Industrial waste heat: An undervalued source of energy

Quebec is sitting on an energy source that’s all too often overlooked: waste heat emissions. Generated primarily from industrial processes, wastewater treatment plants, data centres and incinerators, this thermal waste is a significant source of energy that can—and should—be recovered and reused. Let’s look at how waste heat can be repurposed to meet the energy needs of buildings and industrial operations.

What is waste heat?

Waste heat is unused thermal energy generated by industrial processes or other activities. It’s typically released into the environment. In Quebec, this residual heat comes from:

• Waste treatment plants: Nearly 1,000 heat-generating plants
• Industrial sites: Nearly 200 facilities, including incinerators
• Landfills: Approximately 25 sites
• Data centres: Around 23 facilities
• Off-grid networks and cogeneration plants: Around 20 networks and 20 power plants

Untapped energy potential

The waste heat produced in Quebec is significant, amounting to 300 petajoules (PJ) or the equivalent of 83 terawatt-hours (TWh) of energy. That’s nearly half of the province’s current energy consumption and almost enough for the additional 100 TWh Quebec needs to attain carbon neutrality by 2050. For example:

• Industrial facilities: Waste heat from industrial facilities can amount to several hundred megawatts (MW) of thermal power. For example, a manufacturing plant can release up to 50 MW of heat.
• Water treatment plants: Water treatment plants can release anywhere between 1 and 5 MW of heat.
• Data centres: The average data centre can release roughly 10 MW of heat.

How can this energy be repurposed?

Recovering thermal energy for use in building heating systems:

1. District heating systems: Recovered heat can be integrated into district heating networks, thereby reducing dependence on fossil fuels. For example, a district heating system can use residual thermal energy to heat thousands of homes.
   
2. Heat pumps: Heat pumps can capture waste heat so that it can be used for industrial processes or heating systems for buildings, greenhouses or other purposes.
   

Industrial applications:

1. Preheating raw materials: Waste heat can be used to pretreat raw materials in industrial processes, which reduces primary energy consumption.
2. Process steam generation: Waste heat can be upgraded to high temperatures using mechanical recompression and then used as a direct source of process steam.
3. Cogeneration: Cogeneration plants can use waste heat to generate electricity and useful heat simultaneously. Overall energy efficiency is improved, though it remains limited.

Benefits of waste heat recovery

• Lower greenhouse gas emissions: Using waste heat instead of fossil fuels to produce energy results in lower carbon emissions.
• Energy savings: By recovering waste heat, business and communities can reduce their primary energy consumption and save money.
• Cost savings: Although waste heat is often considered a free or inexpensive source of energy, there are costs associated with its recovery and use.
• Energy security: Having access to diverse energy sources and using local resources helps make energy systems more resilient.

Conclusion

With waste heat recovery, Quebec has a tremendous opportunity to produce renewable energy for buildings and industrial processes. By integrating heat capture technologies into existing infrastructure, Quebec can reduce its primary energy consumption, shrink its carbon footprint and strengthen its energy security.

ATIS Énergie has been actively promoting waste heat recovery for more than 20 years, as part of the energy management solutions we design for industrial clients. Contact us to find out what we can do for you.