Toronto’s Yorkdale Shopping Centre has 35-acres of flat roof area that’s wide open to all-day sun. For owner and operator Oxford Properties, there was no better place to install and test a massive, 20,000-square-foot solar array. Their mission? To generate enough green energy to power the mall’s one million square feet of retail space for at least 20 years, possibly longer.
To make it work, Oxford management hired Canadian engineering company RESCo Energy Inc. in the spring of 2017 to install 600 solar panels in clusters around the mall’s roof surfaces. If calculations were correct, the panels would achieve maximum power output in midsummer, just in time to offset the peak electrical draw needed to power the mall’s air conditioning.
Malls are ideal for solar power
Driving a renewed push toward solar are the findings of the U.S. National Renewable Energy Laboratory that rooftop solar installations have the potential to meet as much as a quarter of current electricity demand for commercial properties.
According to Darryl Neate, Oxford’s director of sustainability, malls are ideal for solar installations because they have so much flat roof space. Office towers with smaller rooftops are a different proposition, because they do not offer enough space to prevent the equipment from casting shade on the solar cells.
Even so, Oxford is committed to installing a solar array on the Stack, a 36-storey office building under construction on Melville Street in Vancouver being built in accordance with the Canada Green Building Council’s new Zero Carbon Building Standard.
Oxford also installed an additional 93,000-square-feet of green roof atop the Yorkdale building concurrently with the solar arrays, providing natural insulation for the property and helping to reduce summer energy and air conditioning demands. “Our green roof helps cool in the summer as well,” Mr. Neate says.
Why solar … and why now?
In the past, the economics of solar depended on incentives, such as Ontario’s Feed-In-Tariff (FIT) Program in effect from 2009 to 2016, to promote greater use of renewable energy sources.
Even with the elimination of these incentives, rooftop solar still makes sense because of the impressive return on investment, according to Mr. Neate. The financial model for this project assumed a 20-year life expectancy for the solar cells, but with scheduled maintenance, he predicts they could easily continue to operate for 25 to 30 years.
“Obviously you don’t get much in a blizzard,” he says. “But even on cloudy days, there is energy output. And you really make hay while the sun shines. That makes a big difference for air conditioning season.”
Mr. Neate also emphasizes that the energy output each year is bell-shaped – most efficient in June through September, with less energy produced the rest of the year.
Replicate the success
As a proof of concept project, the Yorkdale test was a resounding success, with the rooftop panels providing 10 per cent more output than estimated. Over the course of the year, over 230,000 kilowatt hours (kWh) of clean electricity was generated – enough to power the mall’s interior and exterior lighting for three months. Even for one of Ontario’s largest and most sought-after retail destinations, that’s a lot of electricity.
In fact, the solar installation at Yorkdale has proven so successful that Oxford is poised to install another 1-million-square-feet of rooftop solar across their retail and industrial assets by 2022. It’s part of a commitment made by the company in 2015 to reduce the carbon emissions of their properties by 30 per cent within 10 years, says Eric Plesman, executive vice-president for Oxford North America.
When the massive sustainability project is complete, it will generate approximately 6-million kWh per year, enough to power all the homes in Collingwood for a month, Mr. Neate says. They believe that the investment in rooftop solar on Oxford’s Ontario shopping centres can reduce their clients’ electricity costs by 20 to 30 per cent, depending on utility rates and size of the installation.
Mr. Plesman is equally optimistic about the future of roof solar for malls. “We hope our work can be a model in the real estate industry by demonstrating that solar energy is both environmentally and financially smart,” he says. “By making this public commitment, we’re holding ourselves accountable to deliver industry-leading sustainability practices to our customers and communities.”