low temperature hydronic heating system that is compatible (i.e. large temperature differential or ∆T) with a district energy system in order to reduce the pipe sizes and associated valves, fittings, etc.; and

6)    Appropriate thermal energy metering. 

The Guideline provides information to building developers and owners, architects, and engineers to design buildings that are DE-ready.

Exhibition Place

The Exhibition Place DE system is the City of Toronto's first concrete step towards widespread implementation of a DE system across the city. In addition to delivering immediate benefits to Exhibition Place and the new hotel being constructed on the grounds, this project represents the City leading by example with its own assets in order to attract investment in new DE system development city-wide. Construction of the DE system was completed in early 2016 and it will be fully operational when the hotel opens in late 2016.       


Click to view/download PDF

Westwood Theatre Lands

Reconfiguration of Etobicoke's Six Points Interchange is providing an opportunity for the City to lead by example with its own assets to initiate development of a new DE system. In coordination with Transportation Services, pipes are being installed to connect future development parcels on the City-owned Westwood Theatre Lands, a brownfield that will be developed by Build Toronto. As the area is developed over time, the thermal network will be completed and energy centres implemented to create a new DE system.  


Click to view/download PDF