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How We Did It Volume 7 — Solar Electricity


The priMED Mosaic Centre aims to be the first Net Zero energy commercial building in Alberta and is seeking certification through the Living Building Challenge. In order to be certified, the priMED Mosaic Centre must produce as much energy as it uses over one calendar year. With no natural gas line to the building, this means that all of the energy provided is electricity.

In order to achieve this lofty target the Mosaic Centre uses solar modules (photovoltaic, or PV, panels) mounted to the roof and the South West façade.  One of the key design criteria that drove the solar power system was that all of the modules and inverters needed to be mounted on the building – no PV panels located in the parking lot or offsite.  Add to that, 20% of the rooftop was to be reserved for a patio space. It should be noted here that the design team investigated other forms of renewable energy such as wind turbines but in the end, solar was the most pragmatic for the given location.

Numerous module configurations were tested – flat, angled, and a combination of the two – to determine the most economical design.  A flat-mounted design proved to be the most economical solution, even factoring in that the modules would be covered by snow in the winter months and that there would be no production between November and March.  It was more cost effective to install additional modules than to have building maintenance clear the snow off.  At Edmonton’s latitude there is very little solar potential in the winter months due to the short days and low sun angle.  So, in the summer months, the system over produces and the surplus energy is “stored” in Edmonton’s electricity grid (used by the neighborhood).  In the winter months, electricity is “withdrawn” from the grid when the system cannot produce enough to power the building.

An array of over 213 kW is flat mounted on rails (at the time this was posted it is the largest flat roof system in Alberta) and cantilevers beyond the North and South rooflines.  By doing so, the South array doubles as a sun shade for the 3rd floor of the building.  High density modules (345 Watt Sunpower X21) were required to obtain the required system size in the allotted space on the roof.  Three inverters were roof mounted – two 50 kW and one 60 kW (Solectria) – and were nested to reduce any potential shading.  Sleek and sexy black on black modules (250 Watt JA Solar) were selected to meet the architectural requirements and were coupled with micro inverters (Enphase).

Who knew that moving electrons could be so fascinating?  Explore the world of solar photovoltaics.

Meet the company that designed the priMED Mosaic Centre’s Solar Energy system.


  • Solar PV systems produce 100% clean energy – absolutely no emissions of any kind
  • Reliable, durable, and maintenance-free system
  • Utility grid acts as seasonal storage, eliminating the need for expensive and problematic battery banks
  • Alberta has the highest amount of annual sunshine in Canada, an even greater solar resource than Germany, often cited for their successful large scale deployment of solar PV
  • Long warranty – typical warranty on solar modules lasts 25 years


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