Sustainable systems: A look at district energy

In case you’re looking for validation that we’ve been having an unusually hot summer, the data doesn’t lie. According to Environment Canada, weather in Ottawa for July 2020 is on record to be the second hottest July since 1883, with the average temperature being 24.4 degrees Celsius.

Needless to say, it’s hard to stay comfortable in such a harsh, and widely variant, climate – feeling too hot one season to too cold the next. Heating & cooling our homes and work places is an ongoing challenge and consumes a significant amount of energy. When it comes to environmental sustainability, looking for alternative systems to efficiently meet our creature comfort needs while reducing energy requirements and greenhouse gas emissions is essential. This is where district energy systems come in.

What is district energy and where did it originate?

Simply put, district energy is a shared network of hot and cold water pipes, buried underground, that’s used to efficiently heat and cool buildings and communities. As a centralized system, buildings within the network don’t need to own and operate their own boilers, chillers and cooling towers - greatly minimizing building footprints and energy consumption. The system optimizes the heating and cooling load requirements for the entire network – often pumping heat from a place where it is not wanted to a place where it is needed, without any need for fossil fuel inputs. This results in outstanding energy efficiency and conservation.

Given how little this system has been used, it may be surprising that district energy is not a new concept. Its origins can be traced back the end of the 2nd century BC - to the invention of the hypocaust heating systems that powered the hot water baths of the ancient Roman Empire. Famously, a hot water distribution system in Chaudes-Aigues, France is regarded as one of the first real district heating systems, using geothermal energy to provide heat for about 30 houses in the 14th century.

Why didn’t modern civilization continue to use this efficient and environmentally sustainable technology?

Implementing a district energy system is a major infrastructure undertaking as it involves excavating a network of underground pipes between multiple buildings. Moving forward with a system like this requires buy-in from a variety of stakeholders, including property owners, regulators, developers, municipalities, and utility providers. Despite all the environmental benefits, the high price tags and hurdles for implementation have served as a deterrent. That being said, district energy is seeing a resurgence in popularity and becoming a preferred method thanks to its lower and energy-efficient operating costs, reduced supply disruptions and environmentally-sound method of heating and cooling buildings. Municipalities and property owners are intrigued by this ancient alternative energy technology.

Are there any areas in Ottawa leveraging district energy?

Right within our own backyard, we are seeing trailblazers who are intent on leveraging district energy. Zibi Community development planners are currently going above and beyond – undergoing plans to implement the region’s first zero-carbon district energy.

What’s the difference with a zero-carbon system, you say? What it means is that, whenever possible, it will optimize the use of already hot and cold water rather than solely relying on high-carbon energy sources. In the case of Zibi, cool water can be sourced from the Ottawa River, and hot water can be sourced and reused from nearby industrial buildings (post-industrial waste heat).

Their goal:  to develop the most sustainable community in Canada. And, for a hot day like today, we think that’s pretty cool.

To learn more about Zibi, how district energy will be leveraged, and the vision behind the development, be sure to check out the ThinkEnergy podcast episode “District Energy: Looking Back & Moving Forward,” featuring Jeff Westeinde, President of Zibi Canada and Founding partner of the THEIA Partnership.

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