Deep Lake Water Cooling (DLWC) System

Sustainability: Cooling a City through the Power of a Lake

As we advance as a community, energy demands continue to rise, and with that there is a need to create new solutions or improve old ones. This was the case with the DLWC system. Enwave Energy Corporation (Enwave) and the City of Toronto (City) operate the DLWC system and brought RVA on board as the Lead Technical Representative to help grow the system’s capacity. RVA oversaw the environmental assessment, studies/investigations, design development, and implementation of the system’s expansion through Design-Build and Design-Bid-Build methods. The DLWC system is an award-winning sustainable deep-water source cooling project in Toronto that involves running cold water from Lake Ontario to cool buildings located in Downtown Toronto.

The system’s capacity was expanded by 251 million liters, bringing the total to 704 million liters per day. The expansion included a new 3.3 km intake to a depth of 70 m, a 93 m deep, 3 km long tunnel, new pumping and process equipment, and outfall upgrades. DLWC is a bold example of how cities can rethink infrastructure in a way that is energy-efficient, climate conscious, and built with the future in mind. This system helps shed peak electrical power and provides cooling to customers via its chilled water district energy loop. Additionally, the DLWC system has also integrated means to utilize waste heat from cooling via heat recovery electric heat pumps. This allows for efficient low-carbon heating to customers hot water district energy loop, hence, making it an environmentally friendly solution.

This initiative also aligns with Toronto’s TransformTO climate change action strategy, which is targeted to reach net-zero by 2040. The plan includes long-term goals and strategies to reduce greenhouse gas emissions, improve public health, and promote social equity. The DLWC system expansion provides 24,000 additional tons of cooling capacity that equates to 20 million ft2 of building space. As of August 2024, DLWC has saved over 130,000 tCO2e and 1.7B KWh, with future increases expected from the expansion. Refer to the latest DLWC reporting at enwave.com for updates.

Community and Future-Focused Expansion

The DLWC system has been in operation since its launch on August 17, 2004, and is the largest lake-based district energy cooling system of its kind in the world.

The expansion of the project took place in sensitive and high-traffic areas, including Downtown Toronto, a public park on Toronto Island, and active Enwave and City facilities. To avoid hinderances and inconveniences in the lives of members of the community, community engagement was a priority from the start, with public consultation beginning during the environmental assessment and continuing throughout the project. This process ensured open communication and helped address concerns from residents, facility staff, agencies, and First Nations communities.

To protect public health and safety, minimize disruptions, and maintain operations, the team implemented measures such as continuous facility operation, regular public updates, environmental and cultural accommodations, and the maintenance of roads, public spaces, and safe access points.

As cooling demand in Toronto is projected to increase by 35% in the coming years, there is a growing need to shift away from non-renewable sources toward more sustainable options. To meet this demand, the DLWC system needed to expand its capacity within a limited timeframe, increasing its ability to deliver renewable, lake-based cooling to the City’s District Energy System. To meet the project’s objectives, a new deep lake water intake and conveyance system was developed to serve both the City and Enwave. This included extensive studies, environmental assessments, stakeholder consultations, and infrastructure upgrades at both City and Enwave facilities. Existing and inactive infrastructure was repurposed, and alternative project delivery and procurement methods were used to maximize efficiency.

When it came to managing the DLWC system project, strategic design advancement was carried out in parallel with traditional linear design to accelerate the schedule, while critical path tasks were subdivided for faster completion. While the COVID-19 pandemic occurred during the midst of the project, the project setup, schedule, and necessary requirements were met in time for launch. Experts were engaged in various engineering disciplines including environmental, planning, water treatment, structural, tunneling, mechanical, electrical, I&C, hydraulics, marine, and yoast services.

Essentially, the DLWC system ensures the continued and uninterrupted operation of critical infrastructures. This reliability is vital for the community, providing consistent and efficient cooling services as well as providing additional capacity for future growth. This project is one of many that showcases the essential role of engineers in society, from planning and implementing infrastructure projects to ensuring we meet environmental and community needs.