Resources from Waste: Wastewater Used for District Heating in Vancouver, B.C.

Facilities which housed 2,800 athletes and officials during the 2010 Vancouver Winter Olympics are being converted into an innovative district heating system – the first of its kind in North America. The newly developed high-rise waterfront residencies will utilize an onsite boiler to generate heat energy from sewage before sending it on to a treatment plant.

Heat and domestic hot water will be provided to residences in the development using recovered heat from sewage and wastewater. A boiler plant located across the street from the residencies will extract heat from the already warm sewage and wastewater and send the heat back to the housing units for use, generating huge energy savings and reductions in greenhouse gas emissions.

A New York Times article describes the process in greater detail:

The process extracts heat from previously strained sewage, which is typically at 18 to 20 degrees Celsius (64 to 68 degrees Fahrenheit), using an industrial heat pump, a refrigeration unit which draws thermal energy from the waste and feeds it into a hot water distribution network. A high-efficiency, insulated piping system, buried underground, distributes the water at 65 degrees Celsius to neighboring buildings. After circulating throughout the buildings the water returns to the energy center, some 15 degrees Celsius cooler, to be heated again.

This description of the system is somewhat confusing, so I’ll try to break it down a little more simply. There is a closed water distribution network which circulates water back and forth from the boiler plant and the district residencies. Heat which is extracted from wastewater is transferred into this circulating water network which then runs to the housing and is used as a heating source. After heat is transferred to the homes from this water network, the then cooler water returns back to the plant to be reheated by more wastewater. This water will circulate over and over again, being heated by the sewage before transferring the heat to the homes and then returning back to the boiler to start the cycle again.

Here is a picture diagram provided by the NEU depicting this process:

One feature on this new energy facility which I think is a great idea is the color changing LED lighting panel located at the tips of the five staggered height steel beams which you can see in the picture above (you can’t see the color in the picture, just the five steel beams). The color of these LED panels changes to display the amount of green energy being produced by the residents and the energy center. It serves as an art piece that improves the looks of the relatively drab wastewater treatment facility, while simultaneously raising awareness and educating locals about the energy generated at the plant. The New York Times article quotes Kieran McConnell, an N.E.U. systems engineer, in regards to this lighting system:

One of our intentions was to relay to residents how much energy they’re using, the idea being that if they’re aware of what they consume, they’ll be more inclined to turn down their thermostats or stop the water from running

The city of Vancouver’s sustainability webpage describes the environmental, social and economical benefits of this new system:

Environmental Benefits: The NEU has economies of scale and flexible infrastructure that can adapt to using a wide variety of renewable “waste energy” options that would otherwise not be available to an individual building heating system. Through its high system efficiencies and by using sewage heat recovery to supply approximately 70% of the annual energy demand, the NEU eliminates over 50% of the carbon emissions associated with the heating of buildings. In addition, the LEED™ buildings connected to the NEU further minimize energy demand and greenhouse gas emissions using high quality building envelope design and hot water radiant heating systems. Furthermore, the NEU utilizes surplus energy generated by solar thermal modules located on the rooftops of three Olympic Village buildings.

Social Benefits: Through the NEU’s use of renewable energy sources and flexibility to adapt to future energy technologies, it is anticipated that NEU customers will enjoy rate stability that outperforms conventional options. Also, the NEU supports the use of radiant hot water heating systems in buildings that provide customers with a higher level of comfort at a lower energy use, as compared to conventional space heating options. In addition, the NEU eliminates heat production equipment from SEFC buildings, creating more space for green roofs and reducing maintenance for building owners.

Economic Benefits: The NEU is a self-funded utility that will provide return on investment to the City’s tax payers, while at the same time providing competitive rates to NEU customers. The NEU helps building developers meet the energy efficiency and green building requirements for SEFC more cost effectively as compared to the use of distributed stand-alone green energy options, such as geo-exchange.

The transference of warm wastewater into a reusable heat energy is a perfect example of Integrated Resource Recovery. In fact, this process reminds me of one of my previous posts about Australia’s first hydro-electric sewage treatment plant, where energy is produced through a process of wastewater falling down a 60-meter shaft. The difference between these two facilities is the type of energy produced by the wastewater. In Canada, wastewater is used to produce heat, whereas in Australia wastewater produces electricity.

It would be interesting to see the combination of these two processes in one facility. For instance, would it be possible to drop the wastewater down a shaft to collect hydroelectricity (like in Australia) before running the water through the heat pump to generate heat (like in Vancouver). This combination could potentially allow a district to heat homes and run the lights simply from the collection and processing of wastewater.

For more information on this new wastewater heat production center in Vancouver, check out the city of Vancouver sustainability webpage.

Also, if you are interested in reading a bit more into district heating systems and the water-energy nexus in Canada check out this older blog post written by Bevan about innovative ways to utilize the energy embedded in Ontario’s water.