ZCB-Design v4 standard dual energy | Informa-TECH by Énergir

Why is ZCB-Design v4 a leading standard for sustainable buildings?

Against the backdrop of the energy transition and Canada’s commitment to achieving carbon neutrality by 2050, ZCB-Design v4 certification has become a leading standard for building industry stakeholders, as it “helps ensure projects are designed to optimize reductions in both operational and embodied carbon.”¹ In fact, several studies show that ultra-low-emission buildings can be more profitable over the long term than higher-emission ones, as demonstrated in particular by the report Making the Case for Zero Carbon Buildings and the action-research project Générations 1,5 °C.

Dual energy can play a key role in Quebec’s decarbonization efforts

The ZCB-Design v4 certification focuses in particular on reducing operational carbon emissions—those generated by building operations and, in turn, their heating systems. This is where dual energy comes in. Dual-energy systems use electricity to meet about 70% of heating needs and switch to natural gas when the outside temperature reaches –12 °C (or –15 °C in some regions), ensuring the right energy is used at the right time and preventing overloads on the power grid during peak demand.

A change that changes everything

Until recently, ZCB-Design v4 certification was limited to buildings that did not use combustion heating systems at temperatures above
–15 °C (even when participants used RNG²). This restriction ruled out the use of dual energy systems in much of Quebec. However, following an amendment request submitted by Énergir, the CAGBC revised its requirements to make buildings enrolled in the dual-energy program eligible for ZCB-Design v4 certification in regions where the switch from electricity to natural gas—accompanied by the purchase of RNG—occurs at –12 °C.

The CAGBC’s decision is based in particular on the fact that:

Reducing electricity consumption in buildings during peak periods improves the efficiency of power use, which in turn increases the total amount of combustion eliminated and lowers overall emissions.
The program’s subsidy and pricing structure provide a strong financial incentive for decarbonization and enable more projects to opt for dual energy.
Participants in the dual-energy program must sign a 10-year renewable natural gas (RNG) purchase agreement.
Changing the switchover point from -15 °C to -12 °C does not alter the GHG balance, provided participants use RNG.

Reducing costs, accelerating decarbonization

This amendment is excellent news for Québec’s commercial and institutional clients who are seeking ZCB-Design v4 certification and whose buildings are located in regions where the switchover occurs at −12 °C. It gives them access to Énergir grants for switching to dual energy³, of up to $250,000 per site under the streamlined track and up to $6 million per site under the customized track.⁴

In addition, customers can take advantage of Hydro-Québec’s small- and medium-power dual-energy rate to help implement their project. This change also recognizes dual energy’s contribution to the energy transition as an effective decarbonization solution.

Dual energy applied to ZCB-Design projects

Here are two real-world examples that illustrate the environmental and financial benefits of dual energy in projects seeking ZCB-Design certification.

Example 1:

Building type: Multi-tenant industrial
Area: 450,000 sq ft
Technology: Dual Fuel rooftop unit (heat pump + gas burner) providing space heating in dual-energy mode. The heat pump heats the space down to −12 °C, and the gas burner takes over below that temperature. Additional measures unrelated to dual energy are Also in place to ensure the building meets ZCB standards, including outside air heat recovery (dual core-type exchanger), an optimized building envelope, and more.

Results:

Energy savings realized with the rooftop units: 174,169 m³ (328 TCO₂)⁵
Grant awarded under the dual-energy program: $820,000 + financial assistance from Hydro-Québec ($281,000), for a total of $1,101,000, covering up to 80% of eligible additional costs.

Example 2:

Building type: Distribution centre
Area: 400,000 sq ft
Technology: Dual Fuel rooftop unit (heat pump + gas burner) providing space heating and treating outside air through heat recovery (using a dual core-type unit).

Results:

Annual GHG emissions reduction: 389.6 tons⁵
Grant awarded under the dual-energy program: $973,973 + $262,000 in financial assistance from Hydro-Québec, for a total of $1,235,973.