Solar panels in southern Alberta have been dimmed by wildfire smoke this summer

Calgarian Sean McCann installed solar panels on his home in 2018 as part of a provincial rebate program. (Photo submitted)

CALGARY — Calgarians using solar panels to help power their homes have seen big swings in the amount of energy being generated in recent weeks.

On days where there is heavy smoke in the air — wafting over from the wildfires to the west — some are finding the amount of energy produced can drop by as much as two-thirds.

Sean McCann was among those who took advantage of a provincial rebate program in 2018 and had a set of solar panels installed at his home in the northwest quadrant of the city, enough to generate just under 2000 watts of power.

"I paid really close attention to the numbers for the first year, so from June 2018 to June 2019, they accounted for just about 20 per cent of my energy usage," he said.

"When the sun is shining and I'm at home during the day, the whole house is powered by solar, my house is using the energy from solar first."

But on days when the sun has been blocked by smoke, McCann said there was a noticeable drop in power production.

On sunny summer days, McCann can see about 10 kilowatt hours of generation, which drops to between five and seven kilowatt hours on cloudy days.

On smoky days this summer, however, it dropped to about three kilowatt hours, roughly two-thirds less than when it was clear and sunny.

"From the data I have (smoke) was blocking way more energy than a typical overcast day," he said.

"It's frustrating when you try to do your part for climate change and climate change sabotages you."

B.C. is experiencing another devastating wildfire season, with hundreds of fires burning across the province, sending plumes of smoke into the air, which jet streams carry east.

The skies over southern Alberta are currently clear, with the Air Quality Health Index sitting at a three, or low risk, on Saturday but there have been days this month when it reached 10+, or high risk, due to wildfire smoke.

Looking at solar production on a larger scale, in 2020 the installed capacity in Calgary was about 7,282 kilowatt hours, according to city figures.

"In a sample of six city facilities, the July 2021 output was lower by 14 per cent compared to the four-year average," read a statement.

"Across the facilities, this ranged between eight per cent and 24 per cent lower."

Smoke isn't the only thing to blame, the statement points out, as other factors also come into play when it comes to power production.

"These could include ash or dust particles on the PV panels, lack of rain to naturally clean the panels, higher daytime temperatures (which decrease panel output efficiency), differences in cloud cover, and natural fluctuations in solar intensity," it read.

"These factors have not been evaluated in detail."

Solar panels work by way of a photovoltaic system, which converts the sun's energy into electricity. When light hits the solar cells on the panel, an electric field is created and captured.

Overall, McCann spent about $5,000 outfitting the roof of his detached garage and received about $1,400 back in rebates, which is what motivated him to make the installation.

"We just really wanted to make sure we had the infrastructure in place so when super efficient solar panels come online, we can easily swap out the old ones, put in some new ones and generate more electricity," he said.

City officials say a lack of data makes it tough to gauge how much wildfire smoke might hamper solar energy production in the future, but other jurisdictions are already noticing negative effects.

"In California, summer solar production has been observed to decrease as much as 30 per cent between non-wildfire and wildfire events. In September of 2020, the California Independent System Operator (CAISO) analyzed the impact of wildfire smoke on solar energy production," read a statement from the city.

"In a given two-week period, they found that production declined by an average of 13.4 per cent compared to the same period in the previous year. Please note, this is only a 13.4 reduction over the course of two weeks - on an annual basis this would have a smaller impact.

"The impact of forest fire smoke is an area of future research in Calgary to understand if the trends observed in California also extend to the Alberta region. This will be valuable when combined with long-term forecasts of forest fire impacts on the Calgary region."