In-Depth
2022 #CCEawards Showcase: Blatchford District Energy System – Phase 1

Photo courtesy AE.

Category: Natural Resources, Mining, Industry and Energy

Tree for Life Award and Award of Excellence Winner: Associated Engineering

With the closure of Edmonton’s city centre airport, the municipal government sought to develop an environmentally friendly community in the area. Associated Engineering (AE) collaborated with the city to design the Blatchford neighbourhood’s district energy sharing system. Powered by renewable energy for heating, cooling and hot water, it will be the largest system of its kind in Canada, with homes using heat pumps to share unused energy, thus reducing greenhouse gas (GHG) emissions.

Blatchford’s energy strategy was developed around three key pillars that increase resiliency while minimizing emissions: conservation, efficiency and renewables. Sustainable by design, the system is a model for the future.

A broad mandate

AE supported design, construction and operation planning for Blatchford’s energy system. The firm provided ownership and operations delineation, builder design guidelines, maintenance and operations guides, infrastructure and controls design, stakeholder engagement, regulatory review, end-user pricing analysis (i.e. rate setting) and GHG reductions analysis.

Review and feedback bodies included the city’s finance department, city council, public and private stakeholder committees and third-party technical reviewers. This joint approach helped ensure the city-owned and -operated community would serve a broad mandate, addressing climate change while balancing technical, financial and social needs.

Modular growth

Edmonton’s vision for Blatchford is to accommodate up to 30,000 people living, working and learning in a sustainable community that uses 100% renewable energy, is carbon-neutral, significantly reduces its ecological footprint and empowers more sustainable lifestyle choices. The city engaged AE to assess the feasibility and develop the design of this community’s renewable energy system.

As the largest application of an ambient-temperature energy distribution system in Canada, the design features: interconnected nodes of centralized heat pumps, which distribute ambient temperature water to heat pumps in each building; the integration of renewable and low-GHG energy sources, such as geoexchange (i.e. transferring heat from and to the ground), sewer heat exchange, auxiliary boilers, cooling towers and a solar photovoltaic (PV) array; and the sharing of energy between those buildings rejecting heat and those requiring it.

The system is also modular, as the neighbourhood is built out in stages over 25 years. The heat pump nodes allow flexibility for connected additional energy sources over time.

A new community is being built on the former site of Edmonton’s city-centre airport. Photo courtesy AE.

The first phase

Phase 1 involves a nearly 3-km long ambient-temperature (approximately 10 C) high-density polyethylene (HDPE) distribution pipe system (DPS), featuring supply/return fusion-welded piping up to 600 mm in diameter. The DPS is largely collocated with other major utilities.

Most of the renewable energy for heating and cooling in the first phase comes from a ground-coupled heat exchanger (GHX). Geoexchange test drilling and conductivity testing were completed to develop a site-specific 570-borehole field design. The holes were drilled 150 m beneath a naturalized stormwater retention pond.

As the neighbourhood grows, the number of boreholes will increase to 2,100. Subsequent phases will also use heat from sewer water that otherwise would be wasted.

The first phase had to be commissioned before homes could be occupied. In addition to the DPS and GHX field, it includes a 3-MW plant—dubbed Energy Centre One—with solar panels. Commissioning of the energy system was completed in 2019 and Energy Centre One, the main heating process facility, opened with an initial 1-MW capacity, using the GHX field as its renewable energy source.

High-temperature geoexchange systems, as their name suggests, require distribution at a temperature high enough to meet the most demanding load, e.g. domestic hot water. Blatchford’s system allows for more flexibility. Homeowners use water-to-air heat pumps to provide space heating and cooling and water-to-water heat pumps to provide in-floor radiant heat and domestic hot water. This arrangement helps minimize energy use and costs.

Maintaining the project’s tight schedule was critical, as subdivision development was progressing while Energy Centre One was being constructed. Quality-based selection (QBS) of a general contractor mitigated risk and Energy Centre One was successfully commissioned in advance of residential occupancy.

The main heating process facility uses a ground-coupled heat exchanger (GHX) field as its source. Photo courtesy AE.

An energy transition hub

Edmonton is home to nearly one million residents and there are plans to double the population. A changing climate, however, creates new demands for infrastructure, urban density, public transit and preparation for extreme weather events.

Blatchford showcases a possible future by using sustainable energy efficiently. Its strategy commits to higher building standards and has the potential to entirely eliminate the emissions associated with the community’s heating, cooling and domestic hot water.

This design approach will reduce GHG emissions from homes and other buildings by about 75% in comparison to a typical Edmonton neighbourhood. At its full buildout of 12,000 townhomes, the community expects to reduce emissions by about 30,000 tonnes annually.

Blatchford’s district energy sharing system began serving residential customers in September 2020. Current projections suggest the system will eventually produce more than 90% of its thermal energy output using a combination of renewable heat exchange technologies.

As a model for future developments, the Blatchford neighbourhood will showcase a carbon-neutral, cold climate, urban community in Canada, powered by shared, renewable energy.

Blatchford District Energy System – Phase 1, Edmonton

Award-winning firm (prime consultant): Associated Engineering, Edmonton. (Owen Mierke, P.Eng.; Ruben Arellano, P.Eng.; Aaron McCartie, P.Eng.; Nicole Scherer; Jermyn Wong, P.Eng.; Kevin Darrach, P.Eng.; Scott Friel, P.Eng.; Sean McInroy, P.Eng.).

Owner: City of Edmonton.

Other key players: Pinchin (mechanical engineering), ONPA Architects (architecture), Cimco Refrigeration (heat pump).